Atrial septal pacing in patients with paroxysmal atrial fibrillation. Initial experience.

The aim of the study was to evaluate atrial septal (AS) pacing guided by electrophysiological study (EPS), as an alternative treatment modality in patients (pts) with lone paroxysmal atrial fibrillation (PAF). We evaluated 7 pts (5M, 2F, 58+/- 5.6 years) with drug refractory PAF. The incidence of symptomatic PAF was 1.2+/- 0.4 episodes per pt/month during the last 6 months. All pts had P wave duration (3) 100ms (118+/- 10 ms) on the surface EGG. During the EPS the AS was paced from multiple sites. We considered the site of AS where the timing between the high right atrium and distal coronary sinus electrograms was pound 10 ms, as the most suitable site in order to decrease the interatrial conduction time. A standard active fixation screw-in lead (Medtronic 4068, Medtronic 4568) was attached to the interatrial septum at this site which was superior to the coronary sinus os, close to the fossa ovalis. A DDD-R generator (Medtronic Thera DR) was implanted and programmed initially in AAT mode, 75 bpm. During a follow-up period of 6+/- 3 months, 2 pts were free of symptoms. In 5 pts the PAF recurred and the pacing mode was programmed to DDD-R and antiarrhythmics restarted. One pt remained asymptomatic, and in 2 pts the arrhythmia recurred I but the pts reported significant improvement, so no further treatment was required. The last 2 pts remained severely symptomatic and atrioventricular junctional ablation was decided. We conclude that AS pacing in pts with drug refractory PAF is a challenging new technique. The limited population of our study cannot be used for safe validation of the method. Our initial experience suggests that certain pts with PAF can be improved by this method.