*****AMERICAN HEART JOURNAL*****
(REFERENCE 1 OF 63) 96428262
Miga DE Case CL Gillette PC Interatrial septal aneurysms and atrial arrhythmias in infants.
In: Am Heart J (1996 Oct) 132(4):776-8
ISSN: 0002-8703
Studies have suggested that interatrial septal aneurysms (IASAs) may be the initiating mechanism of supraventricular tachycardia (SVT) in newborns and infants. A retrospective study was performed to determine the incidence of IASAs in 30 infants with atrial arrhythmias (SVT, atrial flutter, or frequent premature atrial contractions) and their possible relation to the mechanism of atrial arrhythmias. An IASA was defined as dilation of the septum > 5 mm beyond the plane of the atrial septum and associated with redundant tissue and abnormal mobility. The study patients were compared with age and sex-matched control subjects. Four (13%) of the 30 study patients and 2 (7%) of 30 control subjects had an IASA (difference not significant). In contrast to previous reports, this study demonstrates that there is not a significant relation between the presence of IASAs and the onset and recurrence of atrial arrhythmias.
Institutional address: South Carolina Children's Heart Center Medical University of South Carolina Charleston 29425 USA.
(REFERENCE 2 OF 63) 95028940
Stein KM Engelstein ED Lippman N Lerman BB Physiologic role of atrio-Hisian and nodo-Hisian bypass tracts in supraventricular tachycardia.
In: Am Heart J (1994 Oct) 128(4):759-68
ISSN: 0002-8703
Atrio-Hisian bypass tracts are considered to be rare electrophysiologic curiosities. The prevalence and functional significance of these tracts are unknown. We examined the incidence of atrio-Hisian and nodo-Hisian bypass tracts, their electrophysiologic manifestations, and their physiologic role in supraventricular tachycardia in 200 consecutive patients referred for evaluation of supraventricular tachycardia. In one patient it was demonstrated for the first time that a concealed (retrograde only) nodo-Hisian bypass tract functioned as the retrograde limb of orthodromic reciprocating tachycardia. The VA interval was negative during tachycardia, similar to that sometimes observed in atrioventricular nodal reentry. In a second patient an anterograde and retrograde conducting pathway resulted in a pseudo Wolff- Parkinson-White electrocardiographic pattern and served as an "innocent bystander," permitting a rapid ventricular response during atrial flutter. In conclusion, although atrio-Hisian and nodo-Hisian bypass tracts are rare, they are sufficiently prevalent to make them observable in a larger referral series. Most importantly, they may participate as bystanders during supraventricular tachycardia or as either the anterograde or retrograde limbs of reciprocating tachycardia. They may possess features that mimic Wolff-Parkinson- White syndrome and/or AV nodal reentry.
Institutional address: Department of Medicine New York Hospital-Cornell Medical Center NY 10021.
(REFERENCE 3 OF 63) 94354086
Grossman DS Cohen TJ Goldner B Jadonath R Pseudorecurrence of paroxysmal supraventricular tachycardia after radiofrequency catheter ablation.
In: Am Heart J (1994 Sep) 128(3):516-9
ISSN: 0002-8703
Over an 11-month period (November 1992 to October 1993), 32 radiofrequency catheter ablations were performed for recurrent symptomatic supraventricular tachycardia in 17 patients with atrioventricular (AV) nodal reentry, 13 with AV reentry with an accessory pathway), and 2 with both AV and AV nodal reentry. Each patient underwent both diagnostic and therapeutic electrophysiologic study with radiofrequency catheter ablation in a single session. Twelve of the 32 patients had recurrent symptoms after catheter ablation. A repeat study was performed in 9 of the 12 patients. At 7.7 +/- 0.8 months (range 4 to 11) of follow-up only one patient had had a true symptomatic recurrence. Additional sessions of ablation cured this patient. We conclude that pseudorecurrence of paroxysmal supraventricular tachycardia is a common phenomenon in patients after radiofrequency catheter ablation. Follow-up electrophysiologic study demonstrates and helps differentiate pseudo from true paroxysmal supraventricular tachycardia recurrence.
Institutional address: Department of Medicine North Shore University Hospital-Cornell University Medical College Manhasset NY 11030.
(REFERENCE 4 OF 63) 98247817
Brembilla-Perrot B Jacquemin L Houplon P Houriez P Beurrier D Berder V Terrier de la Chaise A Louis P Increased atrial vulnerability in arrhythmogenic right ventricular disease.
In: Am Heart J (1998 May) 135(5 Pt 1):748-54
ISSN: 0002-8703
Supraventricular tachyarrhythmias (SVTA) may occur in patients with the arrhythmogenic right ventricular dysplasia (ARVD). The purpose of the study was to evaluate the incidence of SVTA in 47 patients with ARVD proved by right ventricular angiography. Thirty-three men and 14 women, aged 21 to 72 years (mean 44 +/- 18) were admitted for nonsustained or sustained ventricular tachycardia. Eight patients had a history of spontaneous SVTA several years before ventricular tachycardia occurrence. Protocol of the study consisted of programmed atrial stimulation with one and two extrastimuli delivered during sinus rhythm and two driven rhythms (600 and 400 msec), programmed ventricular stimulation with up to three extrastimuli and was performed in the control state and after infusion of isoproterenol. The results of programmed atrial stimulation were compared with those obtained in 36 asymptomatic subjects without heart disease and with a mean age of 50 +/- 18 years (control group). Sustained SVTA (> 1 minute) was induced in seven of eight patients with spontaneous SVTA, in 27 (69%) of those with ARVD, who did not have spontaneous SVTA, and in two control subjects (5.5%) (p < 0.001). SVTA was inducible in the control state, but ventricular tachycardia induction required isoproterenol in 11 of 27 patients. Two patients without SVTA history but with inducible SVTA developed later spontaneous SVTA. ARVD was associated with a significantly higher incidence of inducible SVTA than in a control population. Supraventricular tachycardias may precede ventricular tachycardias. This association argues for a diffuse myocardial disorder in ARVD.
Registry Numbers: 7683-59-2 (Isoproterenol)
Institutional address: Cardiology A CHU of Brabois Vandoeuvre les Nancy France.
(REFERENCE 5 OF 63) 96315911
Drago F Turchetta A Calzolari A Giordano U Di Ciommo V Santilli A Pompei E Ragonese P Reciprocating supraventricular tachycardia in children: low rate at rest as a major factor related to propensity to syncope during exercise.
In: Am Heart J (1996 Aug) 132(2 Pt 1):280-5
ISSN: 0002-8703
Reciprocating supraventricular tachycardia may have several clinical presentations, with symptoms often more severe during exercise or emotional stress. This study shows by using transesophageal atrial pacing, the factors related to syncope during exercise. Between May 1989 and June 1994, transesophageal atrial pacing was performed at rest and during exercise in 75 children aged > 6 years with suspected or documented episodes of paroxysmal supraventricular tachycardia. Reciprocating supraventricular tachycardia could be induced both at rest and during exercise in 22 patients (8 girls, 14 boys; mean age 10.6 +/- 2.7 years, range 7 to 15 years) with ventriculoatrial interval < 70 msec in 11 patients and > 70 msec in 11. At rest, all patients had palpitations caused by the induction of tachycardia. After conversion to sinus rhythm, when tachycardia was induced during exercise, symptoms did not change in 14 patients (group A), whereas symptoms worsened (presyncope) in eight (group B). The statistical analysis showed a significant difference of mean reciprocating supraventricular tachycardia rate at rest between the two groups (group A, 211 +/- 23 beats/min; group B, 173 +/- 33 beats/min; p = 0.0057) and reciprocating supraventricular tachycardia rate variation from rest to exercise (group A, 62 +/- 18 beats/min; group B, 105 +/- 24 beats/min; p = 0.0001). These data suggest that children with low tachycardia rate during normal activities may have syncope more frequently, independently of the tachycardia rate during exercise or emotional stress.
Institutional address: Department of Pediatric Cardiology Bambino Gesu Children's Hospital Scientific Institute of Research Rome Italy.
(REFERENCE 6 OF 63) 96312427
Johnson TB Varney FL Jr Gillette PC McKay CA Case CL Whitsett JH Knick BJ Lack of proarrhythmia as assessed by Holter monitor after atrial radiofrequency ablation of supraventricular tachycardia in children.
In: Am Heart J (1996 Jul) 132(1 Pt 1):120-4
ISSN: 0002-8703
The purpose of this study was to assess the short-term arrhythmogenicity of atrial radiofrequency (RF) ablation lesions in children. Patients with the greatest exposure to RF energy comprised the study group. Holter data on 35 RF ablation procedures in 31 patients with a median age of 13.2 years (range 3 months to 20 years) was retrospectively analyzed. Patients received an average of 19.9 (SD = 13.6) RF lesions, all delivered by an atrial approach. Supraventricular ectopy and ventricular ectopy were compared immediately before and after and 4 to 9 weeks after RF ablation by serial Holter monitoring. Factors thought to possibly predispose patients to a proarrhythmic effect were used to define subgroups for separate analysis. No increase in ambient supraventricular ectopy or ventricular ectopy was observed either immediately after or 4 to 9 weeks after RF ablation compared with the baseline Holter recordings. Children exposed to relatively large doses of RF energy may demonstrate transient and asymptomatic nonsustained tachycardias in the short term. However, no new sustained tachycardias and no increase in supraventricular or ventricular ambient ectopy are detected by short-term Holter monitoring.
Institutional address: South Carolina Children's Heart Center Medical University of South Carolina Charleston SC 29425 USA.
(REFERENCE 7 OF 63) 96205245
Sarter BH Hook BG Callans DJ Marchlinski FE Effect of bundle branch block on local electrogram morphologic features: implications for arrhythmia diagnosis by stored electrogram analysis.
In: Am Heart J (1996 May) 131(5):947-52
ISSN: 0002-8703
Analysis of stored local ventricular electrogram recordings is a useful diagnostic tool in the evaluation of patients with implantable cardioverter defibrillators. Visual analysis of local electrogram morphologic features has been demonstrated to be useful in distinguishing ventricular tachycardia from supraventricular rhythm. The effect of bundle branch block (BBB) aberration during supraventricular tachycardia on local electrogram morphologic features is not entirely clear. Erroneous diagnoses resulting from a change in electrogram morphologic features with BBB may occur. To determine whether the development of BBB can produce a change in local electrogram morphologic features and whether this change is dependent on the site of recording, we retrospectively reviewed local electrogram recordings from 23 patients who had intermittent BBB during electrophysiologic evaluation of documented or suspected supraventricular tachycardia. Local electrogram recordings from catheters placed in the right ventricular apex and coronary sinus during supraventricular tachycardia with BBB aberrancy were compared with recordings during narrow complex supraventricular tachycardia or normal sinus rhythm. Bipolar recordings were made with a 5 mm interelectrode distance with filter settings at 40 to 400 Hz. Three independent blinded observers defined the paired electrograms as the same or distinctly different. During right BBB a change in electrogram morphologic features was demonstrated in 11 (85%) of 13 recordings from the right ventricular apex and in only 1 (8%) of 12 recordings from the coronary sinus. In contrast, during left BBB a change in electrogram morphologic features was seen in 6 (100%) of 6 recordings from the coronary sinus and in only 1 (8%) of 13 recordings from the right ventricular apex. These results demonstrate that when the described recording techniques are used, a change in local ventricular electrogram morphologic features BBB is predominantly manifest in recording sites ipsilateral to the BBB, whereas recording sites contralateral to the BBB are relatively unaffected. This information may have implications regarding interpretation of stored electrograms when an attempt is made to establish a rhythm diagnosis leading to implantable cardioverter defibrillator therapy.
Institutional address: Clinical Electrophysiology Laboratory Philadelphia Heart Institute PA 19104 USA.
(REFERENCE 8 OF 63) 96133149
Weindling SN Saul JP Walsh EP Efficacy and risks of medical therapy for supraventricular tachycardia in neonates and infants.
In: Am Heart J (1996 Jan) 131(1):66-72
ISSN: 0002-8703
To assess the efficacy and safety of current pharmacologic therapy for supraventricular tachycardia (SVT) in infants, we reviewed 112 infants treated between July 1985 and March 1993. The SVT mechanism was determined by esophageal electrophysiologic study and involved an accessory pathway in 86, atrioventricular (AV) node reentry in 10, atrial muscle reentry in 11, and an ectopic atrial tachycardia in 5 patients. Of six infants not treated, none had clinical recurrences of SVT. Of the 106 patients treated, 70% remained free of tachycardia while receiving digoxin, propranolol, or both. Class I antiarrhythmic agents were necessary for 13 patients, and class III agents were required for another 13 infants. Verapamil was used in one infant with AV node reentry tachycardia. Nine infants with complex clinical presentations were believed to have failed medical management and underwent radiofrequency ablation. Five patients died, four of complications related to structural heart disease and one shortly after radiofrequency ablation was performed. No deaths appeared to be related to antiarrhythmic medications. No drug-related side effects requiring medication change occurred, and no proarrhythmia was observed. Thus medical therapy appears to be effective and safe in infants with SVT. Radiofrequency ablation should be reserved for rare infants who fail aggressive medical regimens or when the situation is complicated by ventricular dysfunction, severe symptoms, or complex congenital heart disease.
Registry Numbers: 20830-75-5 (Digoxin) 52-53-9 (Verapamil) 525-66-6 (Propranolol)
Institutional address: Department of Cardiology Children's Hospital Boston Mass. USA.
(REFERENCE 9 OF 63) 96021216
Tanel RE Walsh EP Lulu JA Saul JP Sotalol for refractory arrhythmias in pediatric and young adult patients: initial efficacy and long-term outcome.
In: Am Heart J (1995 Oct) 130(4):791-7
ISSN: 0002-8703
Sotalol is an antiarrhythmic medication that has properties of both a beta-blocker and a class III agent and has been used safely and effectively to treat arrhythmias of multiple mechanisms in pediatric patients. The purpose of this study was to review our institutional experience with sotalol in 45 patients with refractory arrhythmias and determine their long-term outcome. Patients responded to sotalol with 80% efficacy and a 22% incidence of adverse side effects. The mean sotalol dose was 116 mg/m2/day, and the average duration of therapy was 15.2 months. In spite of 80% efficacy, only 22% of patients remained on sotalol long-term. Sotalol was discontinued most commonly for either spontaneous resolution of disease or definitive cure by radiofrequency ablation. Other reasons for discontinuation of effective therapy included adverse side effects and arrhythmia control with either an antitachycardia pacemaker or another medication. One patient died while taking sotalol, but this case was considered a failure of treatment rather than an adverse side effect. Of the patients who still receive therapy, several have complex structural heart disease and require a combination of therapies, including sotalol, for adequate rhythm control.
