[Safety and effectiveness of dual chamber pacing in patients over 80 years of age with previous episodes of paroxysmal atrial fibrillation].

Background: Dual chamber pacing (DDD) in the elderly is still a controversial issue because of its short life expectancy and the risk of atrial fibrillation. The aim of the study was 1) to evaluate the cumulative survival and the events capable of modifying it, 2) to evaluate the stability of sinus rhythm, and 3) to try to identify patients who are at a higher risk of developing permanent atrial fibrillation after DDD implantation. We evaluated clinical, electrophysiological and pacing parameters at the time of implantation.

Methods: We examined retrospectively a group of 135 consecutive patients who were > 80 years old and who were treated with DDD in the last decade.

Results: At the time of evaluation (mean 33.51 +/- 27.10 months, range 4-148 months) after DDD implantation, 72% of patients were still alive. Sinus rhythm was documented in 96 (71%) patients (group A). Thirty-nine (29%) patients (group B) developed atrial fibrillation after a mean period of 28.56 +/- 30.9 months (range 1-125 months). The right atrial endocavitary signal amplitude was lower in group B compared to that observed in group A (2.6 +/- 1.16 vs 3.27 +/- 1.91 mV). The pacing and sensing atrioventricular delay were not statistically different in both groups. The minimum heart rate was higher in patients who developed atrial fibrillation (64.53 +/- 7.7 vs 67.7 +/- 5.72 b/min respectively in group A and in group B, p = 0.02). Group B patients had a higher rate of atrial fibrillation pre-implantation episodes. The incidences of sick sinus disease and of atrioventricular nodal disease were similar in both groups.

Conclusions: In elderly patients the benefits of DDD are maintained for a long period of time before the development of atrial fibrillation. Episodes of atrial fibrillation prior to DDD, apart from sinus dysfunction alone, are predictive of the development of a permanent atrial fibrillation. Permanent atrial fibrillation does not seem to reduce life expectancy. A higher minimum heart rate does not seem to prevent atrial fibrillation. The capability of recording a right atrial signal amplitude > 3 mV seems to identify those patients with a lower risk of developing atrial fibrillation.