Arrhythmogenic difference between the left and right atria in a canine ventricular pacing-induced heart failure model of atrial fibrillation

Background: The detail of biatrial activation during sustained atrial fibrillation (AF) has not been investigated until now. Methods: Five dogs with right ventricular pacing-induced congestive heart failure (CHF) and five normal dogs were included. Biatrial endocardiac mapping was performed using noncontact mapping system. Results: Noncontact mapping of the right atrium (RA) showed CHF dogs had a higher frequency of focal discharge from Bachmann's bundle, sinoatrial region, and crista terminalis. CHF dogs also had a higher frequency of wave break, wave fusion, and reentry. CHF dogs had greater effective refractory period (ERP) dispersion. Noncontact mapping of the left atrium (LA) showed CHF dogs had more frequent focal discharge from left superior pulmonary vein (PV), right superior PV, and left atrial appendage. CHF dogs had a higher frequency of wave break, wave fusion, and reentry. CHF dogs had greater ERP dispersion. Comparison between RA and LA showed LA had a higher frequency of focal discharge, wave break, wave fusion, and leading circle reentry than the RA. LA also had greater ERP dispersion than RA. Conclusion: CHF dogs had a higher frequency of focal discharge and reentry, suggesting that CHF provided an arrhythmogenic substrate. LA had a higher frequency of focal discharge and reentry, suggesting that LA is more important to maintain AF.