Relationship Between Reverse Remodeling and Cardiopulmonary Exercise Capacity in Heart Failure Patients Undergoing Cardiac Resynchronization Therapy

• CRT responders demonstrate higher average oxygen consumption over time than nonresponders.
• Only CRT responders show improvements in ventilatory efficiency during follow-up.
• Good patient-rated physical functioning is related to higher oxygen consumption during exercise.
• CRT nonresponders might still experience benefit from CRT in their daily lives.

BackgroundStudies on the relationship between left ventricular reverse remodeling and cardiopulmonary exercise capacity in heart failure patients undergoing cardiac resynchronization therapy (CRT) are scarce and inconclusive.Methods and ResultsEighty-four patients with a 1st-time CRT-defibrillator (mean age 65 ± 11; 73% male) underwent echocardiography and cardiopulmonary exercise testing (CPX) before implantation (baseline) and 6 months after implantation. At baseline, patients also completed a set of questionnaires measuring mental and physical health. The association between echocardiographic response (left ventricular end-systolic volume decrease ≥15%) and a comprehensive set of CPX results was examined. Echocardiographic responders (54%) demonstrated higher peak oxygen consumption and better exercise performance than nonresponders at baseline and at 6-month follow-up. Furthermore, only echocardiographic responders showed improvements in ventilatory efficiency during follow-up. Multivariable repeated measures analyses revealed that, besides reverse remodeling, New York Heart Association functional class II and good patient-reported health status before implantation were the most important correlates of higher average oxygen consumption during exercise, and that nonischemic etiology and smaller pre-implantation QRS width were associated with better ventilatory efficiency over time.ConclusionsDuring the first 6 months of CRT there was a significant positive association between reverse remodeling and cardiopulmonary exercise capacity.