Electrophysiological features and catheter ablation of supraventricular tachyarrhythmias in patients with Fontan circulation: nationwide multicenter study

Introduction Electrophysiological features of supraventricular tachyarrhythmia (SVT), efficacy and safety of catheter ablation in patients with Fontan circulation are not well known. This study aimed to elucidate the electrophysiological features of SVT, efficacy and safety of catheter ablation in patients who underwent Fontan procedure. Methods A total of 39 patients (age, 27.9 ± 9.8 years, 21 men) with Fontan circulation who had undergone catheter ablation for SVT were retrospectively included. SVT includes atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), atrioventricular reciprocating tachycardia involving twin atrioventricular nodes (AVRT-TN), focal atrial tachycardia (AT), intraatrial reentrant tachycardia (IART), and atrial fibrillation (AF). The characteristics of underlying congenital heart disease, Fontan type, how to puncture the Fontan conduit, tachycardia mechanisms, acute success rate, complications, and recurrence rate of catheter ablation were analyzed. Results Forty-nine SVTs were induced and 58 procedures were performed. Congenital heart diseases of the patients were as follows: atrioventricular septal defect (AVSD) + double outlet right ventricle (DORV) (20.5%), tricuspid atresia (TA) (15.4%), AVSD (10.3%), AVSD + pulmonary atresia (PA) (7.7%), DORV (7.7%), DORV + double inlet right ventricle (DIRV) (5.1%), DORV + mitral atresia (MA) (5.1%), DORV + transposition of the great arteries (TGA) (5.1%), PA (5.1%), et al. Fontan types were as follows: APC (17.9%), lateral tunnel (38.5%), and extracardiac conduit (43.6%). Inducible tachycardias were intraatrial reentrant tachycardia (36.7%), focal atrial tachycardia (24.5%), atrioventricular (AV) nodal reentrant tachycardia (12.2%), AV reciprocating tachycardia involving twin atrioventricular nodes (12.2%), AV reentrant tachycardia (8.2%), and atrial fibrillation (6.1%). Acute success and complication rates per procedure and recurrence rate per patient were 75.9%, 5.2%, and 28.2% respectively. Conclusions IART and focal AT are the most common tachycardia in patients with Fontan circulation. Catheter ablation for SVT after Fontan conduit puncture is effective and safe in patients with lateral tunnel or extracardiac conduit Fontan.