Effect of fat pad ablation on the spatial and temporal stability of complex fractionated atrial electrogram in acetylcholine-induced atrial fibrillation.

OBJECTIVE: The objective of this study was to investigate the effect of selective fat pad ablation on the spatial and temporal stability of the complex fractionated atrial electrogram (CFAE) in acetylcholine (ACh)-induced atrial fibrillation (AF).

METHODS AND RESULTS: ACh was applied to fat pads in 10 dogs. Effective refractory periods (ERPs) at 5 different sites, AF inducibility and AF duration were obtained before and after fat pad ablation. During the first two induced AFs, the number of sites with continuous CFAEs and the duration of continuous CFAEs at every site were measured before and after fat pad ablation. The average ERP was shortened by ACh application (138 14 vs 100 15 ms, P < 0.001) and increased after fat pad ablation (100 +/- 15 vs. 115 +/- 14 ms, P < 0.001). AF inducibility (76 +/- 9% vs. 4 +/- 6%, P < 0.001) and AF duration (56 +/- 11 vs. 187 +/- 56 s, P = 0.01) increased after ACh application compared to baseline; while fat pad ablation reduced AF inducibility (76% +/- 9% vs. 54% +/- 6%, P < 0.001) and AF duration (187 +/- 56 vs. 144% +/- 35 s, P = 0.015). The percentage of sites with continuous CFAE decreased after fat pad ablation compared with that before fat pad ablation (24% vs. 82%, P < 0.001). On average, fat pad ablation reduced the duration of continuous CFAEs (188 +/- 63 vs. 139 +/- 31 s, P < 0.001).

CONCLUSION: Selective fat pad ablation can affect the spatial and temporal stability of CFAEs in ACh-induced atrial fibrillation in dogs.