There has been extensive interest in using pacing mode and specialized pacing algorithms to prevent atrial fibrillation (AF). There are two issues to consider with regard to pacemakers and AF prevention. First, in patients without permanent AF who require pacemakers for a bradycardia indication, maintenance of atrioventricular synchrony (ie, physiologic pacing) is associated with a reduced incidence of AF . Second, in patients with a history of AF, atrial pacing has been suggested as a means to reduce AF recurrences, particularly with novel pacing strategies (dual-site atrial pacing, overdrive atrial pacing).
The data evaluating the efficacy of pacing to prevent AF will be reviewed here. The utility of other nonpharmacologic strategies for preventing AF are discussed separately. (See "Catheter ablation to prevent recurrent atrial fibrillation" and "Surgical approaches to prevent recurrent atrial fibrillation" and "General principles of the implantable cardioverter-defibrillator", section on 'Atrial defibrillation'.)
PHYSIOLOGIC PACING IN PATIENTS REQUIRING PACING
Isolated right ventricular (RV) pacing disrupts the normal sequence of activation of the atria and ventricles in patients in normal sinus rhythm. The failure to activate the atria before the ventricles with RV pacing is termed atrioventricular (AV) dyssynchrony and may promote atrial fibrillation (AF). In addition, RV pacing causes the right ventricle to contract before the left ventricle (LV) and causes the septum to contract before the lateral wall of the LV, simulating the effects of left bundle branch block. This phenomenon is referred to as ventricular dyssynchrony or asynchrony and can also lead to AF. This risk can be reduced by maintaining AV synchrony and by minimizing the amount of ventricular pacing. (See "Modes of cardiac pacing: Nomenclature and selection", section on 'Physiologic pacing' and "Modes of cardiac pacing: Nomenclature and selection", section on 'Modes to minimize ventricular pacing'.)
The term "physiologic pacing" has historically been used to describe the maintenance of AV synchrony. However, it can also encompass maintenance of ventricular synchrony. The benefit of physiologic modes of pacing on the development of AF has been demonstrated in a number of clinical trials [2-12]. The following discussion will review the results from a meta-analysis and the three largest trials: CTOPP, MOST, and SAVE PACe.
Mechanisms — Several mechanisms may contribute to the benefit of physiologic pacing in preventing AF in patients who are treated with standard-chamber dual-chamber pacing. (See "The electrocardiogram in atrial fibrillation".)