Atrial sensing and AV synchrony in single lead VDD pacemakers: A prospective comparison to DDD devices with bipolar atrial leads

Atrial Sensing and AV Synchrony in VDD and DDD Devices. Introduction: Singl e lead VDD pacing has offered an alternative to DDD systems in patients wit h isolated AV block. Up to now, however, the relative performance of these pacemaker systems was not systematically compared. Methods and Results: Three hundred sixty patients who received either a VDD pacemaker (n = 180) or a DDD device (n = 180) with a bipolar atrial lead w ere investigated prospectively for a mean period of 30 +/- 13 months. Pacem aker function was analyzed by telemetry, Holter monitoring, and exercise EG G. Time of implantation and fluoroscopy was significantly lower with VDD de vices (44.3 +/- 5.1 min vs 74.4 +/- 13.5 min and 4.6 +/- 2.5 min vs 10.3 +/ - 5.6 min in DDD pacemakers, respectively). Intermittent atrial undersensin g occurred in 23.3% of patients with a VDD pacemaker and in 9.4% with DDD d evices (NS). The incidence of atrial tachyarrhythmias did not differ betwee n the VDD (6.7%) and the DDD group (6.1%). Sinus node dysfunction developed in 1.9% of patients, but the vast majority (85.7%) of patients were asympt omatic. There was a tendency for a higher rate of operative revisions in th e DDD group (6.1% vs 3.3% in VDD pacemakers, P = 0.15). Cumulative maintena nce of AV-synchronized pacing mode was 94.9% in patients with VDD pacemaker s and 92.1% with DDD devices (NS). Conclusion: With the benefit of a simpler implant procedure, long-term outc ome of single lead VDD pacing is equivalent to DDD pacing in patients with AV block and preoperative normal sinus node function.