Registry Numbers: 3930-20-9 (Sotalol)
Institutional address: Department of Cardiology Children's Hospital Boston MA 02115 USA.
(REFERENCE 10 OF 63) 94226017
Chiang CE Chen SA Yang CR Cheng CC Wu TR Tsai DS Chiou CW Chen CY Wang SP Chiang BN et al Major coronary sinus abnormalities: identification of occurrence and significance in radiofrequency ablation of supraventricular tachycardia.
In: Am Heart J (1994 May) 127(5):1279-89
ISSN: 0002-8703
Coronary sinus catheterization is important in electrophysiologic study of patients with supraventricular tachycardia. It can provide an anatomic guide for localization of slow atrioventricular nodal pathway and accessory pathways in the posteroseptal area and left- sided atrioventricular ring. However, the morphologic features of the coronary sinus and its significance in patients with supraventricular tachycardia have not been determined. Four hundred eight patients with accessory pathway-mediated tachyarrhythmia and atrioventricular nodal reentrant tachycardia underwent coronary arteriography for a coronary sinus venogram before electrophysiologic study and radiofrequency ablation. The venous phase of left coronary arteriography that delineated the morphologic features of the coronary sinus was carefully evaluated and recorded in multiple projections. Major coronary sinus abnormalities were defined, and they were found in 12 patients (2.9%). Six patients had angulation of the coronary sinus, 4 patients had hypoplasia of the coronary sinus, 1 patient had narrowing of the proximal coronary sinus, and 1 patient had a fistula from persistent left superior vena cava to the coronary sinus. Of 175 patients with atrioventricular nodal reentrant tachycardia, only 1 patient had major coronary sinus abnormalities (proximal angulation), whereas of 233 patients with accessory pathway- mediated tachycardia, 11 patients had major coronary sinus abnormalities (0.6% vs 4.7%, p < 0.05). The accessory pathways in patients with major coronary sinus abnormalities were located exclusively in the left free wall and posteroseptal area. Proper coronary sinus catheterization could be accomplished in 396 patients with a normal coronary sinus, whereas it could be accomplished in only 1 of the 12 patients with major coronary sinus abnormalities (396/396 vs 1/12, p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
Institutional address: Department of Medicine Veterans General Hospital--Taipei Taiwan Republic of China.
(REFERENCE 11 OF 63) 93151113
Chiang CE Chen SA Wang DC Tsang WP Hsia CP Ting CT Chiang CW Wang SP Chiang BN Chang MS Arrhythmogenicity of catheter ablation in supraventricular tachycardia.
In: Am Heart J (1993 Feb) 125(2 Pt 1):388-95
ISSN: 0002-8703
To evaluate arrhythmogenicity in patients who receive a modified direct-current (DC) shock ablation (distal pair of electrodes connected in common as the cathode) or radiofrequency (RF) ablation of supraventricular tachycardia, a prospective study was performed with signal-averaged ECG, 24-hour Holter monitoring, electrophysiologic study (EPS) for ventricular tachycardia (VT), and treadmill exercise test. Sixty-nine consecutive patients with documented paroxysmal supraventricular tachycardia were included. Twenty-eight patients proved to have atrioventricular nodal reentrant tachycardia, and 41 patients had atrioventricular reciprocating tachycardia that involved accessory atrioventricular pathways. The first 34 patients received DC shock ablation and the other 35 patients received RF ablation. Signal-averaged ECG, Holter monitoring, and EPS for VT were performed before ablation, immediately after ablation, then 1 week, 2 weeks (Holter monitoring), 1 month (except EPS), and 3 months after ablation. Treadmill exercise testing was performed before ablation, and at 1 week and 3 months after ablation. The root mean square, low-amplitude signal and QRS duration of signal-averaged ECG disclosed no significant change after either DC or RF ablation up to 3 months. Late potential developed in only one patient in the DC shock group and it was considered to be innocuous because neither VT nor ventricular fibrillation was noted or induced. Increases in the number of ventricular premature contractions and in short-run VT were detected by Holter monitoring in the first week after either mode of ablation (p < 0.001 for the DC shock group; p < 0.05 for the RF group), which were greater (p < 0.05) and lasted longer in the DC shock group than in the RF group.(ABSTRACT TRUNCATED AT 250 WORDS)
Institutional address: Department of Medicine National Yang-Ming Medical College Taipei Taiwan Republic of China.
*****AMERICAN JOURNAL OF CARDIOLOGY*****
(REFERENCE 12 OF 63) 97073941
Fish FA Mehta AV Johns JA Characteristics and management of chaotic atrial tachycardia of infancy [see comments]
In: Am J Cardiol (1996 Nov 1) 78(9):1052-5
ISSN: 0002-9149
Chaotic atrial tachycardia was observed in 7 infants without underlying structural heart disease. Clinical presentation and approach to management are discussed, with particular attention to the use of propafenone for this uncommon pediatric arrhythmia.
Comment in: Am J Cardiol 1997 Aug 1;80(3):395-6
Registry Numbers: 54063-53-5 (Propafenone)
Institutional address: Department of Pediatrics Vanderbilt University Medical Center Nashville Tennessee 37232-2572 USA.
(REFERENCE 13 OF 63) 95366384
Giorgberidze I Saksena S Krol RB Mathew P Efficacy and safety of radiofrequency catheter ablation of left-sided accessory pathways through the coronary sinus.
In: Am J Cardiol (1995 Aug 15) 76(5):359-65
ISSN: 0002-9149
Radiofrequency catheter ablation of left-sided accessory pathways (APs) with the use of an endocardial technique carries all potential risks of left heart catheterization. We analyzed the determinants of success, efficacy, and safety of radiofrequency catheter ablation from the coronary sinus (CS), as a potential alternative to the endocardial technique in these patients. Thirteen patients (mean age 40 +/- 20 years) with 15 left-sided APs and a history of symptomatic supraventricular tachycardia were included in the study. Nine APs were localized in the left posteroseptal region, and the remaining 6 in the left free wall. Ablation from CS was attempted in 12 patients with 14 APs. In 1 patient ablation within the CS was not deemed safe because of a small venous lumen. All 14 APs were successfully ablated using either CS ablation alone or combined with the endocardial technique. Efficacy of the CS ablation as a primary technique was 56% (5 of 9 APs). In 5 additional APs, ablation in the CS eliminated pathway conduction after failed endocardial attempts. CS ablation either as a primary or a secondary technique eliminated conduction in 10 of 14 APs (71.4%) (group 1). In the remaining 4 APs (group 2), the primary CS attempt was unsuccessful and APs were ablated with a subsequent endocardial approach. Determinants of success for the CS method were local AP to atrial and/or ventricular electrogram amplitude ratios > or = 1 (p < 0.05). The success rate of CS ablation was 83% in the left posteroseptal APs adjoining the branching point of the middle cardiac vein or a CS anomaly.(ABSTRACT TRUNCATED AT 250 WORDS)
Institutional address: Arrhythmia & Pacemaker Service Eastern Heart Institute Passaic New Jersey USA.
(REFERENCE 14 OF 63) 95100110
Wagshal AB Pires LA Yong PG Moser SA Mazzola F Mittleman RS Huang SK Usefulness of follow-up electrophysiologic study and event monitoring after successful radiofrequency catheter ablation of supraventricular tachycardia. Atakr Multicenter Investigators Group.
In: Am J Cardiol (1995 Jan 1) 75(1):50-2
ISSN: 0002-9149
We assessed the usefulness of routine follow-up electrophysiologic studies after successful catheter ablation for supraventricular tachycardia and the role of event monitoring as an alternative modality in 310 patients at 11 centers using an investigational catheter ablation system with closed-loop temperature control. A routine follow-up electrophysiologic study between 1 and 3 months after ablation was required as part of the study protocol, and patients developing palpitations after ablation were encouraged to use event monitors. Recurrence of the initially targeted arrhythmia developed in 23 patients (7.4%) at a mean of 1.5 +/- 1.5 months after ablation. However, only 2 of these 23 recurrences were discovered by routine follow-up electrophysiologic study in asymptomatic patients (both with concealed accessory pathways); in the remaining 21 patients a positive follow-up electrophysiologic study was heralded by either recurrent symptoms, documented recurrent supraventricular tachycardia, and/or preexcitation on the electrocardiogram. Eighteen patients complained of palpitations after ablation and received an event monitor, which correctly diagnosed another cause of palpitations and ruled out recurrence of the ablated arrhythmia in 8 patients. Thus, the combination of clinical follow-up and event monitoring appears to be an effective alternative to routine follow- up electrophysiologic studies after catheter ablation of supraventricular tachycardia.
Institutional address: Department of Medicine University of Massachusetts Medical Center Worcester 01655.
(REFERENCE 15 OF 63) 95029046
Park JK Halperin BD McAnulty JH Kron J Silka MJ Comparison of radiofrequency catheter ablation procedures in children, adolescents, and adults and the impact of accessory pathway location.
In: Am J Cardiol (1994 Oct 15) 74(8):786-9
ISSN: 0002-9149
Radiofrequency (RF) catheter ablation is an accepted treatment for supraventricular tachycardia. However, the determinants of success, difficulty, or risk of complication associated with ablation have not been defined. This study evaluated patient age and location of the accessory or extranodal pathway as determinants of these procedural variables. Patients were stratified by age, with those aged 2 to 12 years classified as children, those aged 13 to 19 years as adolescents, and those > or = 20 years as adults. Locations were defined as right, septal, or left free wall accessory pathways, or extranodal slow pathways associated with atrioventricular node reentrant tachycardia. A total of 443 RF ablation procedures performed in 413 patients were evaluated. All procedures were performed in the same laboratory by the same group of physicians. Success rates for ablation of supraventricular tachycardia did not differ among the 3 age groups, ranging from 93% to 95%. Procedural aspects, including total procedure time, fluoroscopy time, and number of applications of RF energy also did not differ by age group. However, analysis of outcome and procedural complexity with respect to pathway location demonstrated that ablation of right free wall and septal accessory pathways was significantly more difficult than left free wall or slow pathway (success rates of 85% and 88% vs 97% and 98%, respectively, p = 0.01 and 0.02), irrespective of age. Additionally, right free wall pathways required significantly greater procedure time (mean = 5.1 hours), fluoroscopy time (mean = 78 minutes), and RF applications (median = 16) than ablations performed at other sites.(ABSTRACT TRUNCATED AT 250 WORDS)
Institutional address: University Arrhythmia Service Oregon Health Sciences University Portland.
(REFERENCE 16 OF 63) 94354113
Figa FH Gow RM Hamilton RM Freedom RM Clinical efficacy and safety of intravenous Amiodarone in infants and children.
In: Am J Cardiol (1994 Sep 15) 74(6):573-7
ISSN: 0002-9149
The effectiveness and safety of intravenous amiodarone in children are not well established. This study reviewed its use in 30 infants and children for life-threatening tachyarrhythmias: 18 patients (19 episodes) with supraventricular tachycardia, and 12 with ventricular tachycardia. Eighteen patients had structural heart defects with arrhythmias that occurred after surgery. The mean loading dose was 5 mg/kg infused over 1 hour, with a starting maintenance dose of 5 micrograms/kg/min. In 18 treatment episodes, amiodarone was used alone or in combination with digoxin. Thirteen patients received amiodarone combined with other antiarrhythmic agents. Intravenous amiodarone was effective or partially effective in 94% of patients, achieving a therapeutic effect in a median time of 1 day (range 1 hour to 5 days). The mean effective maintenance dose was 9.5 micrograms/kg/min (13.7 mg/kg/day), and median treatment duration was 5 days (range 1 to 30). Adverse effects occurred in 18 patients (58%), however none necessitated termination of amiodarone therapy. Potentially significant electrocardiographic abnormalities occurred in 5 patients during combination antiarrhythmic therapy with propafenone. Sinus bradycardia requiring temporary postoperative pacing occurred in 3 patients treated with amiodarone alone. Intravenous amiodarone used alone or in combination therapy is an effective treatment for resistant, life-threatening arrhythmias in infants and children. Combination drug therapy with propafenone must be used cautiously. Potential bradycardia pacing may be necessary during administration of amiodarone after surgery.
Registry Numbers: 1951-25-3 (Amiodarone)
Institutional address: Department of Paediatrics Hospital for Sick Children Toronto Ontario Canada.
(REFERENCE 17 OF 63) 94337694
Rhodes LA Walsh EP Saul JP Programmed atrial stimulation via the esophagus for management of supraventricular arrhythmias in infants and children.
In: Am J Cardiol (1994 Aug 15) 74(4):353-6
ISSN: 0002-9149
This report describes the use of programmed atrial stimulation via the esophagus to predict the clinical efficacy of various management strategies for supraventricular arrhythmias in infants and children. A total of 203 transesophageal electrophysiologic studies were performed in 132 patients. Therapies evaluated included medications from each antiarrhythmic class, the Valsalva maneuver, follow-up of radiofrequency ablation, and no therapy. The transesophageal technique appeared to be adequate for inducing tachycardia, yielding a low false-negative rate. Overall, the predictive value of a negative study was high (89%), and increased to 96% when stimulation was performed in the presence of isoproterenol. However, the positive predictive value was significantly lower both with (72%, p < 0.00001) and without (60%, p < 0.0001) isoproterenol. These results were due in part to a very low positive predictive value when evaluating either digoxin and/or beta-blocker therapy, 62% vs 82% for the remaining studies. When clinical tachycardia cannot be induced with therapy, transesophageal techniques can be used to predict freedom from many supraventricular tachycardias for most therapies in children. However, induction of tachycardia may not predict treatment failure. Transesophageal pacing to evaluate arrhythmia therapy may be most useful when managing either severe symptoms, multiple recurrences, or the results of radiofrequency ablation.
Institutional address: Department of Cardiology Children's Hospital Harvard Medical School Boston Massachusetts 02115.
(REFERENCE 18 OF 63) 98060639
Kugler JD Danford DA Houston K Felix G Radiofrequency catheter ablation for paroxysmal supraventricular tachycardia in children and adolescents without structural heart disease. Pediatric EP Society, Radiofrequency Catheter Ablation Registry.
