[Radiofrequency catheter ablation in the treatment of arrhythmias in children--efficacy, safety of the method, predictors of the procedural course and acute success]. / Ablacja pradem o czestotliwosci radiowej w leczeniu arytmii u dzieci-skutecznosc, bezpieczenstwo metody i czynniki warunkujace jej przebieg i sukces bezposredni.

BACKGROUND: Radiofrequency current ablation (RFCA) is a safe and efficient method of treatment in adult patients with symptomatic arrhythmias. Recently RFCA is being also used in the treatment of children with cardiac arrhythmias, however its value in this set of patients is poorly documented. Aims of our study were to assess the feasibility and safety of RFCA procedures in children with symptomatic supraventricular and ventricular arrhythmias, and to identify the parameters which influence the probability of acute success and RFCA course. METHODS: Consecutive 110 patients aged less than 18, who underwent RFCA due to the symptomatic arrhythmias at our center were included into a retrospective analysis. The patients presented mainly with the preexcitation syndrome (57%), 13.6% had ectopic ventricular arrhythmias, in 17.3% nodal reentrant tachycardia, in 8.2% intraatrial reentry tachycardia (IART), whereas in 5.4% ectopic atrial tachycardia (EAT) was diagnosed. Three patients had multiple arrhythmias. In ten subjects congenital heart defect was diagnosed in the past, which was treated surgically in 8. Analyzed parameters included: RFCA success-rate, procedure duration, fluoroscopy-time, perioperative complications and arrhythmia recurrence-rate during 6 months follow-up. RESULTS: Ablation was successful in 101 (91.8%) patients and abolished 104 out of 113 (92%) treated arrhythmias. Out of 9 patients with unsuccessful RFCA, three had congenital heart defect. Two complications occurred intra-operatively in two patients: in one patient pneumothorax was observed following jugular vein puncture, which resolved spontaneously without the need of drainage, in the second patient transient atrioventricular conduction block occurred during radiofrequency current application. Mean procedure duration in the studied population was 118.9 +/- 46 min, fluoroscopy exposure equaled 22.3 +/- 17min. In twelve patients (10.9%) arrhythmia recurred during the follow-up period. The longest procedure duration was observed in patients with EAT and IART, the longest fluoroscopy-time in subjects with IART, whereas the shortest fluoroscopy was observed in patients with the ventricular ectopic arrhythmias. Success-rates, complications, and recurrence-rates did not differ irrespectively from arrhythmia treated. The only independent predictor of unsuccessful RFCA was the presence of congenital cardiac defect (adjusted OR 0.15, p<0.05). The presence of cardiac defect, procedure performed without electroanatomic mapping system and less experienced operators were the parameters associated with longer fluoroscopic exposure. CONCLUSIONS: Radiofrequency current ablation is a safe and efficient method of treatment in children with arrhythmias. The presence of congenital heart defect was a factor influencing unfavorably the probability of successful RFCA. Procedural course was related to the experience of electrophysiology team, the use of advanced mapping systems and presence of cardiac defect.

Radiofrequency catheter ablation in children and adolescents with preexcitation syndrome.

