Comparison of complex fractionated atrial electrograms between the left atrium and pulmonary veins in development of persistent atrial fibrillation in goats

Background: The role of complex fractionated atrial electrograms (CFAEs) in the maintenance of atrial fibrillation (AF) is controversial. The main problem is the underlying mechanism of CFAEs is not clear. Objective: This study aimed to compare CFAEs between the left atrium (LA) and pulmonary veins (PVs) dynamically at development of and terminations tage of persistent AF in goats and try to explore the mechanism of CFAEs. Methods: Eight female goats were instrumented with electrodes at the LA and left side PV. Sustained AF (>24 h) was induced in the goat by rapid intermintant left atrial pacing for 9.3 +/- 4.6 days. After AF lasted for more than 24 h spontaneously, propafenone was infused intravenously untiltermination of AF. Characteristics of PV sand LA electrograms were analyzed in the development and termination of AF. Results: With prolonged stimulation, the duration of AF prolonged, CFAEs in LA and PVs increased gradually, PVs have more CFAEs than LA all the time. When induced AF lasted for more than 24 h, CFAEs in PVs became sustained approximately (3.3% +/- 4.0% vs. 91.8% +/- 6.7%, 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 (91.8% +/- 6.7% vs. 78.7% +/- 4.6%, P<0.05). Administration of propafenone resulted in a gradual decrease of CFAEs in the LA and PVs (P< 0.05). CFAEs disappeared in the LA before cardioversion. Sinus rhythm resumed only when CFAEs in the left superior PV vanished completely. Conclusion: CFAEs are area-specific. CFAEs are increased gradually with the electrical remodeling. CFAEs in PVs may play an important role in the maintenance of AF in this model.