In: Am J Cardiol (1997 Dec 1) 80(11):1438-43
ISSN: 0002-9149
Since 1990, management options available for children with paroxysmal supraventricular tachycardia (PSVT) have included radiofrequency catheter ablation (RCA). To determine the efficacy and safety of the procedure and to maintain a database for long-term follow-up, the Pediatric Electrophysiology Society began a Pediatric RCA Registry on January 1, 1991, to which 46 centers have submitted data from 4,135 total children and adolescents (patient age 0.1 to 20.9 years) who underwent 4,651 RCAs (through September 15, 1996). Of the 88% with a structurally normal heart, PSVT mechanisms (n = 4,030) included 3,110 accessory pathways and 920 atrioventricular node reentry tachycardia (AVNRT) during 3,653 procedures for 3,277 patients. During the 7 years of the Registry, analysis of indications for the procedure has shown a gradual shift. During the first year of the Registry for this PSVT group, "medically refractory tachycardia" was listed as the indication for 44% and "patient choice" was listed as 33%, compared with 29% and 58%, respectively, for the years 1995 to 1996 (p <0.005). Registry results were: 90% immediate success for accessory pathways (95% for left lateral; 87% for septal; 86% for right free wall) and 96% for AVNRT; mean fluoroscopy time 47.6 +/- 40 SD minutes; procedure time 257 +/- 157 SD minutes; major complication rate at the time of the procedure 3.2%. Procedure-related deaths included 1 immediate and 3 at 2, 12 and 68 weeks after the procedure (2 were infants). Follow-up revealed 77% and 71% freedom from recurrence at 3 years for accessory pathways AVNRT, respectively, and rare (<1%) detection of additional complications. RCA has evolved into a standard management option for PSVT in children with a structurally normal heart. RCA for children and adolescents should be recommended after consideration of the procedural risk/benefit compared with that of other management options, the natural history, and individual tolerance/symptoms related to PSVT.
Institutional address: Joint Division of Pediatric Cardiology UN Medical Center/Creighton University Omaha Nebraska 68114 USA.
(REFERENCE 19 OF 63) 96216694
Van Hare GF Lesh MD Ross BA Perry JC Dorostkar PC Mapping and radiofrequency ablation of intraatrial reentrant tachycardia after the Senning or Mustard procedure for transposition ofthe great arteries.
In: Am J Cardiol (1996 May 1) 77(11):985-91
ISSN: 0002-9149
The Senning and Mustard procedures are often associated with the development of atrial tachyarrhythmias, which may be a cause of sudden death. We hypothesized that atrial surgery creates barriers to impulse propagation, establishing potential routes for atrial reentry, and that mapping combined with knowledge of the surgical anatomy could identify zones that are critical to the tachycardia to be targeted for radiofrequency catheter ablation. Patients underwent mapping to identify early sites of atrial activation that were related to anatomic or surgically created obstacles, with confirmation by pacing to demonstrate concealed entrainment. Radiofrequency lesions were placed to connect these obstacles, while observing for tachycardia termination. Thirteen tachycardias were attempted in 10 patients, 10 successfully. Three patients had 2 distinct tachycardias. Successful sites were in right atrial tissue, although in many, a retrograde approach to the pulmonary venous atrium was necessary. Ablation of the clinically documented tachycardia was successful in 9 of 10 patients. The most common successful site was the region of the coronary sinus mouth, approached antegrade or retrograde. Ablation of intraatrial reentrant tachycardias after the Senning or Mustard procedure is feasible using concealed entrainment mapping techniques, but requires a detailed knowledge of the individual surgical anatomy and the ability to approach the pulmonary venous atrium. Radiofrequency ablation offers significant advantages over other management modalities in this patient group.
Institutional address: Department of Pediatrics Rainbow Babies and Children's Hospital Case Western Reserve School of Medicine Cleveland Ohio 44106 USA.
(REFERENCE 20 OF 63) 96190305
Hopson JR Buxton AE Rinkenberger RL Nademanee K Heilman JM Kienzle MG Safety and utility of flecainide acetate in the routine care of patients with supraventricular tachyarrhythmias: results of a multicenter trial. The Flecainide Supraventricular Tachycardia Study Group.
In: Am J Cardiol (1996 Jan 25) 77(3):72A-82A
ISSN: 0002-9149
Patients with supraventricular arrhythmias have been safely and effectively treated with flecainide. We conducted an open-label, 20- center trial to define further the safety and efficacy profile of oral flecainide in patients with supraventricular arrhythmias, including atrial tachycardias (ectopic or multifocal), atrial- ventricular tachycardias (reentrant), paroxysmal atrial fibrillation/flutter (PAF), and chronic atrial fibrillation (CAF). Our study population of 151 patients with documented supraventricular arrhythmias requiring treatment included 67 with paroxysmal supraventricular tachycardia (PSVT), 67 with PAF (symptoms < 15 days), and 17 with CAF (symptoms > of = 15 days)> The initial flecainide dose of 100 mg twice daily could be increased by 50 mg bid every 4 days to a maximum of 200 mg twice daily. Patients who were effectively treated could receive flecainide for 1 year. The study was terminated April 26, 1989, in response to interim results reported by the Cardiac Arrhythmia Suppression Trial (CAST). All patients were removed from the study by August 1989. At study termination 87% of PSVT, 73% of PAF, and 56% of CAF patients had improved symptomatically while on flecainide therapy. Eleven patients experienced cardiac adverse experiences: proarrhythmic events (3 patients), new or worsened congestive heart failure (7 patients), sinus pauses (1 patient). Cardiac side effects appeared to be more frequent in patients in the CAF group (5/17 patients), all of whom had structural heart disease. Overall, 45 (67%) PSVT, 43 (64%) PAF, and 9 (56%) CAF patients reported at least 1 noncardiac adverse experience; the most common were abnormal vision, dizziness, and headaches. One patient from the CAF group died; the death was considered to be unrelated to flecainide. Flecainide appears to be safe and effective treatment for patients with supraventricular arrhythmias of a variety of mechanisms and appears particularly effective for patients with PSVT. The efficacy is lowest and side effects most frequent in patients with CAF, as seen with other trials of antiarrhythmic medication in these patients. In the context of the CAST experience and other trials of antiarrhythmic drugs in patients with CAF, the balance of risk and benefit of therapy should be considered carefully before initiating treatment.
Registry Numbers: 54143-55-4 (Flecainide)
Institutional address: Department of Internal Medicine University of Iowa Hospitals and Clinics Iowa City 52242 USA.
(REFERENCE 21 OF 63) 96016328
Lee SH Chen SA Wu TJ Chiang CE Cheng CC Tai CT Chiou CW Ueng KC Chang MS Effects of pregnancy on first onset and symptoms of paroxysmal supraventricular tachycardia.
In: Am J Cardiol (1995 Oct 1) 76(10):675-8
ISSN: 0002-9149
It is important for women to understand the risk of first onset and symptomatic exacerbation of paroxysmal supraventricular tachycardia (SVT) during pregnancy. Reports regarding the effects of pregnancy on first onset and symptomatic exacerbation of paroxysmal SVT have been controversial, and have not been conducted in a systematic fashion. Two hundred seven consecutive female patients diagnosed with symptomatic paroxysmal SVT were requested to respond to multiple questionnaires before electrophysiologic study and catheter ablation. A person-years data method was used to estimate risk of first onset of paroxysmal SVT during pregnancy. Exacerbation of paroxysmal SVT was assessed by a score scale including each of the following symptoms: palpitation, fatigue, rest dyspnea, effort dyspnea, dizziness, chest oppression, blurred vision, and syncope (total score change > 2 points). In the 107 patients with accessory pathway- mediated tachycardia, 7 patients had had a first onset of tachycardia during pregnancy (relative risk ratio 0.86, confidence interval 0.4 to 1.9, p = 0.35). In the 100 patients with atrioventricular nodal reentrant tachycardia, 1 patient had had the first onset of tachycardia during pregnancy (relative risk ratio 0.11, confidence interval 0.02 to 0.56, p = 0.004). Otherwise, 14 of the 63 patients (22%) with tachycardia in the pregnant and nonpregnant periods had exacerbation of symptoms during pregnancy. Thus, first onset of paroxysmal SVT during pregnancy was rare (3.9%), and pregnancy was associated with a low risk of first onset of paroxysmal SVT. However, symptoms of paroxysmal SVT were exacerbated during pregnancy in some patients.
Institutional address: Department of Medicine National Yang-Ming University School of Medicine Taiwan Republic of China.
(REFERENCE 22 OF 63) 97439444
Strasburger JF Duffy CE Gidding SS Abnormal systemic venous Doppler flow patterns in atrial tachycardia in infants.
In: Am J Cardiol (1997 Sep 1) 80(5):640-3
ISSN: 0002-9149
Congestive heart failure due to atrial tachycardia in the neonate may be caused in part by altered preload and changes in diastolic flow characteristics. During atrial tachycardia, venous flow reversal is present. Onset of flow reversal is associated with a ventriculoatrial interval. Decreased tricuspid valve inflow mean velocity and time velocity integral, decreased diastolic duration, and delayed diastolic onset were present during tachycardia when compared with sinus rhythm.
Institutional address: Division of Cardiology The Children's Memorial Hospital Chicago Illinois 60614 USA.
(REFERENCE 23 OF 63) 94152617
Shih HT Miles WM Klein LS Hubbard JE Zipes DP Multiple accessory pathways in the permanent form of junctional reciprocating tachycardia.
In: Am J Cardiol (1994 Feb 15) 73(5):361-7
ISSN: 0002-9149
The permanent form of junctional reciprocating tachycardia (PJRT) has been successfully eliminated by ablation of the accessory pathway responsible for the tachycardia. The coexistence of multiple accessory pathways responsible for different, long RP-interval tachycardias was not documented previously. Five patients with PJRT underwent radiofrequency catheter ablation of accessory pathways. Three of 5 patients had 2 accessory pathways each: 1 had 2 left free wall accessory pathways, another had a right posterior free wall and right posteroseptal pathway, whereas the third had 2 right posteroseptal pathways approximately 1 cm apart. The remaining 2 patients each had 1 right posteroseptal accessory pathway. Seven of 8 pathways were successfully ablated with a median of 3 radiofrequency pulses. No patient developed complications. Peak serum creatine kinase ranged from 131 to 311 IU/liter, with peak MB fraction 7 to 17 IU/liter, or 5 to 11%. Follow-up electrophysiologic study, 29 to 70 days after ablation, revealed no inducible tachycardia and no evidence of accessory pathway conduction, except for the 1 pathway not ablated. All patients remained asymptomatic 17 to 29 months after ablation. Thus, patients with PJRT can have several accessory pathways that can be safely and effectively eliminated with radiofrequency catheter ablation.
Registry Numbers: 7683-59-2 (Isoproterenol)
Institutional address: Department of Medicine and Pediatrics Indiana University School of Medicine Indianapolis.
(REFERENCE 24 OF 63) 94026724
Goldberger J Kall J Ehlert F Deal B Olshansky B Benson DW Baerman J Kopp D Kadish A Wilber D Effectiveness of radiofrequency catheter ablation for treatment of atrial tachycardia.
In: Am J Cardiol (1993 Oct 1) 72(11):787-93
ISSN: 0002-9149
Catheter ablation has been used to treat atrioventricular node reentrant and atrioventricular reentrant tachycardias with extremely high success rates. The suitability of catheter ablation for treatment of atrial tachycardia, a much less common type of supraventricular tachycardia, has not been well addressed. Fifteen patients (8 females) ranging from 10 to 83 years (mean 38 +/- 22) were referred for catheter ablation of supraventricular tachycardia. The diagnosis of atrial tachycardia was established by standard electrophysiologic techniques. A combination of activation and pace mapping was used to identify a suitable site for radiofrequency current catheter ablation. Medical therapy was unsuccessful in all but 1 patient. Two patients had surgically corrected congenital heart disease, 2 had coronary artery disease and 1 had dilated cardiomyopathy. Seven patients had depressed left ventricular function. Six patients had incessant tachycardias. Presumed tachycardia mechanism was automatic in 11 patients and reentrant in 4. Mean tachycardia cycle length was 372 +/- 74 ms. Catheter ablation was acutely successful in 12 patients (80%) with application of 11.1 +/- 6.6 lesions at a mean voltage of 60 +/- 9 V. In the other 3 patients, 16 to 38 lesions were applied. At a mean follow-up of 18.5 +/- 6.5 months, 2 patients have had recurrences with different P-wave morphologies and underwent a second successful catheter ablation procedure. An additional 2 patients had recurrences with the same P- wave morphology and 1 underwent a second successful catheter ablation procedure. Thus, radiofrequency ablation can be used in a diverse population of patients with atrial tachycardia with an acute success rate of 80% and a long-term success rate of 73%.
Institutional address: Department of Medicine Northwestern University Medical School Chicago 60611.
(REFERENCE 25 OF 63) 93343098
Janousek J Paul T Reimer A Kallfelz HC Usefulness of propafenone for supraventricular arrhythmias in infants and children.
In: Am J Cardiol (1993 Aug 1) 72(3):294-300
ISSN: 0002-9149
The relation between propafenone dose, serum level, electrocardiographic parameters, antiarrhythmic drug efficacy and adverse effects was studied in 47 children with symptomatic supraventricular arrhythmias aged 1 day to 10.3 years (median 2.2 months) with a mean follow-up of 14.3 months. Propafenone trough serum levels were measured using gas chromatography. Oral propafenone (mean dose 353 mg/m2/day) was effective in 41 of the 47 patients (87.2%). Serum levels did not differ between patients responding and not responding to propafenone (0.45 +/- 0.40 vs 0.36 +/- 0.41 mg/liter). PR interval and QRS complex duration increased more significantly with propafenone dose increments (p < 0.001), than with propafenone serum levels (p < 0.05). At successful treatment PR interval and QRS complex were prolonged by a mean of 19.2 and 20.5% compared with pretreatment status. Five patients exhibited unexpected marked QRS complex prolongation (50 to 200%) despite low propafenone dosage (< 300 mg/m2/day) and level ranging from 0.05 to 1.33 mg/liter. Three patients (6.1%) were suspected of being "poor" metabolizers of propafenone. Mild chronic elevation of serum liver enzymes was observed in 5 patients treated with a larger dose (mean 448 mg/m2/day, p < 0.001). No proarrhythmia was noted on serial Holter monitors. One patient with Wolff-Parkinson-White syndrome and a normal heart had cardiac arrest after aspiration. Serial monitoring of PR interval and QRS complex duration was more useful for proper dosage adjustment than propafenone serum levels. Serum liver enzymes should be closely monitored when using higher propafenone doses. Malignant proarrhythmia could not be excluded in the 1 patient with cardiac arrest.
