Maximizing patient benefit from cardiac resynchronization therapy with the addition of structured exercise training: a randomized controlled study.

Abstract

We evaluated the benefits of additional exercise training after cardiac resynchronization therapy (CRT). Cardiac resynchronization therapy results in improved morbidity and mortality in appropriate patients. We hypothesized that a structured exercise training program in addition to CRT would maximize the improvements in exercise capacity, symptoms, and quality of life (QOL). Fifty patients referred for CRT were recruited. Patients were assessed before and 3 and 6 months after CRT. Functional class and QOL scores were recorded, and exercise tests were performed with hemodynamic measurements. Peak lower limb skeletal muscle torque was measured during extension, and echocardiography was undertaken at each visit. At 3 months, patients were randomized with a simple sealed envelope method to exercise training (n = 25) or control group (n = 25). The exercise group underwent an exercise program consisting of 3 visits/week for 3 months. Paired sample t tests were used to look for in-group differences and independent sample t tests for between-group differences. Three months after CRT there were significant improvements in all functional, exercise hemodynamic, and echocardiographic measures. After randomization the exercise group showed further significant improvements in functional, exercise hemodynamic, and QOL measures compared with the control group. There were also significant in-group improvements in peak skeletal muscle function and ejection fraction that did not reach statistical significance on intergroup analysis. Exercise training leads to further improvements in exercise capacity, hemodynamic measures, and QOL in addition to the improvements seen after CRT. Therefore, exercise training allows maximal benefit to be attained after CRT.