Biatrial Epicardial Pacing Prevents Atrial Fibrillation and Confers Hemodynamic Benefits After Coronary Artery Bypass Surgery

Abstract

Biatrial pacing (BIP) can be more effective than standard right atrial pacing (RAP) in preventing atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG). However, the mechanisms and hemodynamic benefits of BIP have not been studied in detail. This study examined the efficacy and hemodynamic benefits conferred by overdrive epicardial BIP in preventing post-CABG AF. After undergoing CABG, 72 patients (mean age = 66 +/- 12 years, 48 men) were randomly assigned to triggered BIP (BIP-AAT; n = 50) versus single RAP (RAP-AAI; n = 22). The hemodynamic effects of BIP were measured by right heart catheterization and echocardiography. The patients were monitored for 8.8 +/- 2.4 days after CABG to detect episodes of AF. The incidence of AF was significantly lower in the BIP-AAT group (22.0%) than in the RAP-AAI group (59.1%, P < 0.01). Cardiac output was significantly higher and pulmonary artery wedge pressure (PAWP) significantly lower during BIP-AAT than during RAP-AAI. The E-wave (65.2 +/- 37.8 vs 57.8 +/- 37.8 cm/s, P < 0.05) was significantly higher during BIP-AAT, and the interval between atrial pacing spike and the end of A-wave (241 +/- 18.4 vs 286 +/- 17.2 ms, P < 0.001) was significantly shorter during BIP-AAT than during RAP-AAI. Triggered BIP was well tolerated and significantly reduced the incidence of post-CABG AF compared to single-site RAP. The hemodynamic improvements conferred by BIP-AAT were due to a shortening of the inter-atrial conduction delay and greater contribution of left atrial contraction. These hemodynamic benefits may play a role in lowering intra-atrial pressure and in preventing AF.