Electrophysiological Features and Catheter Ablation for Supraventricular Tachyarrhythmias in Patients with Fontan Circulation: A Multicenter Study

Background: Patients with Fontan circulation experience significant morbidity from supraventricular tachyarrhythmias (SVTs). However, the electrophysiological features of SVT and the efficacy and safety of catheter ablation in patients with Fontan circulation are poorly understood. This study aimed to elucidate the electrophysiological features of SVT and evaluate the efficacy and safety of catheter ablation in patients with Fontan circulation. Methods: Forty-nine patients (age, 29.2{+/-}10.0 years; 27 males) with functional single ventricle and Fontan circulation who had undergone electrophysiological study for SVT were retrospectively enrolled. Parameters analyzed included underlying congenital heart disease, Fontan type, conduit puncture technique, tachycardia mechanisms, tachycardia origin site, acute success rate, procedure-related complications, and recurrence. Results: Fifty-nine SVTs were induced, and 69 catheter ablations were performed. The Fontan types included atriopulmonary connection (APC, 18.4%), lateral tunnel (LT, 38.8%), and extracardiac conduit (ECC, 42.9%). Inducible tachycardias included intra-atrial reentrant tachycardia (IART, 39.0%), focal atrial tachycardia (AT, 28.8%), atrioventricular reentrant tachycardia (11.9%), atrioventricular nodal reentrant tachycardia (10.2%), and atrioventricular reciprocating tachycardia involving the twin atrioventricular nodes (10.2%). The right atrial (RA) lateral wall was the most common location of IART and focal AT. The acute success and complication rates were 73.5% and 4.1%, respectively. Recurrence rate was 34.7% during follow-up of 78.0{+/-}71.9 months. The cumulative recurrence rate was significantly lower in patients who underwent LT or ECC Fontan procedures than in those who underwent the APC Fontan procedure (P<0.001). Conclusions: Catheter ablation for SVT is effective and safe in patients who have undergone LT and ECC Fontan procedures.