Abstract 12241: Electroanatomic Substrate in Postoperative Patients with Congenital Heart Disease and Intra-Atrial Reentrant Tachycardia - Increased Scar Burden after Fontan Surgery Predicts Arrhythmia Recurrence following Catheter Ablation
Introduction: There is an increased propensity to intra-atrial reentrant tachycardia (IART) recurrence after radiofrequency catheter ablation (RFCA) in Fontan patients when compared to other postoperative patients with congenital heart disease (CHD). Our aim was to compare the atrial electroanatomic substrate between postoperative CHD patients with and without Fontan surgery.
Methods and Results: Detailed electroanatomic mapping of the right atrium (RA) was performed in 41 consecutive CHD patients (age, 36±10 years; 44% male), including 11 Fontan patients (atriopulmonary connection, n=7, atrioventricular connection, n=4), who underwent their first RFCA for IART. Fontan patients had larger RA (226±85 vs. 156±58 mL, P=0.004); larger total low-voltage zone area ≤0.5 mV (44% of surface area vs. 30%, P=0.01); larger intermediate low-voltage zone area 0.1-0.5 mV (24% vs. 19%, P=0.01); larger scar area ≤0.1 mV (15% vs. 8%, P=0.03) (Figure); and more fractionated potentials (6.9% of total points vs. 2.2%, P<0.001). Successful RFCA was accomplished in 30 (73%) patients. During a follow-up duration of 2.3±1.6 years, IART recurrence occurred in 16 (47%) of 34 patients with ≥2 months of follow-up. After controlling for age, gender, and RFCA success, several electroanatomic variables predicted IART recurrence, including RA volume, intermediate low-voltage area, and scar area.
Conclusion: Compared with other CHD patients, Fontan patients demonstrated more extensive atrial remodeling characterized by larger RA volume, larger scar/low-voltage areas, and more fractionated potentials. RA dilatation and larger scar/low-voltage areas were associated with IART recurrence after RFCA. These substrate characteristics may explain the higher IART recurrence rate in patients with older-style Fontan operations.
- © 2010 by American Heart Association, Inc.