BACKGROUND: Atrioventricular reentrant tachycardia (AVRT) is the most common tachycardia, accounting for 70% of regular narrow-QRS arrhythmias in children. Because of the potential disadvantages of a life-long drug therapy and relatively favourable results from radiofrequency catheter ablation (RFCA) therapy in adults, the indications for ablation therapy in children with preexcitation syndrome (PS) need to be considered. AIM: To assess efficacy and safety of RFCA in children and adolescents with PS. METHODS: The study population consisted of 302 consecutive, symptomatic, drug-refractory patients with PS undergoing RFCA. Two age groups were selected: 52 patients younger than 19 years (24 females, age 15.38+/-2.53 years); and 250 adults (115 females, age 38.67+/-13.1 years). In all study patients electrophysiological study and radiofrequency catheter ablation were performed. Comparative analysis between groups was performed with respect to procedure duration, fluoroscopy exposure time, location of accessory pathways (AP), success rate, recurrences and complications. RESULTS: No significant differences between the groups were noted with respect to procedure duration and exposure time. Success and recurrence rates did not differ between the two-age groups. The mean procedure time for children was 124.12+/-43.48 min (range 45-285) and for adults - 126.3+/-61.49 min (range 25-330) (NS). The mean fluoroscopy time for children was 27.95+/-16.86 min (range 4-75) and for adults - 31.27+/-25.51 min (range 1-131) (NS). The initial RF ablation procedure was successful in 48 (92.31%) children and in 233 (93.2%) adults (NS). Recurrence rate was 12.5% (6 patients) in children vs. 8.58% (20 patients) in adults (NS). In one child (1.92%) and in two adult patients (0.8%) serious complication occurred (NS). Electrophysiological study revealed significantly more frequent presence of the right free wall and right antero-septal AP in children than in adults (21.15 vs. 7.6%, and 17.31 vs. 5.2%, respectively, p <0.01). In adults more frequent left antero-lateral AP was detected: 32.4 vs. 7.69%, p <0.01. CONCLUSIONS: Radiofrequency catheter ablation is a safe and efficient procedure in paediatric patients with preexcitation syndrome. Effectiveness, safety, recurrence rate and RFCA procedural aspects, including total procedure time and fluoroscopy time, are comparable in paediatric patients with PS and in adults.

Radio-frequency ablation of arrhythmias following congenital heart surgery.

BACKGROUND: Cardiac arrhythmias as a late complication following congenital heart surgery are encountered more and more frequently in clinical practice. The use of new electrophysiological methods of visualisation and mapping improves the efficacy of radio-frequency (RF) ablation of these arrhythmias. AIM: To assess patterns of atrial arrhythmias following congenital heart surgery and to examine the efficacy of RF ablation using the electro-anatomical CARTO system. METHODS: Electrophysiological diagnostic study and RF ablation were performed in 24 consecutive patients (mean age 36+/-18 years) who had atrial arrhythmias following congenital heart surgery. The mechanism of arrhythmia (ectopic or reentrant) and strategy of RF ablation procedure were based on the results of the right atrial map performed during index arrhythmia. RESULTS: The patients were divided into five groups according to the type of congenital heart surgery. The ASD group consisted of 17 patients who had undergone in the past surgery due to atrial septal defect, four patients had a history of surgery due to ventricular septal defect (VSD group), and one patient each had undergone surgery due to corrected transposition of the great arteries (ccTGA), tetralogy of Fallot (TF) or dual-outflow right ventricle (DORV). During diagnostic electrophysiological study typical atrial flutter (AFL) was diagnosed in nine patients from the ASD group, atypical AFL in three ASD patients, and ectopic atrial tachycardia (EAT) in six ASD patients. In one patient EAT was induced after ablation of typical AFL. Of the VSD patients, three had atypical AFL, and one had typical AFL. The patient following surgery for ccTGA had atypical AFL and EAT, whereas in the two remaining patients (DORV and TF) atypical AFL was demonstrated. The efficacy of the first session of RF ablation was 83% and no complications were observed. The efficacy of RF ablation of typical AFL was 90%, atypical AFL 78%, and EAT 86% (NS). During the long-term follow-up (24+/-17 months) arrhythmia recurrences were noted in 2 (10%) out of 20 patients who were effectively treated during the first RF ablation session. CONCLUSIONS: Reentry is the most common electrophysiological mechanism of incisional tachycardias, followed by ectopic atrial tachycardia. RF ablation using the electro-anatomical CARTO system is effective and safe in this group of patients.

Iatrogenic cardiac arrhythmias following transcatheter or surgical closure of atrial septal defect in children.

