Exercise-Based Cardiac Rehabilitation Improves Exercise Capacity Regardless of the Response to Cardiac Resynchronization Therapy in Patients With Heart Failure and Reduced Ejection Fraction

BACKGROUND In patients with chronic heart failure with reduced ejection fraction (HFrEF), cardiac resynchronization therapy (CRT) improves left ventricular ejection fraction (LVEF) and exercise-based cardiac rehabilitation (ECR) enhances exercise capacity. This study examined the relationship between the 2 responses.Methods and Results:Sixty-four consecutive HFrEF patients who participated in a 3-month ECR program after CRT were investigated. Patients were categorized according to a median improvement in peak oxygen uptake (PVO2) after ECR of 7% as either good (n=32; mean percentage change in PVO2[%∆PVO2]=23.2%) or poor (n=32; mean %∆PVO2=2.5%) responders. There was no significant difference in baseline characteristics between the good and poor responders, except for PVO2(51% vs. 59%, respectively; P=0.01). The proportion of good CRT responders was similar between the good and poor responders (%∆LVEF ≥10%; 53% vs. 47%, respectively; P=NS). Overall, there was no significant correlation between %∆LVEF after CRT and %∆PVO2after ECR. Notably, among poor CRT responders (n=32), the prevalence of atrial fibrillation (0% vs. 29%; P