Pacemaker programming in patients with first‐degree AV‐block: Programming pattern and possible consequences

BACKGROUND: The optimal way of pacing in patients with an indication for pacing and concomitant first‐degree atrioventricular (AV)–block is not known, and consequently, firm guidelines on this topic are lacking. This study explored the current pacemaker programming pattern in patients with first‐degree AV‐block who have a dual chamber pacemaker without cardiac resynchronization. METHODS: The study was a retrospective chart review conducted at Duke University Hospital. Patients receiving a pacemaker due to sinus node dysfunction with coexistent first‐degree AV‐block were studied. Baseline demographics and characteristics, as well as pacemaker programming parameters and follow‐up data, were collected through chart review. Preimplantation and postimplantation electrocardiograms were analyzed. RESULTS: A total of 74 patients were included (mean age, 75 ± 11 y; 53% men). The mean ± SD preimplant PR interval and QRS duration was 243 ± 46 and 110 ± 30 milliseconds, respectively. A history of atrial fibrillation was present in 49% of the patients, and 77% had a normal left ventricular ejection fraction. The majority of patients (65%) had their pacemakers programmed to atrial pacing (AAI/DDD +/−R), whereas 32% and 2.7% of the pacemakers were programmed to AV‐sequential pacing (DDD) and ventricular pacing (VVI), respectively. There were no significant differences in baseline characteristics or electrocardiogram measures between patients programmed to the 3 pacing modes. Patients with pacemakers programmed to AAI had a lower ventricular pacing percentage at follow‐up (8 vs 55, and 46% [DDD and VVI, respectively]; P < .001). CONCLUSIONS: There was no evident association between baseline characteristics and programmed pacing mode in patients with first‐degree AV‐block. The choice of pacing mode affects long‐term pacing burden, which in turn has been shown to influence outcome.