Recent prospective clinical trials have demonstrated that physiologic pacing mode reduces the risk of atrial fibrillation (AF) compared to single chamber ventricular pacing in patients with sick sinus syndrome (SSS).^1–,³ Previous studies have shown that patients with a prior history of AF before pacemaker implant are associated with an increase risk of persistent AF.³ Recent advances in the ability to store diagnostic information in implanted devices have provided an opportunity for detection and documentation of AF. The aim of this study was to define the prevalence and clinical significance of device detected AF episodes in patients implanted with pacemakers for SSS.

METHODS

We studied the clinical characteristics and long term clinical outcome in patients with SSS who had received a dual chamber rate responsive pacemaker (DDDR) for symptomatic bradycardia in our institutions from 1992 to 1998. Patients were eligible if they received a DDDR pacemaker which was capable of providing diagnostic counters for supraventricular tachyarrhythmias and was programmed “ON”. P wave analysis was manually measured by a single investigator. A surface echocardiogram was performed in all patients before implant to assess left atrial size, left ventricular ejection fraction, and left ventricular mass.

Data were retrospectively collected regarding demographic characteristics, device diagnostics, clinical status, and outcome during the follow up period. Clinical data were retrieved from the medical records and subsequently during the most recent clinic visit. The following …