Registry Numbers: 54063-53-5 (Propafenone)
Institutional address: Department of Pediatric Cardiology Children's Hospital Hannover Germany.
*****AMERICAN JOURNAL OF DISEASES OF CHILDREN*****
(REFERENCE 26 OF 63) 93282382
Mehta AV Rhabdomyoma and ventricular preexcitation syndrome. A report of two cases and review of literature.
In: Am J Dis Child (1993 Jun) 147(6):669-71
ISSN: 0002-922X
OBJECTIVE--A description of two infants with ventricular preexcitation syndrome and supraventricular tachycardia associated with rhabdomyoma and review of the literature. DESIGN--A review of two patients who were seen between 1981 and 1986 in the cardiology department. SETTING--Pediatric Heart Institute at St Christopher's Hospital for Children, Philadelphia, Pa. PARTICIPANTS--Two newborn female infants with ventricular preexcitation syndrome, supraventricular tachycardia, rhabdomyomatous tumor of the heart, and tuberous sclerosis are described. RESULTS--The first patient had unsuccessful partial resection of the rhabdomyomatous tumors obstructing the tricuspid valve and right ventricular cavity and died immediately after surgery. By histologic examination, no direct accessory connection was noted between the myocardial fibers of atria and ventricles through annulus fibrosus. By gross examination, the tumor extended from the right atrium through the tricuspid valve to the right ventricular cavity, suggestive of macroscopic accessory connection. The second patient presented with unsustained ventricular tachycardia and obstructive subaortic rhabdomyoma, requiring emergency surgery. One week later, reentrant supraventricular tachycardia developed and she required digoxin therapy for 15 months. CONCLUSIONS--Infants with rhabdomyomatous tumor of the heart and ventricular preexcitation syndrome may have microscopic or macroscopic accessory connections. Cardiac tumors like rhabdomyoma and oncocytic tumors should be suspected in infants with ventricular preexcitation syndrome or supraventricular tachycardia.
Institutional address: Department of Pediatrics James H. Quillen College of Medicine East Tennessee State University Johnson City 37614-0578.
*****ANESTHESIOLOGY*****
(REFERENCE 27 OF 63) 95233606
Lavoie J Walsh EP Burrows FA Laussen P Lulu JA Hansen DD Effects of propofol or isoflurane anesthesia on cardiac conduction in children undergoing radiofrequency catheter ablation for tachydysrhythmias.
In: Anesthesiology (1995 Apr) 82(4):884-7
ISSN: 0003-3022
BACKGROUND: To determine suitability for ablation procedures in children, two commonly used anesthetic agents were studied: propofol and isoflurane. METHODS: Twenty patients presenting for a radiofrequency catheter ablation procedure were included and randomly assigned to two groups. A baseline electrophysiology study was performed during anesthesia with thiopental, alfentanil, nitrous oxide, and pancuronium in all patients. At the completion of the baseline electrophysiology study (EPS), 0.8-1.2% isoflurane was administered to patients in group 1 and 2 mg/kg propofol bolus plus an infusion of 150 micrograms.kg-1.min-1 was administered to patients in group 2. Nitrous oxide and pancuronium were used throughout the procedure. After 30 min of equilibration, both groups underwent a repeat EPS. The following parameters were measured during the EPS: cycle length, atrial-His interval, His-ventricle interval, corrected sinus node recovery time, AV node effective refractory period, and atrial effective refractory period. Using paired t tests, the electrophysiologic parameters described above measured during propofol or isoflurane anesthesia were compared to those measured during baseline anesthesia. Statistical significance was accepted as P < 0.05. RESULTS: There was no statistically significant difference in the results obtained during baseline anesthesia when compared with those measured during propofol or isoflurane anesthesia. CONCLUSIONS: Neither propofol nor isoflurane anesthesia alter sinoatrial or atrioventricular node function in pediatric patients undergoing radiofrequency catheter ablation, compared to values obtained during baseline anesthesia with alfentanil and midazolam.
Registry Numbers: 2078-54-8 (Propofol) 26675-46-7 (Isoflurane)
Institutional address: Department of Anesthesia Children's Hospital Boston MA 02115 USA.
*****ANNALS OF EMERGENCY MEDICINE*****
(REFERENCE 28 OF 63) 96374194
Friedman FD Intraosseous adenosine for the termination of supraventricular tachycardia in an infant.
In: Ann Emerg Med (1996 Sep) 28(3):356-8
ISSN: 0196-0644
In recent years, the intraosseous technique has dramatically improved the speed at which vascular access may be achieved in critically ill children, and adenosine has been shown to rapidly convert supraventricular tachycardia to normal sinus rhythm. Until now, no report has demonstrated that this drug may be effectively given by this route in human beings. This case report describes the successful termination of supraventricular tachycardia in an infant with the intraosseous administration of adenosine.
Registry Numbers: 58-61-7 (Adenosine)
Institutional address: Department of Emergency Medicine New England Medical Center Boston Massachusetts USA. franklin.friedman@es.nemc.org
(REFERENCE 29 OF 63) 96094834
Lozano M Jr McIntosh BA Giordano LM Effect of adenosine on the management of supraventricular tachycardia by urban paramedics.
In: Ann Emerg Med (1995 Dec) 26(6):691-6
ISSN: 0196-0644
STUDY OBJECTIVE: To determine the effect of the addition of adenosine, as a standing-order medication, on the prehospital management of supraventricular tachycardia (SVT) in a large urban emergency medical services (EMS) system. DESIGN: Prospective observational case series with historical controls. SETTING: Large urban municipal EMS system staffed by paramedics and emergency medical technicians trained to operate automatic or semiautomatic defibrillators (EMT-Ds). PARTICIPANTS: We observed a consecutive sample of prehospital patients who presented with an initial ECG rhythm of SVT, as interpreted by the treating paramedics, between July 1 and December 31, 1993. We used patients from the same 6-month period in 1992 as our control group. Indications for treatment were chest pain, evidence of myocardial ischemia, or shock. Adenosine had been introduced as a first-line medication to be used under standing orders in cases of unstable SVT before a physician was contacted for medical control options. RESULTS: We studied 239 cases and 228 controls. Acceptable call reports with pretreatment and posttreatment ECGs were available for 140 (59%) of the study cases and 104 (46%) of the controls. The two groups were similar in terms of age, sex, and initial vital signs. In the control group, 75 patients had indications for treatment, and 16 were treated (21%). In the study group, 127 had indications for treatment and 103 (81.1%) were treated (odds ratio, 15.83; 95% confidence interval, 7.38-34.4). CONCLUSION: The introduction of adenosine as a standing-order medication into an urban EMS system increased the proportion of patients who received advanced life support treatment. Paramedics were able to accurately diagnose and begin treatment of SVT with adenosine without direct medical supervision.
Registry Numbers: 58-61-7 (Adenosine)
Institutional address: Section of Emergency Medicine Bayfront Medical Center St. Petersburg Florida USA.
(REFERENCE 30 OF 63) 94311526
Cook P Scarfone RJ Cook RT Adenosine in the termination of albuterol-induced supraventricular tachycardia [published erratum appears in Ann Emerg Med 1995 Jan;25(1):119]
In: Ann Emerg Med (1994 Aug) 24(2):316-9
ISSN: 0196-0644
Five percent of children in the United States have asthma. Status asthmaticus is one of the most common conditions for which children seek care in a pediatric emergency department. beta 2-Agonists such as albuterol are the mainstay of emergency therapy for such children. We present a case of a 4-year-old boy who experienced supraventricular tachycardia (SVT) following albuterol therapy. This is believed to be the first report of adenosine being successfully used to treat a child with albuterol-induced SVT. We also briefly review the recognition and management of SVT in children and the pharmacokinetics of and indications for adenosine.
Registry Numbers: 18559-94-9 (Albuterol) 58-61-7 (Adenosine)
Institutional address: Department of Emergency Medicine Memorial Hospital York.
*****ARCHIVES OF PEDIATRICS AND ADOLESCENT MEDICINE*****
(REFERENCE 31 OF 63) 97236015
Lashus AG Case CL Gillette PC Catheter ablation treatment of supraventricular tachycardia-induced cardiomyopathy.
In: Arch Pediatr Adolesc Med (1997 Mar) 151(3):264-6
ISSN: 1072-4710
OBJECTIVE: To investigate the efficacy of radiofrequency catheter ablation (RFCA) as an alternative nonpharmacological therapy for tachycardia-induced cardiomyopathy. DESIGN: A retrospective study of 8 pediatric patients (age range, 10 months to 21 years) who underwent RFCA for an incessant supraventricular tachycardia-induced cardiomyopathy. A patient's tachycardia was considered incessant if the tachycardia was present more than 75% of the time. The left ventricular shortening fraction, as measured by echocardiography, before and after ablation, was used as the index of cardiac function. Cardiomyopathy was defined as a left ventricular shortening fraction of 28% or less. RESULTS: Following RFCA, 7 patients had total resolution of their tachycardia and were discharged from the hospital with no antiarrhythmic medications. The remaining patient's tachycardia was modified by the catheter ablation and was subsequently controlled with flecainide acetate. With follow-up ranging from 9 months to 3 years, all patients have normal cardiac function as documented by echocardiography. No significant morbidity resulted from the catheter ablations. CONCLUSIONS: Tachycardia- induced cardiomyopathy is amenable to "curative" therapy with RFCA. Ventricular function returns to normal after the successful catheter ablation procedure.
Institutional address: South Carolina Children's Heart Center Medical University of South Carolina Charleston USA.
*****BRITISH HEART JOURNAL*****
(REFERENCE 32 OF 63) 96046388
Sanchez C Benito F Moreno F Reversibility of tachycardia-induced cardiomyopathy after radiofrequency ablation of incessant supraventricular tachycardia in infants.
In: Br Heart J (1995 Sep) 74(3):332-3
ISSN: 0007-0769
Tachycardia-induced cardiomyopathy developed in a 3 month old infant with permanent junctional reciprocating tachycardia, which was incessant despite medical treatment. The patient underwent transcatheter radiofrequency ablation. There were no complications and 8 months after the procedure the patient was symptom free without medication.
Institutional address: Department of Pediatric Cardiology Hospital Infantil La Paz Madrid Spain.
(REFERENCE 33 OF 63) 93213642
Connelly DT de Belder MA Cunningham D Lopes AN Rickards AF Rowland E Long-term follow up of patients treated with a software based antitachycardia pacemaker.
In: Br Heart J (1993 Mar) 69(3):250-4
ISSN: 0007-0769
INTRODUCTION--Over the past decade, several advances have been made in the management of tachycardias by pacing techniques, but limited data are available on the long-term outcome of patients treated with antitachycardia pacemakers. PATIENTS AND METHODS--An antitachycardia pacemaker, the Intermedics Intertach, was implanted in 22 (17 female) patients with supraventricular tachycardia over a five year period. All were selected after detailed evaluation and testing of a temporary antitachycardia pacemaker system showed that their arrhythmia could be stopped promptly, reliably, and under different physiological conditions. RESULTS--The 22 patients have been followed up for a mean period of 57.3 (range 19-76) months. All except one of the patients has had frequent episodes of tachycardia reliably ended by the pacemaker. Complications have occurred in seven patients, necessitating removal of the pacing system in four. Of the 18 patients who continue to have pacemakers, seven are being treated with beta blockers or verapamil; no other antiarrhythmic drugs are being taken. CONCLUSIONS--Antitachycardia pacing is an acceptable long-term option for carefully selected patients with supraventricular tachycardia, but even after extensive testing a substantial number of the patients may continue to require drug treatment. Furthermore, the widespread use of curative techniques for supraventricular arrhythmias (catheter ablation and surgery) has decreased the need for this palliative treatment.
Institutional address: Royal Brompton National Heart and Lung Hospital London.
*****CIRCULATION*****
(REFERENCE 34 OF 63) 98015977
Tai CT Chen SA Chiang CE Lee SH Ueng KC Wen ZC Huang JL Chen YJ Yu WC Feng AN Chiou CW Chang MS Characterization of low right atrial isthmus as the slow conduction zone and pharmacological target in typical atrial flutter.
In: Circulation (1997 Oct 21) 96(8):2601-11
ISSN: 0009-7322
BACKGROUND: Previous electrophysiological studies in patients with typical atrial flutter suggested that the slow conduction zone might be located in the low right atrial isthmus, which is a path formed by orifice of inferior vena cava, eustachian valve/ridge, coronary sinus ostium, and tricuspid annulus. The conduction characteristics during atrial pacing and responses to antiarrhythmic drugs of this anatomic isthmus were unknown. METHODS AND RESULTS: Forty-four patients, 20 patients with paroxysmal supraventricular tachycardia (group 1) and 24 patients with clinically documented paroxysmal typical atrial flutter (group 2), were studied. A 20-pole halo catheter was situated around the tricuspid annulus. Incremental pacing from the low right atrium and coronary sinus ostium was performed to measure the conduction time and velocity along the isthmus and lateral wall in the baseline state and after intravenous infusion of procainamide or sotalol. In both groups, conduction velocity in the isthmus during incremental pacing was significantly lower than that in the lateral wall before and after infusion of antiarrhythmic drugs. Furthermore, gradual conduction delay with unidirectional block in the isthmus was relevant to initiation of typical atrial flutter. Compared with group 1, group 2 had a lower conduction velocity in the isthmus and shorter right atrial refractory period. Procainamide significantly decreased the conduction velocity, but sotalol did not change it. In contrast, sotalol significantly prolonged the atrial refractory period with a higher extent than procainamide. After infusion of procainamide, the increase of conduction time in the isthmus accounted for 52+/-19% of the increase in flutter cycle length, and 5 of 12 patients (42%) had spontaneous termination of typical flutter. After infusion of sotalol, typical flutter was induced in only 6 of 12 patients (50%) without significant prolongation of flutter cycle length. CONCLUSIONS: The low right atrial isthmus with rate-dependent slow conduction properties is critical to initiation of typical human atrial flutter. It may be the potentially pharmacological target of antiarrhythmic drugs in the future.
Registry Numbers: 3930-20-9 (Sotalol) 51-06-9 (Procainamide)
Institutional address: Department of Medicine National Yang-Ming University School of Medicine Veterans General Hospital-Taipei and Kaoshiung Taiwan ROC.
