Pacing mode survival in patients with single chamber atrial pacemaker for sinus node dysfunction.

Background: Single chamber atrial pacemaker should be sufficient for patients with sinus node dysfunction (SND) with normal atrioventricular (AV) conduction. However, most patients undergo dual chamber pacemaker implantation because of concern of new onset AV block. The annual incidence of new AV block has been reported from 0.