[Alternative pacing sites for the prevention of atrial fibrillation]

Background The induction of atrial fibrillation depends upon the interaction between basic rhythm, ectopic activity, and inter-/intraatrial conduction. In pacing therapy, the atrial pacing site may influence the incidence of atrial tachyarrhythmias. This review discusses the antiarrhythmic potential of different atrial pacing sites. Results Three atrial pacing modes have been evaluated with respect to their potential to prevent atrial tachyarrhythmias: biatrial, bifocal right atrial, and dedicated unifocal right atrial pacing sites. Biatrial pacing aims at shortening the global atrial activation time in patients with interatrial conduction block. Observational studies showed a suppression of atrial tachyarrhythmias in 1/3 of patients, while a randomized study could not demonstrate a significant effect. Bifocal pacing at the high right atrium and coronary sinus os showed a higher preventive efficacy than unifocal pacing in a single center experience which was partly confirmed by a multicenter trial. Atrial septal pacing at the triangle of Koch provides antiarrhythmic effects but may be more difficult to reach and limited by oversensing of ventricular far-field signals. A randomized study found a preventive effect of pacing near Bachmann's bundle; this site seems particularly attractive for its easy access and low risk of ventricular far-field oversensing. Conclusions In patients with an indication for permanent pacing and paroxysmal or persistent atrial fibrillation, the atrial pacing site may facilitate maintenance of sinus rhythm. While reliable sensing and pacing are prerequisites, particularly high septal atrial pacing may provide an additional antiarrhythmic effect at an expenditure comparable to conventional atrial pacing sites.