Abstract 20994: Sedentary Behavior Independently Predicts Mortality in the Pacemaker Population

Abstract

Introduction: Embedded accelerometers offer a novel method of measuring physical activity levels in the pacemaker population. In an initial cohort of 96 subjects with pacemakers, we previously showed sedentary behavior significantly correlates with decreased survival. We hypothesize that physical activity of < 2 hours/day correlates with mortality independently of the traditional cardiovascular risk factors in an expanded cohort. Methods: Records of 273 individuals with de novo Medtronic pacemaker implantation at a single center between January 1, 2005 and December 31, 2012 were reviewed. An accelerometer embedded in these devices measures activity level as above or below a 70 steps/minute threshold and reports the average hours/day of activity exceeding this threshold. Activity levels abstracted from pacemaker interrogations were averaged over a 1 year period following a 6-month blanking period after implantation. Among this cohort, 48.7% were categorized as having failed to reach the activity threshold for ≥2 hours/day (n=140). Survival was compared between groups by Kaplan-Meier estimate and Cox proportional hazards models. Multivariable logistic regression examined predictors of survival. Results: The average age of the study cohort was 71±13 years with CAD prevalent in 34.1% of subjects. Average follow-up time was 3.67±2.43 years. Death occurred in 40 subjects (14.7%). In unadjusted analysis, death was nearly 5 times more likely in the inactive group than the active group [OR 4.81, 95% CI (2.13-10.88), P<0.001]. A multivariate model revealed that < 2 hours of daily activity remained an independent predictor of death [OR 4.39, 95% CI (1.90-10.12), P=0.001] along with age [OR 1.04, 95% CI (1.01-1.08), P=0.02] while sex [OR 0.09, P=0.74] and CAD [OR 0.54, P=0.08] were not predictors. Conclusion: Sedentary behavior as measured by an implanted pacemaker correlates with increased mortality independently of traditional cardiovascular risk factors.