(REFERENCE 35 OF 63) 95361136
Doig JC Saito J Harris L Downar E Coronary sinus morphology in patients with atrioventricular junctional reentry tachycardia and other supraventricular tachyarrhythmias.
In: Circulation (1995 Aug 1) 92(3):436-41
ISSN: 0009-7322
BACKGROUND: Coronary sinus access by electrode catheters is easier in patients with atrioventricular junctional reentry tachycardia (AVJRT) than in patients with other supraventricular tachyarrhythmias. The reason for this has not been addressed. METHODS AND RESULTS: The size and shape of the proximal coronary sinus were measured in 15 patients with AVJRT and 14 control subjects after angiographic visualization. Coronary sinus dimensions, morphology, and angle of origin from the right atrium were measured. The proximal coronary sinus in patients with AVJRT was larger than in the control population. The mean ostium diameter was 12.2 +/- 2 mm compared with control dimensions of 8.5 +/- 1.5 mm, P = .00001. At a distance of 5 mm from the ostium, the coronary sinus measured 10.2 +/- 1.8 mm compared with 8.1 +/- 1.9 mm, P = .007. The dilatation persisted 10 mm into the coronary sinus, with a measurement of 9 +/- 1.4 mm compared with 7.6 +/- 2 mm, P = .04. In 73% of AVJRT patients, the proximal coronary sinus had the appearance of a wind sock. This morphology was seen only in 7% of control patients, in whom the coronary sinus was tubular (in 93%). There was considerable interindividual variability in the angle of origin. CONCLUSIONS: The proximal coronary sinus in patients with AVJRT was significantly different from a control population. The ostium was 44% larger and remained more dilated to at least 10 mm from the ostium. The appearance was like a wind sock in AVJRT patients and tubular in the control patients. These findings may have important implications for arrhythmia pathogenesis in such patients.
Institutional address: Department of Medicine Toronto Hospital (General Division) Ontario Canada.
(REFERENCE 36 OF 63) 95008111
Chiang CE Chen SA Wu TJ Yang CJ Cheng CC Wang SP Chiang BN Chang MS Incidence, significance, and pharmacological responses of catheter- induced mechanical trauma in patients receiving radiofrequency ablation for supraventricular tachycardia.
In: Circulation (1994 Oct) 90(4):1847-54
ISSN: 0009-7322
BACKGROUND: Catheter-induced mechanical trauma is unfavorable during electrophysiological study. However, its incidence, significance, and pharmacological responses in patients receiving radiofrequency ablation for supraventricular tachycardia have not been investigated. METHODS AND RESULTS: A prospective study was performed in 666 consecutive patients with documented, symptomatic supraventricular tachycardia. All had been referred for electrophysiological study and radiofrequency ablation. Catheter-induced mechanical trauma was defined by either disappearance of or change in preexcitation pattern induced by the electrode catheters or noninducibility of tachycardia after the electrode catheter-induced termination of tachycardia, confirmed by electrophysiological study. Adenosine, isoproterenol, and atropine were serially administered 1 hour after the mechanical trauma to study pharmacological response. "Rescue" radiofrequency ablation was defined as delivery of radiofrequency energy just at the presumed ablation site immediately after the mechanical trauma. Of the 666 patients, 254 had atrioventricular (AV) nodal reentrant tachycardia, 367 patients had accessory pathways, 30 patients had atrial tachycardia, and 15 had atrial flutter. Catheter-induced mechanical trauma occurred in 17 patients (2.6%): 4 patients had AV nodal reentrant tachycardia, 9 had accessory pathways, and 4 had atrial tachycardia. Five patients had such episodes during the placement of electrode catheters and 12, during mapping and ablation procedures. Of the 4 patients with AV nodal reentrant tachycardia, 3 had mechanical trauma on the retrograde fast pathway and 1, on the antegrade slow pathway. In the 9 patients with accessory pathways, those pathways were located in the left free wall in 4 patients, right free wall in 1, right posteroseptum in 1, and right anteroseptum in 3. Atrial tachycardia was more easily traumatized than AV nodal reentrant tachycardia (P < .01) and than accessory pathways (P < .01). The clinical courses of mechanical trauma were variable: 1 patient had spontaneous recovery within 1 week, 5 patients had recurrence of tachycardia within 3 months, and the rest have been free of tachycardia from 3 to 35 months. The recurrence rate was higher in patients with mechanical trauma than in those without (33.3% versus 3.5%, P < .0001) despite rescue radiofrequency ablation given in 7 patients. Pharmacological agents were generally unable to revive the traumatized tissues, and recurrence was unpredictable. CONCLUSIONS: Catheter-induced mechanical trauma was not common in patients receiving radiofrequency ablation for supraventricular tachycardia. Their clinical courses were variable, and pharmacological manipulation offered little assistance. More than half of the patients had long-term cures. However, the recurrence rate was, on the whole, significantly high despite rescue radiofrequency ablation. There is a need for great caution in the placement of electrode catheters in every patient during electrophysiological study and radiofrequency ablation.
Registry Numbers: 58-61-7 (Adenosine) 7683-59-2 (Isoproterenol)
Institutional address: Department of Medicine National Yang-Ming Medical College Taipei Taiwan ROC.
(REFERENCE 37 OF 63) 98409523
Durongpisitkul K Porter CJ Cetta F Offord KP Slezak JM Puga FJ Schaff HV Danielson GK Driscoll DJ Predictors of early- and late-onset supraventricular tachyarrhythmias after Fontan operation.
In: Circulation (1998 Sep 15) 98(11):1099-107
ISSN: 0009-7322
BACKGROUND: The objectives of our study were to determine the frequency of supraventricular tachyarrhythmias (SVTAs) among modifications of the Fontan operation and identify risk factors for developing SVTA. METHODS AND RESULTS: The population consisted of all patients who had any modification of the Fontan operation at the Mayo Clinic between 1985 and 1993. Clinically significant SVTAs were those requiring initiation or change of antiarrhythmic treatment, and they were divided into early SVTAs (<30 days after the operation) and late SVTAs (>/=30 days after the operation). Clinical histories were reviewed, and health status questionnaires were sent. Four hundred ninety-nine patients had various modifications of the Fontan operation. Frequency of early SVTA was 15%. Risk factors identified by multivariate analysis for early SVTA were AV valve regurgitation, abnormal AV valve, and preoperative SVTA. Frequency of late SVTA was 6% by 1 year, 12% by 3 years, and 17% by 5 years. Risk factors for late SVTA were age at operation (<3 or >/=10 years) and systemic AV valve replacement. By univariate and multivariate analysis, the type of Fontan operation was not a significant risk factor for late SVTA when all 6 modifications were considered. However, when we analyzed the frequency of late SVTA for the 2 recently used modifications, we found a lower frequency of late SVTA in patients with atriopulmonary connection with lateral tunnel compared with those with total cavopulmonary connection. CONCLUSIONS: Postoperative SVTA continues to be a significant problem. Risk factors for SVTA are AV valve regurgitation, abnormal AV valve, preoperative SVTA, and age at operation. Frequency of SVTA does not appear to be related to type of Fontan procedure except for slightly lower frequency in patients with atriopulmonary connection with lateral tunnel compared with those with total cavopulmonary connection.
Institutional address: From the Section of Pediatric Cardiology Section of Biostatistics and the Division of Thoracic and Cardiovascular Surgery Mayo Clinic and Mayo Foundation Rochester MN 55905 USA.
(REFERENCE 38 OF 63) 96382178
Hirao K Otomo K Wang X Beckman KJ McClelland JH Widman L Gonzalez MD Arruda M Nakagawa H Lazzara R Jackman WM Para-Hisian pacing. A new method for differentiating retrograde conduction over an accessory AV pathway from conduction over the AV node.
In: Circulation (1996 Sep 1) 94(5):1027-35
ISSN: 0009-7322
BACKGROUND: Differentiation between ventriculoatrial (VA) conduction over an accessory AV pathway (AP) and the AV node (AVN) may be difficult, especially in patients with a septal AP. METHODS AND RESULTS: A new pacing method, para-Hisian pacing, was tested in 149 patients with AP and 53 patients without AP who had AV nodal reentrant tachycardia (AVNRT). Ventricular pacing was performed adjacent to the His bundle and proximal right bundle branch (HB-RB), initially at high output to capture both RV and HB-RB. The output was then decreased to lose HB-RB capture. The change in timing and sequence of retrograde atrial activation between HB-RB capture and noncapture was examined. Loss of HB-RB capture without change in stimulus-atrial (S-A) interval or atrial activation sequence indicated exclusive retrograde AP conduction. An increase in S-A interval without change in His bundle-atrial interval or atrial activation sequence indicated exclusive retrograde AVN conduction. A change in atrial activation sequence indicated the presence of both retrograde AP and AVN conduction. Para-Hisian pacing correctly identified retrograde AP conduction in 132 of 147 AP patients, including all septal and right free wall APs. Retrograde AVN conduction masked AP conduction in 9 of 34 patients with a left free wall AP and 6 of 9 patients with the permanent form of junctional reciprocating tachycardia. Para-Hisian pacing correctly excluded AP conduction in all 53 patients with AVNRT. CONCLUSIONS: Para-Hisian pacing reliably identifies retrograde conduction over septal and right free wall APs, but AVN conduction may mask APs located far from the pacing site or with a long retrograde conduction time.
Institutional address: Department of Medicine University of Oklahoma Health Sciences Center Oklahoma City 73104 USA.
(REFERENCE 39 OF 63) 96156010
Kalman JM VanHare GF Olgin JE Saxon LA Stark SI Lesh MD Ablation of 'incisional' reentrant atrial tachycardia complicating surgery for congenital heart disease. Use of entrainment to define a critical isthmus of conduction.
In: Circulation (1996 Feb 1) 93(3):502-12
ISSN: 0009-7322
BACKGROUND: Intra-atrial reentrant tachycardia occurs frequently after surgery for congenital heart disease and is difficult to treat. We tested the hypotheses that intra-atrial reentrant tachycardia in patients who had undergone prior reparative surgery for congenital heart disease could be successfully ablated by targeting a protected isthmus of conduction bounded by natural and surgically created barriers and that entrainment techniques could be used to identify these zones. METHODS AND RESULTS: Eighteen consecutive patients with 26 intra-atrial reentrant tachycardias complicating surgery for congenital heart disease (9 atrial septal defect repair, 4 Fontan, 2 Mustard, 2 Senning, and 1 Rastelli procedure) underwent electrophysiological study and ablation attempts. Mapping of activation was facilitated by the deployment of catheters with multiple electrodes. Sites for ablation were sought that demonstrated entrainment with concealed fusion and at which the postpacing interval minus the tachycardia cycle length and the stimulus to P wave minus the activation time were < 30 ms. These sites were considered to be within a narrow isthmus critical to the tachycardia mechanism. Anatomic barriers bordering the critical isthmus of conduction were identified on anatomic grounds, by the presence of areas of electrical silence or by the demonstration of split potentials signifying a line of block. Success was achieved in 15 patients with 21 arrhythmias. The median number of radiofrequency applications was 5. There was a wide range of activation times at successful sites (-30 to -250 ms). At a mean duration of follow-up of 17 +/- 8 months, 11 patients were asymptomatic and 9 did not require antiarrhythmia therapy. CONCLUSIONS: Successful ablation of intra- atrial reentrant tachycardia complicating surgery for congenital heart disease may be achieved by creation of an ablative lesion in a critical isthmus of conduction bounded by anatomic barriers. This isthmus may be identified by the presence of entrainment with concealed fusion and an analysis of the relationship between the postpacing interval and the tachycardia cycle length and between the activation time and the stimulus time. Because this isthmus is invariably confined on at least one aspect by a surgical repair site that is of central importance to the tachycardia mechanism, we suggest that this type of arrhythmia be given the descriptive designation of "incisional reentry."
Institutional address: Department of Medicine University of California San Francisco 94143-1354 USA.
(REFERENCE 40 OF 63) 96069275
A randomized, placebo-controlled trial of propafenone in the prophylaxis of paroxysmal supraventricular tachycardia and paroxysmal atrial fibrillation. UK Propafenone PSVT Study Group.
In: Circulation (1995 Nov 1) 92(9):2550-7
ISSN: 0009-7322
BACKGROUND: Few antiarrhythmic agents have been shown in randomized controlled trials to be effective and well tolerated in the prophylaxis of paroxysmal supraventricular tachycardia or paroxysmal atrial fibrillation. Propafenone, a class IC anti-arrhythmic agent with weak beta-adrenoceptor antagonist properties, has shown promise in preliminary clinical studies. METHODS AND RESULTS: A double-blind, placebo-controlled trial of the efficacy and tolerability of propafenone was undertaken in 100 patients with paroxysmal supraventricular tachycardia ([PSVT] n = 52) or atrial fibrillation/flutter ([PAF] n = 48) who had recorded two or more symptomatic arrhythmia recurrences by transtelephonic ECG monitoring during a 3-month drug-free observation period. Patients were randomized into two consecutive crossover periods of propafenone (300 mg BID) versus placebo followed by 300 mg TID propafenone versus placebo. Analysis was based on the time to treatment failure, defined as the interval from treatment onset to the occurrence of either ECG- documented arrhythmia or an intolerable adverse event. With a proportional-hazards model, we determined the relative risk (95% confidence interval) of treatment failure after the achievement of steady-state drug levels for placebo compared with propafenone 300 mg BID to be 6.8 (2.2 to 21.2, P < .001, n = 45) for PSVT and 6.0 (1.8 to 20.0, P = .004, n = 30) for PAF. Due to a greater incidence of adverse events on high-dose propafenone, the relative risks of receiving placebo rather than propafenone 300 TID were only 2.2 (0.9 to 5.3, P = .1, n = 34) for PSVT and 1.9 (0.7 to 4.7, P = .2, n = 25) for PAF. However, if adverse events were excluded in the high-dose comparison, relative risks for arrhythmia recurrence were 15.0 (2.0 to 113, P = .009) for PSVT and incalculable (no preferences for placebo, P = .0002) for PAF. One episode of wide-complex tachycardia was documented during propafenone therapy. CONCLUSIONS: Propafenone is of value in the prophylaxis of both PSVT and PAF. A dose of 300 mg BID is effective and well tolerated. A larger dose of 300 mg TID causes more adverse effects but may be more effective in those who can tolerate it.
