Abstract: Objective: To compare epicardial electrograms between the left atrium (LA) and pulmonary veins (PVs) dynamically at development of persistent atrial fibrillation(AF) in goats PVs. Methods: Ten female goats were instrumented with electrodes at the LA and left side PV. Sustained AF (＞24 h) was induced in the goat by rapid intermittent left atrial pacing for(9.5±2.3)days at a pacing interval of 20 ms for 1 s with a maximum output of 6.0 V, followed by a 2-s period without pacing. Characteristics of PVs and LA epicardial electrograms were analyzed in the development of AF. Results: With prolonged stimulation, the duration of AF was prolonged, complex fractionated atrial electrograms(CFAEs) in LA and was increased gradually, PVs had more CFAEs than LA all the time. When induced AF lasted for more than 24 h, CFAEs in PVs became sustained approximately (2.7%±3.6% vs 92.6%±6.4%, at onset of AF vs AF lasted for more than 24 h, P＜0.05), and the ratio of CFAEs in PVs was more than that in LA (92.6%±6.4% vs 72.8%±5.3%, P＜0.05). Conclusion: The epicardial CFAEs are in specific area, which increase along with electrical remodeling. The epicardial CFAEs may play an important role in the maintenance of AF in this model.

Key words: atrial fibrillation, epicardial electrograms, pulmonary vein, left atrium, goat