Permanent ventricular and dual chamber cardiac stimulation: role of pacing mode in relation to chronic atrial fibrillation risk and stroke development.

Ventricular single chamber permanent cardiac pacing undoubtedly eliminates symptoms related to extremely low cardiac rate, but also contributes to increased morbidity due to onset of permanent atrial fibrillation (PAF). Many studies have shown the superiority of atrial and dual chamber cardiac pacing in reducing atrial fibrillation risk and in preventing correlated embolic complications. It is not known, however, if this advantage is maintained in the elderly and in particular in the oldest old people. From 1986 onwards, we analyzed 690 chronically paced patients, 472 received a single chamber ventricular pacemaker (VP), while 218 received a dual chamber pacemaker (DP). All patients underwent regular controls every 6 months. End points of the study were the onset of atrial fibrillation, embolic events and death. Life table analysis of the incidence of all the events during a follow-up of 120 months was carried out, distinguishing two groups (VP and DP) homogeneous in mean age and type of cardiopathy. The total incidence of PAF was 51.4% in the VP and 11.4% in the DP group (P<0.05). After 7 years from implant, PAF was present in 90% of VP and 20% of DP patients (P<0.001). We found a significantly higher occurrence of cerebral ischemic events (stroke or transient ischemic attacks) in the VP group (P<0.05). Even if no great difference in mortality was found between the two groups, a significant reduction of cardiovascular mortality associated with DP has been observed in the subgroup of patients with sick sinus syndrome.