Registry Numbers: 54063-53-5 (Propafenone)
(REFERENCE 41 OF 63) 94074070
Ormaetxe JM Almendral J Arenal A Martinez-Alday JD Pastor A Villacastin JP Delcan JL Ventricular fusion during resetting and entrainment of orthodromic supraventricular tachycardia involving septal accessory pathways. Implications for the differential diagnosis with atrioventricular nodal reentry.
In: Circulation (1993 Dec) 88(6):2623-31
ISSN: 0009-7322
BACKGROUND. Ventricular fusion during transient entrainment of orthodromic atrioventricular reciprocating tachycardias (OAVRT) was originally found to be absent and recently observed only with left ventricular stimulation. However, previous studies were restricted to cases with a left free wall accessory pathway. The hypothesis of the present study was that fusion is likely during resetting and entrainment of OAVRT with right ventricular stimulation if the accessory pathway is septally located, since its insertion is relatively close to the stimulation site. This phenomenon can help in the differential diagnosis with atrioventricular nodal reentry (AVNR). METHODS AND RESULTS. We performed programmed right ventricular stimulation during regular inducible supraventricular tachycardia with concentric atrial activation in 44 patients--20 with OAVRT and 24 with AVNR. Fusion in the ECG morphology of extrastimuli producing resetting was observed in 19 of 19 OAVRT but in 0 of 11 AVNR reset (P < .001). Transient entrainment was demonstrated in all 31 cases undergoing rapid ventricular pacing (14 OAVRT and 17 AVNR). Entrainment with fusion occurred in 13 of 14 OAVRT and in 0 of 17 AVNR (P < .001). Fusion was critically dependent on the coupling intervals or pacing rates, sometimes having a narrow window for its observation. CONCLUSIONS. The relative proximity (conduction time) among pacing site, site of entrance to a reentrant circuit, and site of exit from the circuit to the paced chamber are critical for the occurrence of fusion during resetting and/or entrainment. The presence or absence of fusion during these phenomena can help in the differential diagnosis of certain supraventricular tachycardias.
Institutional address: Clinical Electrophysiology Laboratory Hospital General Gregorio Mara~on Madrid Spain.
*****HEART*****
(REFERENCE 42 OF 63) 97221348
Balaji S Lau YR Gillette PC Effect of heart rate on QT interval in children and adolescents.
In: Heart (1997 Feb) 77(2):128-9
ISSN: 1355-6037
OBJECTIVE: To study the effect of sympathetic stimulation and increase in heart rate on the QT and QTc intervals. DESIGN: Prospective non-randomised study of eight consecutive patients. SETTING: Electrophysiology laboratory at a tertiary centre. PATIENTS: Eight patients aged 10-20 years (median 12.5) undergoing repeat electrophysiological study after previously successful catheter ablation (n = 6) or presumed supraventricular tachycardia (n = 2) with negative studies. INTERVENTIONS: Electrocardiograms were obtained (a) at baseline, (b) during atrial pacing at 450 ms cycle length, (c) during isoprenaline infusion at 0.025 microgram/kg/min, (d) adding atrial pacing (450 ms cycle length) to isoprenaline at 0.025 microgram/kg/min, and (e) isoprenaline at 0.05 microgram/kg/min. MAIN OUTCOME MEASURES: QT and QTc intervals at each of the above mentioned stages. RESULTS: The QT interval was reduced from a mean value of 350 ms to around 315-325 ms by each of the above manoeuvres. Correspondingly, the QTc increased from a mean of 407 ms to around 445-470 ms. Pacing was as effective as isoprenaline in shortening the QT interval and prolonging the QTc intervals. CONCLUSIONS: Heart rate directly influences QT and QTc intervals in children and adolescents. The QT is shortened, but QTc is prolonged. Hence, reliance on the QTc alone could lead to mistaken diagnosis of long QT syndrome.
Registry Numbers: 7683-59-2 (Isoproterenol)
Institutional address: South Carolina Children's Heart Center Medical University of South Carolina Charleston 29425 USA.
(REFERENCE 43 OF 63) 97467814
Benito F Sanchez C Radiofrequency catheter ablation of accessory pathways in infants.
In: Heart (1997 Aug) 78(2):160-2
ISSN: 1355-6037
OBJECTIVE: To evaluate the indications, results and complications of radiofrequency catheter ablation in small infants with supraventricular tachycardia due to an accessory atrioventricular pathway. METHODS: Five infants less than 9 months old underwent radiofrequency catheter ablation of accessory pathways. Ablation was done for medically refractory tachyarrhythmia associated with aborted sudden death in two patients, left ventricular dysfunction in one, failure of antiarrhythmic drugs in one, and planned cardiac surgery in one. All five patients underwent a single successful procedure. Three left free wall pathways were ablated by transseptal approach, a right posteroseptal pathway was ablated from the inferior vena cava, and a left posteroseptal pathway was approached from the inferior vena cava into the coronary sinus. A deflectable 5F bipolar electrode catheter with a 3 mm tip was used. RESULTS: A sudden increment in impedance indicative of coagulum formation was observed in two procedures. One patient developed a transient ischaemic complication after ablation of a left lateral accessory pathway by transseptal approach. This patient had mild pericardial effusion after the procedure. Moderate pericardial effusion was also noted in another patient. After a mean follow up of 18.4 months all patients are symptom free without treatment. CONCLUSIONS: Radiofrequency catheter ablation can be performed successfully in infants. Temperature monitoring in 5F ablation catheters would be desirable to prevent the development of coagulum. Echocardiography must be performed after the ablation procedure to investigate pericardial effusion.
Institutional address: Department of Paediatric Cardiology Hospital Infantil La Paz Madrid Spain.
*****HEART AND LUNG*****
(REFERENCE 44 OF 63) 98152901
Bakshi F Barzilay Z Paret G Adenosine in the diagnosis and treatment of narrow complex tachycardia in the pediatric intensive care unit.
In: Heart Lung (1998 Jan-Feb) 27(1):47-50
ISSN: 0147-9563
The ideal pharmacologic treatment for the management of children with paroxysmal supraventricular tachycardia in the perioperative period has not been defined. In this report we describe our experience using adenosine diagnostically and therapeutically in the pediatric intensive care unit, and summarize the practical aspects of its use at the perioperative period.
Registry Numbers: 58-61-7 (Adenosine)
Institutional address: Pediatric ICU Chaim Sheba Medical Center Tel Hashomer Israel.
*****JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY*****
(REFERENCE 45 OF 63) 98412557
Wu MH Wang JK Lin JL Lai LP Lue HC Young ML Hsieh FJ Supraventricular tachycardia in patients with right atrial isomerism.
In: J Am Coll Cardiol (1998 Sep) 32(3):773-9
ISSN: 0735-1097
OBJECTIVES: To clarify the prevalence and mechanism of supraventricular tachycardia in patients with right atrial isomerism. BACKGROUND: Paired SA and dual atrioventricular (AV) nodes have been described in patients with right atrial isomerism. However, the clinical significance remains unclear. METHODS: From 1987 to 1996, a total of 101 patients (61 male, 40 female) and four fetuses were identified with right atrial isomerism. The diagnosis of supraventricular tachycardia exclude the tachycardia with prolonged QRS duration or AV dissociation, and primary atrial tachycardia. RESULTS: The median follow-up duration was 38 months (range 0.2-270 months). Supraventricular tachycardia was documented in 25 patients (24.8%) and one fetus (25%) (onset age ranged from prenatal to 14 years old; median 4 years old). Actuarial Kaplan-Meier analysis revealed that the probability of being free from tachycardia was 67% and 50% at 6 and 10 years of age, respectively. These tachycardias could be converted by vagal maneuvers in one, verapamil in seven, propranolol in four, digoxin in two, procainamide in one, and rapid pacing in five. Spontaneous conversion was noted in six (including the fetus). Seven cases had received electrophysiological studies. Reciprocating AV tachycardia could be induced in five and echo beats in one. The tachycardia in three patients was documented as incorporating a posterior AV node (antegrade) and an anterior or a lateral AV node (retrograde). Two of them received radiofrequency ablation. Successful ablation in both was obtained by delivering energy during tachycardia, aimed at the earliest retrograde atrial activity and accompanied by junctional ectopic rhythm. The patient with echo beats developed tachycardia soon after operation. CONCLUSIONS: Supraventricular tachycardia is common in patients with right atrial isomerism and can occur during the prenatal stage. Drugs to slow conduction through the AV node may help to terminate the tachycardia. Radiofrequency ablation is a safe and effective treatment alternative to eliminate tachycardia.
Institutional address: Department of Pediatrics National Taiwan University Taipei. mhwu@ha.mc.ntu.edu.tw
(REFERENCE 46 OF 63) 95318353
Samson RA Deal BJ Strasburger JF Benson DW Jr Comparison of transesophageal and intracardiac electrophysiologic studies in characterization of supraventricular tachycardia in pediatric patients.
In: J Am Coll Cardiol (1995 Jul) 26(1):159-63
ISSN: 0735-1097
OBJECTIVES. This study sought to determine the accuracy of transesophageal electrophysiologic studies in diagnosing and characterizing various mechanisms of supraventricular tachycardia in pediatric patients. BACKGROUND. Transesophageal electrophysiologic studies are a relatively noninvasive means of characterizing supraventricular tachycardia. Although widely used, to our knowledge no data exist that directly compare information obtained from transesophageal electrophysiologic studies with that from intracardiac electrophysiologic studies. METHODS. We reviewed the records of 57 pediatric patients undergoing both transesophageal and intracardiac electrophysiologic studies at our institution. The results of these studies were compared with respect to mechanism of tachycardia, localization of accessory atrioventricular (AV) connections (if present) and characterization of anterograde accessory connection conduction properties. RESULTS. Tachycardia mechanisms were concordant in 56 of 57 patients: orthodromic reciprocating tachycardia in 43, antidromic reciprocating tachycardia in 1, both orthodromic and antidromic tachycardia in 2, AV node reentrant tachycardia in 5, atrial reentrant tachycardia in 4 and ectopic atrial tachycardia in 2. Of 29 patients with orthodromic reciprocating tachycardia using a concealed accessory connection, transesophageal study predicted the accessory connection site through changes induced by transient bundle branch block in 12. By the Bland- Altman method in 14 patients with pre-excitation, the anterograde accessory connection effective refractory period determined by transesophageal study compared favorably with that determined by intracardiac study (mean difference 5.0 ms, limits of agreement -55 and 65 ms). CONCLUSIONS. Transesophageal electrophysiologic studies are a highly accurate means of diagnosing and characterizing various mechanisms of supraventricular tachycardia in pediatric patients.
Institutional address: Department of Pediatrics Northwestern University Children's Memorial Hospital Chicago Illinois USA.
(REFERENCE 47 OF 63) 95204828
Fenrich AL Jr Perry JC Friedman RA Flecainide and amiodarone: combined therapy for refractory tachyarrhythmias in infancy.
In: J Am Coll Cardiol (1995 Apr) 25(5):1195-8
ISSN: 0735-1097
OBJECTIVES. This study assessed the safety and efficacy of combined flecainide and amiodarone therapy in controlling refractory tachyarrhythmias in infants. BACKGROUND. Single-drug as well as standard combination medical therapy for tachyarrhythmias in infants sometimes fails. In those cases, one may consider interventional therapy. However, this option may carry a high risk of morbidity and mortality in infants. The natural history of tachyarrhythmias in infants often favors eventual resolution and reinforces the importance of selecting an effective medical regimen. METHODS. We performed a retrospective analysis of nine infants (median age 2 months) who received combined flecainide and amiodarone therapy for attempted control of refractory tachyarrhythmias. Trough serum drug levels of flecainide were monitored, and 24-h ambulatory electrocardiographic monitoring was used to determine efficacy of therapy. RESULTS. Single-drug treatment with flecainide or amiodarone failed in all of the infants studied. An average of four drugs failed (range one to six) before administration of combined flecainide and amiodarone therapy. During combined therapy, the flecainide dose was 70 to 110 mg/m2 per day, and that for amiodarone was 7.5 to 13.5 mg/kg per day for a mean (+/- SD) of 9 +/- 2 days to load and 5 to 12 mg/kg per day as maintenance. Successful control of tachyarrhythmias was demonstrated in seven (78%) of nine infants (95% confidence interval 46% to 99%) (three of three with congenital junctional ectopic tachycardia, three of three with supraventricular tachycardia and one of three with ventricular tachycardia). During combined therapy, flecainide trough levels ranged from 350 to 731 ng/ml. Corrected QT intervals varied from 0.440 to 0.488 ms. No proarrhythmia occurred. None of the infants required a pacemaker, and all had normal left ventricular dimensions and fractional shortening by echocardiography. Eight of nine infants had a structurally normal heart. One infant had surgical correction of an atrioventricular septal defect. CONCLUSIONS. Combination therapy with flecainide and amiodarone appears to be safe and effective in controlling refractory tachyarrhythmias in infants. The combination of flecainide and amiodarone may obviate the need for early interventional therapy or may allow delay until the child is older.
Registry Numbers: 1951-25-3 (Amiodarone) 54143-55-4 (Flecainide)
Institutional address: Section of Pediatric Cardiology Texas Children's Hospital Houston 77030.
(REFERENCE 48 OF 63) 95052165
Gelatt M Hamilton RM McCrindle BW Gow RM Williams WG Trusler GA Freedom RM Risk factors for atrial tachyarrhythmias after the Fontan operation.
In: J Am Coll Cardiol (1994 Dec) 24(7):1735-41
ISSN: 0735-1097
OBJECTIVES. The purpose of this study was to define the incidence and risk factors for atrial tachyarrhythmias after the Fontan operation. BACKGROUND. Atrial tachyarrhythmias cause morbidity after the Fontan operation. Causative factors may be affected by the type of systemic to pulmonary connection. METHODS. The Fontan operation was performed in 270 consecutive patients between 1982 and 1992. The mean age at operation was 7.0 +/- 4.3 years. Direct atriopulmonary connection was used in 138 patients (51%), total cavopulmonary connection in 94 (35%) and right atrial to right ventricular connection in 38 (14%). RESULTS. Atrial tachyarrhythmias were seen early postoperatively in 55 patients (20%), preoperative atrial tachyarrhythmia being the only risk factor. Follow-up was achieved for 228 early survivors (97%) at a mean interval of 4.4 years. There were 20 late deaths. Late atrial tachyarrhythmias were noted in 29% of patients who received an atriopulmonary connection, 14% of those who received a total cavopulmonary connection and 18% of those who received a right ventricular connection (p < 0.02). Significant risk factors as determined by univariate and multiple logistic regression analysis were atriopulmonary connection type (odds ratio 0.40 for total cavopulmonary relative to atriopulmonary connection [p < 0.05] and 0.37 for right ventricular relative to atriopulmonary connection [p = 0.08]), longer follow-up interval (odds ratio 1.32 for each consecutive year [p < 0.002]) and atrial tachyarrhythmia in the operative period (odds ratio 6.31 [p < 0.0001]). CONCLUSIONS. Early postoperative atrial tachyarrhythmias, length of follow-up and atriopulmonary connection are significant independent risk factors for the presence of late atrial tachyarrhythmias.
