PERMANENT PACEMAKER SELECTION AND SUBSEQUENT SURVIVAL IN ELDERLY MEDICARE PACEMAKER RECIPIENTS

Background Dual-chamber pacemakers have been in use for more than 15 y ears. Although they may confer a physiological advantage over single-c hamber Ventricular pacemakers, they are more expensive and have a gene rally shorter service life than single-chamber devices. We carried out the present study to identify patient subgroups who were preferential ly receiving greater or lesser proportions of dual-chamber devices and to determine whether the selection of different types of pacemakers w as associated with differences in mortality. Methods and Results We an alyzed a 20% random national sample of all Medicare beneficiaries aged 65 years or older who underwent initial placement of a permanent pace maker and were discharged in 1988, 1989, or 1990 (n=36312). The minimu m follow-up for vital status was 1 year. The relation of pacemaker typ e to patient and provider characteristics was determined using logisti c regression analysis. The relation between pacemaker type and mortali ty was determined using the Cox proportional hazards method. The propo rtion of dual-chamber systems that were received increased from 27.2% in 1988 to 37.0% in 1990 (P<.001). Dual-chamber pacemaker recipients w ere younger (P<.001) than ventricular pacemaker recipients. Other inde pendent correlates of dual-chamber pacemaker selection included male s ex (odds ratio and 95% confidence intervals, 1.18 and 1.12 to 1.24, re spectively), atrioventricular block (1.59 and 1.51 to 1.67), congestiv e heart failure (1.14 and 1.08 to 1.20), atrial fibrillation (0.36 and 0.34 to 0.39), and the presence of a major noncardiac diagnosis (0.86 and 0.83 to 0.89). Nonmedical predictors of dual-chamber pacemaker se lection included Medicaid eligibility (0.78 and 0.71 to 0.86), implant ation in the western United States (1.19 and 1.10 to 1.29), implantati on by a rural provider (0.70 and 0.65 to 0.76), hospitalization in a 5 00-bed-or-larger hospital (1.20 and 1.13 to 1.28), hospitalization in a private hospital (1.19 and 1.10 to 1.28), or hospitalization in a ho spital with a catheterization laboratory (1.47 and 1.38 to 1.56). Dual -chamber pacemaker selection was an independent predictor of survival at 1 year (0.82 and 0.77 to 0.87) and at 2 years (0.82 and 0.77 to 0.8 7) after controlling for potentially confounding patient-level and hos pital-level characteristics. Conclusions The present study describes i mportant variations in the clinical practice of cardiac pacing, many o f which are not based on clinical characteristics. Furthermore, the se lection of a dual-chamber pacemaker is associated with increased survi val. These results underscore the need for prospective, outcome-based clinical trials of pacemaker mode selection.