Adverse outcomes in patients with atrial fibrillation and a pacemaker: a cohort study

Abstract Background Patients with atrial fibrillation (AF) have a higher rate of pacemaker (PM) implantations compared to the general population. Little is known if a present PM in AF patients is associated with adverse cardiovascular outcomes. We therefore investigated the incidence of adverse outcomes in AF patients with PM compared to AF patients without a PM, and if the presence of a PM is independently associated with these outcomes. Methods Data from two Swiss prospective, multicenter cohort studies (Swiss-AF, Beat-AF) were analyzed. Yearly follow-ups (FU) were done in both cohorts with standardized assessment of PM status, cardiovascular risk factors, medication, and outcome events. The first main outcome was major adverse cardiovascular events (MACE), a composite of stroke or transient ischemic attack, myocardial infarction, cardiovascular death, and systemic embolism. The second main outcome was hospitalization for heart failure (HF). Secondary outcomes included the individual components of MACE. We performed time-updated, multi-adjusted Cox-regression analyses to assess the associations of PM status with the investigated outcomes. Results In 3,675 patients, the median age was 71.4 years, 28.8% were female and 445 (12.1%) patients had a PM at baseline. Over a median FU time of 7 years, 238 (6.5%) patients additionally received a PM. AF patients with PM had higher unadjusted incidence rates for MACE (5.97 vs 3.37 per 100 patient-years) and HF (5.08 vs 2.61 per 100 patient-years), compared to patients without a PM. All secondary outcomes were more frequent in AF patients with PM. In multi-adjusted regression analyses, we did not find conclusive associations of a present PM with MACE (adjusted hazard ratio (aHR) [95% CI] 1.14 [0.96; 1.35, p=0.125]) or with HF (aHR [95% CI] 1.15 [0.95; 1.39, p=0.145]). A present PM was not associated with any of the secondary outcomes, except with cardiovascular death (aHR [95% CI] 1.24 [1.01; 1.52, p=0.038]) (Figure). Conclusion Patients with AF and a PM experienced substantially higher event rates for MACE and hospitalization for HF compared to AF patients without a PM. The presence of a PM itself, however, was not associated with adverse outcomes, although a slight risk increase cannot be ruled out.