Institutional address: Department of Paediatrics Hospital for Sick Children Toronto Ontario Canada.
(REFERENCE 49 OF 63) 95015485
van Engelen AD Weijtens O Brenner JI Kleinman CS Copel JA Stoutenbeek P Meijboom EJ Management outcome and follow-up of fetal tachycardia.
In: J Am Coll Cardiol (1994 Nov 1) 24(5):1371-5
ISSN: 0735-1097
OBJECTIVES. The aim of this study was to evaluate fetal tachycardia and the efficacy of maternally administered antiarrhythmic agents and the effect of this therapy on delivery and postpartum management. BACKGROUND. Sustained fetal tachycardia is a potentially life- threatening condition in which pharmacologic therapy is reported to be effective. There is ongoing discussion about optimal management. METHODS. A group of 51 patients with M-mode echocardiographically documented fetal tachycardia was studied retrospectively. RESULTS. Thirty-three fetuses had supraventricular tachycardia; 15 had atrial flutter; 1 had two episodes of both; and 2 had ventricular tachycardia. Fetal hydrops was seen in 22 patients. Thirty-four fetuses received maternal therapy with either digoxin or flecainide as the first administered drug (additional drugs were given in 12). Drug treatment was successful in establishing acceptable rhythm control in 82% (84% without, 80% with hydrops). In the latter group the median number of drugs and number of days to conversion were higher. Three patients with fetal hydrops died. In 50% of cases, tachycardia reappeared at delivery: 9 neonates presented with atrial flutter, 14 with supraventricular tachycardia and 1 with ventricular tachycardia. Seventy-eight percent of the group had pharmacologic therapy by 1 month of age and 14% by 3 years. CONCLUSIONS. Fetal tachycardia can be treated adequately in the majority of patients, even in the presence of hydrops, and therefore emergency delivery might not be indicated. Digoxin and flecainide were drugs of first choice and produced no serious adverse effects in this series of patients. The majority of patients do not require prolonged therapy.
Registry Numbers: 20830-75-5 (Digoxin) 54143-55-4 (Flecainide)
Institutional address: Division of Pediatric Cardiology University of Utrecht The Netherlands.
(REFERENCE 50 OF 63) 98184471
Lin JL Stephen Huang SK Lai LP Ko WC Tseng YZ Lien WP Clinical and electrophysiologic characteristics and long-term efficacy of slow-pathway catheter ablation in patients with spontaneous supraventricular tachycardia and dual atrioventricular node pathways without inducible tachycardia.
In: J Am Coll Cardiol (1998 Mar 15) 31(4):855-60
ISSN: 0735-1097
OBJECTIVES: We sought to investigate the long-term efficacy of slow- pathway catheter ablation in patients with spontaneous, documented paroxysmal supraventricular tachycardia (PSVT) and dual atrioventricular (AV) node pathways but without inducible tachycardia. BACKGROUND: The lack of reproduction of clinical PSVT by programmed electrical stimulation, which is not uncommon in AV node reentrant tachycardia (AVNRT), is a dilemma in making the decision of the therapeutic end point of radiofrequency catheter ablation. METHODS: Twenty-seven patients (group A) with documented but noninducible PSVT and with dual AV node pathways were prospectively studied. Programmed electrical stimulation could induce a single AV node echo beat in 12 patients, double echo beats in 4 patients and none in 11 patients at baseline or during isoproterenol infusion. Of the patients in group A, 16 underwent slow-pathway catheter ablation and 11 did not. The clinical and electrophysiologic characteristics of the 27 patients were compared with those of patients with dual AV node pathways and inducible AVNRT (group B, n = 55) and patients with dual AV node pathways alone without clinical PSVT (group C, n = 47). RESULTS: During 23+/-13 months of follow-up, none of the 16 patients with slow-pathway catheter ablation had recurrence of PSVT. However, 7 of the 11 patients without ablation had PSVT recurrence at 13+/-14 months of follow-up (p < 0.03 by Kaplan-Meier analysis). Compared with groups B and C, group A consisted predominantly of men who had better retrograde AV node conduction and a narrower zone for anterograde slow-pathway conduction. CONCLUSIONS: Slow-pathway catheter ablation is highly effective in eliminating spontaneous PSVT in which the tachycardia is not inducible despite the presence of dual AV node pathways.
Registry Numbers: 7683-59-2 (Isoproterenol)
Institutional address: Department of Internal Medicine National Taiwan University Hospital Taipei.
(REFERENCE 51 OF 63) 98086003
Orejarena LA Vidaillet H Jr DeStefano F Nordstrom DL Vierkant RA Smith PN Hayes JJ Paroxysmal supraventricular tachycardia in the general population.
In: J Am Coll Cardiol (1998 Jan) 31(1):150-7
ISSN: 0735-1097
OBJECTIVES: We sought to determine the epidemiology and clinical significance of paroxysmal supraventricular tachycardia (PSVT) in the general population. BACKGROUND: Current knowledge of PSVT has been derived primarily from otherwise healthy patients referred to specialized centers. METHODS: We used the resources of the Marshfield Epidemiologic Study Area, a region covering practically all medical care received by its 50,000 residents. A review of 1,763 records identified prevalent cases as of July 1, 1991 and all new cases of PSVT diagnosed from that day until June 30, 1993. A mean follow-up period of 2 years was completed in all incident patients. Patients without other cardiovascular disease were labeled as having "lone PSVT." RESULTS: The prevalence was 2.25/1,000 persons and the incidence was 35/100,000 person-years (95% confidence interval, 23 to 47/100,000). Other cardiovascular disease was present in 90% of males and 48% of females (p = 0.0495). Compared with patients with other cardiovascular disease, those with lone PSVT were younger (mean 37 vs. 69 years, p = 0.0002), had a faster PSVT heart rate (mean 186 vs. 155 beats/min, p = 0.0006) and were more likely to have their condition first documented in the emergency room (69% vs. 30%, p = 0.0377). The onset of symptoms occurred during the childbearing years in 58% of females with lone PSVT versus 9% of females with other cardiovascular disease (p = 0.0272). CONCLUSIONS: There are approximately 89,000 new cases/year and 570,000 persons with PSVT in the United States. In the general population, there are two distinct subsets of patients with PSVT: those with other cardiovascular disease and those with lone PSVT. Our data suggest etiologic heterogeneity in the pathogenesis of PSVT and the need for more population-based research on this common condition.
Institutional address: Marshfield Clinic and the Marshfield Medical Research Foundation Wisconsin 54449 USA.
(REFERENCE 52 OF 63) 96221852
Naheed ZJ Strasburger JF Deal BJ Benson DW Jr Gidding SS Fetal tachycardia: mechanisms and predictors of hydrops fetalis.
In: J Am Coll Cardiol (1996 Jun) 27(7):1736-40
ISSN: 0735-1097
OBJECTIVES: This study had three objectives: 1) to determine the electrophysiologic mechanisms of fetal supraventricular tachycardia at presentation and postnatally; 2) to identify the clinical and electrophysiologic predictors of hydrops fetalis; and 3) to describe the medium-term follow-up (1 to 7 years) of patients with fetal supraventricular tachycardia. BACKGROUND: Fetal supraventricular tachycardia causes significant fetal and neonatal morbidity and mortality. Prenatal analysis and postnatal confirmation of fetal supraventricular tachycardia mechanisms have been limited. METHODS: Supraventricular tachycardia mechanisms were evaluated by prenatal Doppler/M-mode echocardiography, immediate neonatal surface electrocardiography and postnatal transesophageal electrophysiologic procedures in 30 consecutive patients presenting with fetal supraventricular tachycardia (17 managed prenatally, 13 first managed postnatally). RESULTS: The fetal supraventricular tachycardia mechanism was 1:1 atrioventricular conduction in 22 patients and supraventricular tachycardia with atrioventricular block (atrial flutter) in 8. At the postnatal transesophageal electrophysiologic procedure, tachycardia was induced in 27 of 30 patients; atrioventricular reentrant tachycardia in 25 (93%) of 27 and intraatrial reentrant tachycardia in only 2 (7%) of 27. Hydrops was present in 12 of 30 fetuses. Sustained supraventricular tachycardia (> 12 h) and lower gestation at presentation correlated with hydrops (p < 0.02, p < 0.05), but mechanism of tachycardia and heart rate did not. Gestational age at delivery was significantly greater in those who received intrauterine management (39 +/- 1.3 vs. 37 +/- 2.9 weeks, p = 0.04) despite earlier presentation (32.6 vs. 37.1 weeks). Cesarean section deliveries were reduced in the same group (3 of 17 vs. 11 of 13, p = 0.0006). CONCLUSIONS: Atrioventricular reentrant tachycardia was the predominant mechanism of supraventricular tachycardia in the fetus. There was a high association of supraventricular tachycardia with atrioventricular block in utero and accessory atrioventricular connections. Outcome at 1 to 7 years was excellent regardless of severity of illness at clinical presentation.
Institutional address: Department of Pediatrics Children's Memorial Hospital Chicago Illinois 60614 USA.
(REFERENCE 53 OF 63) 96185833
Pappone C Stabile G De Simone A Senatore G Turco P Damiano M Iorio D Spampinato N Chiariello M Role of catheter-induced mechanical trauma in localization of target sites of radiofrequency ablation in automatic atrial tachycardia.
In: J Am Coll Cardiol (1996 Apr) 27(5):1090-7
ISSN: 0735-1097
OBJECTIVES. We compared the efficacy of two different mapping techniques in identifying the ablation site for atrial tachycardia. Moreover, we evaluated the additive positive predictive value of mechanical interruption of atrial tachycardia to reduce the number of ineffective radiofrequency applications. BACKGROUND. Radiofrequency catheter ablation has been suggested as a highly effective technique to treat drug-resistant atrial tachycardia. However, irrespective of the mapping technique utilized, success was most often achieved with a large number of radiofrequency applications. METHODS. Forty-five patients with atrial tachycardia underwent radiofrequency catheter ablation. Mapping techniques included identification of earliest atrial activation and pace-mapping concordant sequence. RESULTS. Atrial tachycardia was successfully treated in 42 (93.3%) of 45 patients with a mean of 3.9 radiofrequency pulses/patient. An interval between the onset of the intracavitary atrial deflection and the onset of the P wave during atrial tachycardia (AP interval) > or = 30 ms (p < 0.001) and pace-mapping concordant sequence (p = 0.01) were all significant predictors of outcome. An AP interval > or = 30 ms and a pace-mapping concordant sequence were highly sensitive (92.8%, 95% confidence interval [CI] 80.5% to 98.5%; 85.7%, 95% CI 71.5% to 94.6%, respectively) but less specific (47.8%, 95% CI 37.9% to 58.2%, 36.8%, 95% CI 27.6% to 47.2%, respectively) in identifying the site of ablation. By using atrial tachycardia mechanical interruption combined with the AP interval >30 ms or the pace-mapping concordant sequence, we obtained a specifically of 76.5% (95% CI 66.4% to 84.0%) and 73.5% (95% CI 63.2% to 81.4%), respectively, and a positive predictive value of 49.2% and 44.6%, respectively. CONCLUSIONS. An AP interval > or = 30 ms and a pace-mapping concordant sequence were reliable mapping features for predicting the outcome of the ablation procedure. Mechanical interruption of atrial tachycardia improved the specificity and positive predictive value of these two mapping techniques.
Institutional address: Department of Cardiology and Cardiac Surgery Medical School Federico II University Naples Italy.
(REFERENCE 54 OF 63) 94230819
Silka MJ Kron J Park JK Halperin BD McAnulty JH Atypical forms of supraventricular tachycardia due to atrioventricular node reentry in children after radiofrequency modification of slow pathway conduction.
In: J Am Coll Cardiol (1994 May) 23(6):1363-9
ISSN: 0735-1097
OBJECTIVES. This study was performed to investigate the prevalence, mechanisms and clinical significance of supraventricular tachycardias inducible in children or adolescents after radiofrequency modification of slow pathway conduction for the treatment of atrioventricular (AV) node reentrant tachycardia. BACKGROUND. Limited data have been reported with regard to the physiology of AV node reentrant tachycardia in young patients. Radiofrequency catheter ablation allows evaluation of the effects of selective modification of the different pathways involved in AV node reentrant tachycardia. METHODS. Selective modification of slow pathway conduction was performed in 18 young patients (12.9 +/- 3.4 years old) with typical (anterograde slow-retrograde fast) AV node reentrant tachycardia. Radiofrequency energy was applied across the posteromedial or midseptal tricuspid annulus, guided by slow pathway potentials and anatomic position. Programmed stimulation was performed after modification of slow pathway conduction defined as noninducibility of typical AV node reentrant tachycardia. RESULTS. Modification of slow pathway conduction was achieved in each patient, with a median of four applications of radiofrequency energy. However, atypical forms of supraventricular tachycardia were inducible in 9 of 18 young patients after slow pathway modification: AV node reentrant tachycardia with 2 to 1 AV block (seven patients); anterograde fast- retrograde slow AV node reentrant tachycardia (five patients); and sustained accelerated junctional tachycardia (two patients). In comparison, atypical forms of tachycardia were inducible in only 2 of 59 adult patients with AV node reentrant tachycardia undergoing slow pathway modification in the same laboratory (p = 0.01). Additional applications of radiofrequency energy to the posteromedial tricuspid annulus rendered AV node reentrant tachycardia with 2 to 1 block and the fast-slow form of AV node reentrant tachycardia noninducible. Junctional tachycardia terminated spontaneously in both patients. During 9.8 +/- 3 months of follow-up, slow-fast AV node reentrant tachycardia has recurred in one patient, whereas fast-slow AV node reentrant tachycardia has occurred in two patients, both with inducible fast-slow tachycardia after the initial modification of slow pathway conduction. CONCLUSIONS. Initial applications of radiofrequency energy may selectively modify the anterograde conduction of slow pathway fibers in young patients with AV node reentrant tachycardia. This may result in AV node reentrant tachycardia with 2 to 1 AV block or a reversal of the reentrant circuit (fast-slow tachycardia). Induction of these tachyarrhythmias indicates that further applications of radiofrequency energy are required for the successful modification of slow pathway conduction in young patients. The increased prevalence of inducible atypical arrhythmias among young patients suggests differences in the anatomic or electrophysiologic substrate of AV node reentrant tachycardia that may evolve as a function of age.
