Long-term outcome of atrial synchronous mode pacing in patients with atrioventricular block using a single lead

Background: Current guidelines suggest the use of atrial synchronous mode (VDD) pacemakers in patients with atrioventricular (AV) block and normal sinus node function. However VDD mode is being used much less than expected. The objectives of our study were to evaluate the efficacy of VDD pacing in long-term follow-up and to find risk factors for VDD loss. Methods: We retrospectively evaluated all patients with VDD pacemakers who were implanted in our center between 1995 and 2007. Results: During the study period, 123 consecutive patients with AV block (51% men, age 62 ± 17.8 years) received a VDD pacemaker. Mean follow up duration was 4.5 ± 3.2 years. At the last follow up visit, 21 patients (21.6%) lost their original VDD mode and were programmed to ventricular-based pacing (VVIR) (undersensing, 11; chronic AF, 7; SND, 3). In 28 patients,VDD mode was restored or maintained by increasing atrial sensitivity. No episodes of atrial oversensing were observed. In multivariate analysis history of paroxysmal AF (p = 0.007, odds ratio 36.6, 95% confidence interval 2.7-493.7) and p wave lower than 1 mv during the follow up (p = 0.021, odds ratio 7, 95% confidence interval 1.3-36.7), were found risk factors to VDD loss. Conclusions: VDD pacing has good long-term performance. Absence of paroxysmal AF history predicts maintenance of VDD pacing mode. Taking into account that no atrial oversensing was observed, our recommendation is to increase atrial sensitivity when P wave amplitude declines to less than 1 mv.