BACKGROUND: Invasive procedures involving the atria may promote the development of iatrogenic cardiac arrhythmias. AIM: To analyse the prevalence of cardiac arrhythmias following transcatheter or cardiosurgical closure of the secundum type atrial septal defect (ASD). METHODS: The study group consisted of 91 patients, aged 2-18 years with haemodynamically significant ASD who underwent surgical (n=44) or transcatheter (Amplatzer occluder) (n=47) closure of ASD. Standard ECG and Holter ECG recordings, obtained before and after the procedure, were analysed. The follow-up duration ranged from 2.5 to 5.5 years. Cardiac arrhythmias were divided into benign or significant (requiring pharmacological therapy), early or late, and transient or permanent. RESULTS: Cardiac arrhythmias were detected in 16 (36%) patients who underwent surgery compared with 1 (2.1%) patient who underwent transcatheter ASD closure (p<0.05). In surgically treated patients, arrhythmias were benign in 9 patients, significant in 7 children, early in 15 subjects, late in one patient, transient in 13 children and permanent in 3 subjects. One patient, who underwent transcatheter ASD closure, developed paroxysmal supraventricular tachycardia one day after the procedure, successfully terminated with verapamil. CONCLUSIONS: Transcatheter closure of ASD is associated with a lower risk of procedure-related arrhythmias than surgical treatment. However, longer follow-up in patients treated with transcatheter procedure is needed in order to draw definite conclusions.

Comparison of heart rate variability between surgical and interventional closure of atrial septal defect in children.

This study was designed to compare reduced heart rate variability (HRV) in children with atrial septal defect (ASD) after surgical ASD closure with interventional (Amplatzer device) closure. Reduced HRV was observed in all children with ASD before treatment. HRV was further impaired 1 month after surgical ASD closure but not after catheter device closure. Three months after treatment, HRV indexes tended to normalize in both groups.

A comparison of the clinical course of preexcitation syndrome in children and adolescents and in adults.

BACKGROUND: Atrioventricular reentrant tachycardia (AVRT) in patients with preexcitation syndrome (PS) is the main cause of paroxysmal regular arrhythmias in children and adolescents. While the previously published data most commonly concern clinical consequences of PS in adults, few researchers have evaluated the problem in children and adolescents. The aim of the study was to compare the clinical course of PS between the population of children and adolescents below 19 years of age and the population of adult patients. METHOD: The study population consisted of 302 consecutive PS patients managed between January 2001 and June 2005 with radiofrequency catheter ablation (RFCA). The study population was divided into two groups: Group 1 consisting of 52 patients aged 15.38 years on average (7-18 +/- +/- 2.53) and Group 2 consisting of 250 adult patients aged 38.67 years on average (19-72 +/- 13.1). RESULTS: Patients from Groups 1 and 2 experienced their first episode of AVRT at the mean age of 13.3 years and 29.1 years, respectively (p < 0.05). The mean annual numbers of AVRT episodes in Groups 1 and 2 were 12.97 (range, 2-96; median, 8) and 8.86 (range, 2-25; median, 6), respectively (p = non-significant). Two patients from Group 1 (3.85%) and 42 patients from Group 2 (16.8%) experienced episodes of atrial fibrillation (AF) (p < 0.05). Location of the accessory pathways (AP): In Group 1, the right free wall and anteroseptal AP locations were significantly more common [11 (21.15%) and 9 (17.31%) patients, respectively, vs.q 19 (7.6%) and 13 (5.2%) patients in Group 2; p < 0.01]. In Group 2, the left anterolateral AP location was more common [81 (32.4%) vs. 4 (7.69%) in Group 1; p < 0.01]. CONCLUSIONS: In children and adolescents with PS, a significantly lower incidence of AF was found. In Group 1, RFCA was performed significantly more frequently due to the development of AVRT caused by right free wall and right anteroseptal AP, while in the group of adults, the left anterolateral AP location was found more commonly. (Cardiol J 2007; 14: 384-390).