Institutional address: University Arrhythmia Service Oregon Health Sciences University Portland 97201-3908.
(REFERENCE 55 OF 63) 93359652
Van Hare GF Lesh MD Stanger P Radiofrequency catheter ablation of supraventricular arrhythmias in patients with congenital heart disease: results and technical considerations.
In: J Am Coll Cardiol (1993 Sep) 22(3):883-90
ISSN: 0735-1097
OBJECTIVES. The aim of this study was to report the results and techniques of radiofrequency ablation for treatment of supraventricular arrhythmias in patients with congenital structural heart disease. BACKGROUND. The management of patients with congenital and other structural heart disease may be complicated by serious arrhythmias due to Wolff-Parkinson-White syndrome or by atrial arrhythmias after cardiac surgery. Ablation techniques using radiofrequency current are revolutionizing the management of arrhythmias, but reports have included few with structural heart disease. METHODS. Fifteen patients with significant heart disease underwent radiofrequency ablation: 11 with Wolff-Parkinson-White syndrome and 4 with intraatrial reentrant tachycardia after atrial surgery. Seven had Ebstein's anomaly, complex in two, and the rest had other defects. Coexistence of structural defects introduced significant technical difficulties to radiofrequency ablation in patients with the Wolff-Parkinson-White syndrome and was accomplished by adaptation of current techniques. Ablation of intraatrial reentrant tachycardia was performed by finding early atrial activation sites with electrogram fractionation for radio-frequency application. RESULTS. Radiofrequency ablation was initially successful in 14 of 15 patients, with cure in 10 and clinical improvement in 14. Two patients subsequently underwent cardiac surgery without perioperative arrhythmias. CONCLUSIONS. Radiofrequency ablation in patients with congenital heart disease and arrhythmias in both safe and effective and may be the preferred approach to treatment in some patients. In patients who are to undergo surgical correction or palliation, preoperative radiofrequency ablation of the tachycardia substrate is effective and may be preferred to operative accessory pathway division. The ablation of intraatrial reentrant tachycardia shows promise in the management of patients who have undergone extensive atrial surgery, and it may eventually become the preferred approach, particularly when there are contraindications to the use of antiarrhythmic agents.
Institutional address: Department of Pediatrics University of California San Francisco School of Medicine 94143-0632.
(REFERENCE 56 OF 63) 93328943
Lesh MD Van Hare GF Scheinman MM Ports TA Epstein LA Comparison of the retrograde and transseptal methods for ablation of left free wall accessory pathways.
In: J Am Coll Cardiol (1993 Aug) 22(2):542-9
ISSN: 0735-1097
OBJECTIVES. The purpose of this study was to compare success rates, procedure and fluoroscopy times and complications for the transseptal and retrograde aortic approaches in a consecutive series of patients undergoing catheter ablation of left free wall accessory pathways. BACKGROUND. Radiofrequency catheter ablation of left-sided accessory pathways can be performed either by a retrograde, transaortic approach or by means of a transseptal puncture. METHODS. A total of 106 patients (mean age 33 years, range 4 to 79) underwent attempted catheter ablation of a single left-sided accessory pathway by either the retrograde or the transseptal approach, or both. In the first 65 patients, the retrograde aortic approach was the preferred initial method. In the most recent 51 patients, we first attempted the transseptal approach whenever a physician trained in the technique was available. Ultimately, 102 (96.2%) of 106 patients had successful ablation. RESULTS. Of 89 retrograde procedures, 85% resulted in elimination of accessory pathway conduction. Four retrograde procedures performed after failure of the transseptal approach were successful. Of the 13 patients with a failed retrograde procedure, 11 later underwent ablation using the transseptal approach. Twenty-six (85%) of 33 transseptal procedures were successful. All four patients with unsuccessful initial transseptal attempts were successfully treated with the retrograde method during the same session in the electrophysiology laboratory. Ten of 11 transseptal procedures after unsuccessful retrograde procedures were successful. Crossover from the retrograde to the transseptal approach was performed during a separate session in 9 of these 11. There was no difference in total procedure time (220 +/- 12.8 vs. 205 +/- 12.5 min) (mean +/- SEM) or fluoroscopy time (44.1 +/- 4.4 vs. 44.7 +/- 5.1 min) between the retrograde and transseptal methods. Ablation time was longer for the retrograde method (69.2 +/- 10.5 vs. 43.4 +/- 9.3 min) (p < 0.01). Of patients > or = 65 or < or = 16 years old, technical factors requiring crossover to the other technique or complications occurred in 7 (42%) of 17 patients undergoing the retrograde and 1 (11%) of 9 patients undergoing the transseptal approach (p < 0.01). The overall rate of complications was the same for both (6.7% for retrograde and 6.1% for transseptal). The most serious complication involved dissection of the left coronary artery with myocardial infarction during a retrograde procedure. CONCLUSIONS. The retrograde and transseptal approaches are complementary; if one method fails, the other should be attempted, yielding an overall success rate close to 100%. Because patients undergo heparinization immediately after the arterial system is entered during a retrograde procedure, failure of that approach requires crossover to the transseptal method during a separate session or reversal of heparin; if the transseptal method is tried first, crossover to the retrograde approach can be accomplished easily during the same session. To avoid complications related to access, the transseptal method should be the first used in children, the elderly and those with arterial disease or hypertrophic ventricles.
Institutional address: Department of Medicine University of California San Francisco 94143-0214.
(REFERENCE 57 OF 63) 93107531
Kalbfleisch SJ el-Atassi R Calkins H Langberg JJ Morady F Differentiation of paroxysmal narrow QRS complex tachycardias using the 12-lead electrocardiogram.
In: J Am Coll Cardiol (1993 Jan) 21(1):85-9
ISSN: 0735-1097
OBJECTIVES. The purpose of this study was to evaluate the utility of the 12-lead electrocardiogram (ECG) for differentiating paroxysmal narrow QRS complex tachycardias. BACKGROUND. Previous studies evaluating the utility of the 12-lead ECG for differentiating paroxysmal supraventricular tachycardia types have shown conflicting results on the usefulness of some ECG criteria, and some criteria that are considered to be useful have never been formally evaluated. METHODS. Two hundred forty-two ECGs demonstrating paroxysmal narrow QRS complex (< 0.11 ms) tachycardia (rate > or = 120 beats/min) were analyzed. All ECGs were analyzed by an observer who had no knowledge of the mechanism of the tachycardia. RESULTS. There were 137 atrioventricular (AV) reciprocating tachycardias, 93 AV node reentrant tachycardias and 12 atrial tachycardias. Six criteria were found to be significantly different between tachycardia types by univariate analysis. A P wave separate from the QRS complex was observed more frequently in AV reciprocating tachycardia (68%) and atrial tachycardias (75%). A pseudo r' deflection in lead V1 and a pseudo S wave in the inferior leads were more common in AV node reentrant tachycardia (58% and 14%, respectively); QRS alternans was present more often during AV reciprocating tachycardia (27%). When a P wave was present, an RP/PR interval ratio > or = 1 was more common in atrial tachycardias (89%). During sinus rhythm, manifest pre- excitation was observed more often in patients with AV reciprocating tachycardia (45%). By multivariate analysis, the presence of a P wave separate from the QRS complex, pseudo r' deflection in lead V1, QRS alternans during tachycardia and the presence of pre-excitation during sinus rhythm were independent predictors of tachycardia type. These criteria correctly identified 86% of AV node reentrant tachycardias, 81% of AV reciprocating tachycardias and incorrectly assigned the tachycardia type in 19% of cases. CONCLUSIONS. Several features on the ECG are useful for differentiating supraventricular tachycardia type. However, approximately 20% of tachycardias may be incorrectly classified on the basis of analysis of the ECG; therefore, the ECG should not serve as the sole means for determining tachycardia mechanism.
Institutional address: Department of Internal Medicine University of Michigan Medical Center Ann Arbor 48109-0022.
*****JOURNAL OF PEDIATRICS*****
(REFERENCE 58 OF 63) 95054795
DeGroff CG Silka MJ Bronchospasm after intravenous administration of adenosine in a patient with asthma.
In: J Pediatr (1994 Nov) 125(5 Pt 1):822-3
ISSN: 0022-3476
We describe a 13-year-old patient with asthma in whom severe bronchospasm developed immediately after the intravenous administration of 12 mg of adenosine. The risk of bronchospasm in patients with reactive airway disease may favor the use of alternative methods for the termination of supraventricular tachycardia.
Registry Numbers: 58-61-7 (Adenosine)
Institutional address: Clinical Care Center for Congenital Heart Disease Oregon Health Sciences University Portland 97201-3098.
(REFERENCE 59 OF 63) 96397426
Kugler JD Danford DA Management of infants, children, and adolescents with paroxysmal supraventricular tachycardia.
In: J Pediatr (1996 Sep) 129(3):324-38
ISSN: 0022-3476
Several acceptable options are available for the successful management of children either with an acute PSVT episode or with ongoing episodes. These options include the "no treatment" management approach. Although an example of an algorithm used in one center is provided for this Medical Progress article, other algorithms also are successfully practiced among pediatric cardiologists together with primary care pediatricians. Current and ongoing updated data related to the important factors of presenting symptoms, natural history, results of the treatment options, and the risk/ benefit ratios of the treatment options are essential when one is choosing the specific management approach.
Institutional address: Joint Division of Pediatric Cardiology University of Nebraska Omaha 68114 USA.
(REFERENCE 60 OF 63) 94293122
Donnerstein RL Berg RA Shehab Z Ovadia M Complex atrial tachycardias and respiratory syncytial virus infections in infants.
In: J Pediatr (1994 Jul) 125(1):23-8
ISSN: 0022-3476
Respiratory syncytial virus (RSV), a common cause of respiratory infections in children, has only rarely been associated with acquired heart disease. We reviewed hospital charts, rhythm strips, and electrocardiograms of 8 infants with abnormal supraventricular tachycardia (SVT), > 250 beats/min, associated with acute RSV infections. Cultures of nasopharyngeal specimens from six of eight infants grew RSV. Two infants with negative viral culture results had symptoms typical of an RSV infection during a documented RSV epidemic. Two infants had congenital heart defects. Seven of the eight infants had an ectopic atrial tachycardia, chaotic atrial tachycardia, or atrial flutter, and five of eight had episodes of nonsustained wide-complex SVT. One patient was initially treated with intravenously administered lidocaine for an incorrect diagnosis of ventricular tachycardia. SVT was unrelated to either beta-agonist therapy or hypoxic episodes. SVT did not recur after discharge in any infant with a structurally normal heart. Both patients with structural heart disease had recurrences of SVT. We conclude that RSV infections in infants may be associated with unusual atrial tachycardias and that the diagnosis may be complicated by episodes of nonsustained, wide-complex tachycardias. In patients with RSV and structurally normal hearts, chaotic and ectopic atrial tachycardias are self-limited and do not require prolonged drug therapy.
Institutional address: Department of Pediatrics Steele Memorial Children's Research Center Tucson AZ.
(REFERENCE 61 OF 63) 94111002
Ralston MA Knilans TK Hannon DW Daniels SR Use of adenosine for diagnosis and treatment of tachyarrhythmias in pediatric patients.
In: J Pediatr (1994 Jan) 124(1):139-43
ISSN: 0022-3476
This report reviews our experience with the use of adenosine for diagnosis and treatment of narrow QRS complex tachyarrhythmias in children. All electrocardiograms obtained since the introduction of adenosine for clinical use at one pediatric tertiary care institution during an 18-month period were reviewed, and those patients receiving adenosine were included for study. Of the 24 patients who received adenosine, the median age was 4 years; four neonates were included. Adenosine produced atrioventricular block in 21 (88%) of 24 patients. It terminated the tachyarrhythmia in 11 patients and produced atrioventricular block but did not terminate the tachyarrhythmia in 10 patients. The mechanism of the arrhythmia was known in three patients before adenosine administration. Adenosine was useful in establishing the mechanism of the tachyarrhythmia in 17 of the remaining 18 patients but was not useful in one patient, in whom the arrhythmia was successfully terminated because a good-quality electrocardiogram was not obtained during adenosine administration. Therefore the mechanism of the supraventricular tachycardia was ultimately determined for all patients in whom adenosine successfully produced atrioventricular block and had acceptable electrocardiographic tracings. Side effects were limited and transient. We conclude that adenosine was a safe and effective agent for the pharmacologic treatment of narrow QRS complex tachyarrhythmias in our patients, including those less than 1 year of age. If proper electrocardiographic recordings are performed during adenosine administration, it is also helpful in establishing the cause of the tachyarrhythmia.
Registry Numbers: 58-61-7 (Adenosine)
Institutional address: Children's Hospital Medical Center Cincinnati Ohio.
*****NEW ENGLAND JOURNAL OF MEDICINE*****
(REFERENCE 62 OF 63) 94217765
Kugler JD Danford DA Deal BJ Gillette PC Perry JC Silka MJ Van Hare GF Walsh EP Radiofrequency catheter ablation for tachyarrhythmias in children and adolescents. The Pediatric Electrophysiology Society.
In: N Engl J Med (1994 May 26) 330(21):1481-7
ISSN: 0028-4793
BACKGROUND. Although radiofrequency catheter ablation has been used extensively to treat refractory supraventricular tachycardia in adults, few data are available on its safety and efficacy in children and adolescents. We reviewed registry data obtained from 24 centers to evaluate the indications, early results, complications, and short- term follow-up data in young patients who underwent this procedure. METHODS. Standardized data were submitted for 652 patients who underwent 725 procedures between January 1, 1991, and September 1, 1992. The mean length of follow-up was 13.5 months. RESULTS. The median age of the patients was 13.5 years, and 84 percent of them had structurally normal hearts. The initial success rates for ablation of atrioventricular accessory pathways (508 of 615 procedures) and atrioventricular-node reentry (63 of 76 procedures) were both 83 percent. Greater institutional experience in performing ablation in children and location of the accessory pathway in the left free wall correlated with greater likelihood of sustained success. Conversely, a right free-wall pathway, the presence of other heart disease, and higher body weight were all