Abstract 3371: Recurrence of Atrial fibrillation Following RF Ablation Correlates with the Extent of Post-procedural Left Atrial Scarring on Delayed-Enhancement CMR
The reasons for success or failure of radiofrequency (RF) ablation therapy in atrial fibrillation (AF) patients remain to be defined. Cardiovascular magnetic resonance (CMR) can visualize RF ablation scar in the left atrium (LA). We sought to examine the relationship between RF ablation delayed-enhancement CMR and clinical success in this population.
Methods: 32 patients with AF who had interpretable CMR images of left atrial (LA) scar after pulmonary vein (PV) isolation and documented follow-up to monitor recurrence of AF, were enrolled. Mean follow-up was 4.9 months. The volume of scar in posterior LA wall and PV ostia (right inferior and superior (RIPV, RSPV) and left inferior and superior PV (LIPV, LSPV)) was measured in a blinded fashion, by identification of hyperenhancement (Fig. A⇓). The volume of scarring for patients with and without recurrence was compared using student’s t-tests. Kaplan-Meier curves were generated using median scar volumes as cutoffs and compared using log-rank tests.
Results: Patients without recurrence of symptomatic or asymptomatic AF (63%) had significantly greater volume of scar in the posterior LA wall (2.8±1.3 vs. 1.9 ±0.8mls, p=0.028), and in the right inferior PV (2.4±1.1 vs. 1.6 ±1.1 mls, p=0.046). In other regions the differences were not significant (2.4±1.0 vs. 2.7 ±1.2 mls for LIPV; 1.3 ±1.2 vs. 0.8±0.5 mls for LSPV, 1.8 ±1.2 vs. 1.3±1.2mls for the RSPV). Kaplan Meier analysis (Fig B⇓) demonstrated improved freedom from AF recurrence in patients with greater RIPV scar (p=0.003).
Conclusion: CMR measures of RF ablation scar volume in the RIPV and posterior LA wall correlate with RF ablation clinical success and may be useful to guide management.