740-3 Differential Impact of Pacing Mode on Long-term Survival In Patients with Conduction System Disease

Abstract

Advantages of dual chamber (DC) pacing compared to single chamber (SC) pacing have been recognized. However, the differential impact of pacing mode on long-term survival with respect to conduction abnormalities is not well established. We analyzed survival outcome in 631 pts who received permanent pacemaker for conduction system disease from 1980 to 1985. There were 245 pts (39%) with sick sinus syndrome (SSS), 386 pts (61%) with atrial ventricular block IAVB). Mean age was 78 ± 6 years; mean follow up was 5.2 ± 3.2 years. Observed survivals according to pacing mode and types of conduction system disease are summarized below (Kaplan-Meier method). Conduction system disease Pacing Mode (n) Probability of Survival (%) Log rank P 1 yr 3 yr 5 yr SSS Dual (83) 89 73 59 0.6458 Single (162) 89 73 60 AVB Dual (123) 90 83 72 0.0005 Single (263) 85 69 53 Cox multivariate analysis identified several independent risk factors for increased mortality including age, CHF, MI, diabetes mellitus, renal failure, and cancer. 1. Based on mode of pacing, long-term survivals were not significantly different between DC and SC pacing in pts with SSS. 2. In pts with AVB, DC pacing is associated with improved survival. 3. These observations do not support the notion that SC pacing increases mortality in pts with SSS.