Cardiac Rehabilitation and Risk of Incident Atrial Fibrillation in Patients With Coronary Artery Disease.

Abstract

Patients with coronary artery disease (CAD) are at risk for developing atrial fibrillation (AF). Whether attending a cardiac rehabilitation (CR) program can attenuate this risk is unclear. This retrospective cohort study included patients who were free of pre-existing AF and referred to CR after coronary revascularization between April 2004 and March 2015 in Calgary, Canada. Patients with incident AF were identified using administrative data and the local electrocardiogram repository. Exposure variables and covariates were extracted from electronic medical records of a CR program and a clinical registry. The study included 11,662 patients (mean age [standard deviation], 60.9 [10.9] years; male, 80.6%). In a median follow-up of 4.8 years, the cumulative incidence rate of AF was 1.04 per 100 person-years. There was no association between completion of CR and the risk of incident AF after adjusting for baseline characteristics (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.83-1.15). However, each higher metabolic equivalent (MET) of baseline cardiorespiratory fitness (CRF) and each MET gain in CRF following CR were independently associated with a 12% (95% CI, 6%-18%) and 18% (95% CI, 6%-28%) lower relative risk of incident AF, respectively. The risk of incident AF declined progressively, with the baseline CRF increasing up to 9.0 peak METs and with the 12-week CRF increasing up to 10.3 peak METs; beyond these peak MET levels, benefits plateaued. Completion of CR alone was not associated with a lower risk of incident AF. However, higher baseline CRF and greater CRF improvement had dose-dependent protective effects.