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

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.

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.

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).

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.