Background: Chronic right ventricular pacing has been reported to promote cardiac dyssynchrony. The PAVE trial prospectively compared chronic biventricular pacing to right ventricular pacing in patients undergoing ablation of the AV node for management of atrial fibrillation with rapid ventricular rates.
Methods and results: One hundred and eighty-four patients requiring AV node ablation were randomized to receive a biventricular pacing system (n = 103) or a right ventricular pacing system (n = 81). The study endpoints were change in the 6-minute hallway walk test, quality of life, and left ventricular ejection fraction. Patient characteristics were similar (64% male; age: 69 +/- 10 years, ejection fraction: 0.46 +/- 0.16; 83%, NYHA Class II or III). At 6 months postablation, patients treated with cardiac resynchronization had a significant improvement in 6-minute walk distance, (31%) above baseline (82.9 +/- 94.7 m), compared to patients receiving right ventricular pacing, (24%) above baseline (61.2 +/- 90.0 m) (P = 0.04). There were no significant differences in the quality-of-life parameters. At 6 months postablation, the ejection fraction in the biventricular group (0.46 +/- 0.13) was significantly greater in comparison to patients receiving right ventricular pacing (0.41 +/- 0.13, P = 0.03). Patients with an ejection fraction <or=45% or with NYHA Class II/III symptoms receiving a biventricular pacemaker appear to have a greater improvement in 6-minute walk distance compared to patients with normal systolic function or Class I symptoms.
Conclusion: For patients undergoing AV node ablation for atrial fibrillation, biventricular pacing provides a significant improvement in the 6-minute hallway walk test and ejection fraction compared to right ventricular pacing. These beneficial effects of cardiac resynchronization appear to be greater in patients with impaired systolic function or with symptomatic heart failure.