Epicardial ablation of rotors suppresses inducibility of acetylcholine-induced atrial fibrillation in left pulmonary vein-left atrium preparations in a beagle heart failure model.

Abstract

OBJECTIVES: The purpose of this study was to provide direct evidences that rotor ablation suppresses atrial fibrillation (AF) inducibility. BACKGROUND: Micro-re-entrant wavefronts have been suggested to serve as sources of rapid activations during AF. Whether AF inducibility is suppressed by elimination of rotors remains unknown. METHODS: We used optical mapping to study Langendorff-perfused left pulmonary vein (PV)-left atrium (LA) preparations from 13 dogs with pacing-induced heart failure. Atrial arrhythmias were induced by pacing and mapped during acetylcholine infusion (1 &#x3bc;mol/l). Rotors were identified from optical recordings. Epicardial ablation was performed targeting the rotor anchoring sites in preparations with sustained (>10 min) or incessant spontaneous AF. Non-rotor ablation was performed in 4 preparations. Repeated pacing was performed to test the AF inducibility after ablation. RESULTS: Sustained AF (n = 12) and incessant spontaneous AF (n = 1) were induced after acetylcholine infusion. Pulmonary vein focal discharge was found in 9 preparations (9.2 &#xb1; 4.2 beats/s), and rotor anchoring was found at the left superior PV-LA junction in 13 preparations (9.1 &#xb1; 4.6 beats/s) and at the ligament of Marshall-PV-LA junction in 1 preparation. Epicardial rotor ablation successfully inhibited the inducibility of sustained AF in 12 of 13 preparations (p < 0.01), including 4 with the maximal dominant frequency sites located on the PV-LA junctional rotor zones (direct elimination of mother rotors). The longest AF duration was shortened significantly by rotor ablation (Wilcoxon Z = 3.60, p = 0.002, n = 13), but not by non-rotor ablation (Wilcoxon Z = 1.00, p = 0.317, n = 4). CONCLUSIONS: Epicardial ablation of the rotor anchoring sites suppresses AF inducibility. The arrhythmogenicity at the maximal dominant frequency sites is directly/indirectly suppressed by the rotor ablation.