Single-Chamber versus Dual-Chamber Pacing for High-Grade Atrioventricular Block

Patients with high-grade atrioventricular block usually require the implantation of a permanent pacemaker. Retrospective studies have suggested that dual-chamber pacemakers reduce the risk of atrial fibrillation, stroke, heart failure, and death in this setting, as compared with single-chamber ventricular pacemakers. In a randomized trial comparing these two pacing methods, however, no significant advantage of dual-chamber pacing was demonstrated. In a randomized trial comparing these two pacing methods, no significant advantage of dual-chamber pacing was demonstrated. Cardiac pacing is the established treatment for high-grade atrioventricular block, but the appropriate pacing mode remains the subject of debate. 1 Single-chamber ventricular pacing prevents bradycardia and death from ventricular standstill, but dual-chamber pacing better emulates normal cardiac physiology by restoring atrioventricular synchrony and matching the ventricular pacing rate to the sinus rate. As a result, dual-chamber pacing, as compared with single-chamber ventricular pacing, improves hemodynamic function, 2 – 4 but the clinical benefit is uncertain. Nonrandomized studies suggest that dual-chamber pacing is associated with a lower incidence of atrial fibrillation, stroke, and heart failure than is single-chamber pacing. 5 There is also evidence . . .