Indication for device therapy in heart failure patients after a comprehensive cardiac rehabilitation program

Abstract

Background: Exercise based comprehensive Cardiac Rehabilitation (CR) has been shown to improve New York Heart Association (NYHA) functional class and Left Ventricular Ejection Fraction (LVEF) in Heart Failure (HF) patients. Implantable Cardioverter Defibrillators (ICD) and Cardiac Resynchronization Therapy Defibrillators (CRT-D) reduce mortality in selected patients with persistent symptoms and reduced LVEF. We sought to determine the proportion of patients with a remaining indication for device therapy after a 3 month CR program. Methods: We performed a retrospective, longitudinal study in HF patients with a LVEF ≤35% in NYHA functional class I to III, who successfully completed a 3 months CR program. The exercise training consisted of 36 sessions, including endurance and strength training. Medication was optimized during the program. LVEF, peak oxygen uptake (VO2), and Brain Natriuretic Peptide (BNP) were determined at baseline and after the program. Indications for device therapy were based on the European Society of Cardiology guidelines for management of HF (2012) and sudden cardiac death (2006). Results: A total of 300 patients were included in the analysis (mean age 59±11 years, 13.3% female). 50.7% had ischemic, 38.7% had idiopathic dilated cardiomyopathy, and 10.6% had other cardiomyopathies. At baseline, median (IQR) VO2 peak was 16.6 (5.1) ml/min/kg, LV ejection fraction was 25 (10)%, and BNP was 269 (377) pg/ml. After three months, all parameters improved significantly: peak VO2 to 17.9 (7.3) ml/min/kg, p<0.001; LFEF to 35 (15)%, p<0.001; and BNP to 180 (287) pg/ml, P<0.001. Beta-blockers and ACE-Inhibitor/angiotensin receptor blockers were used in 87.1% and 92.3%, respectively. 194 (64.7%) of patients remained with an LVEF≤35%. Of those patients, 116 (59.7%) were in NYHA functional class II and III. Dyssynchrony was present in 60 (30.9%) patients, 50 (25.8%) showed a left bundle branch block. 16 (8.2%) patients had atrial fibrillation. ICD and CRT-D devices were present in 39 (20.1%) and 9 (4.6%) patients, respectively. A formal class I or IIa indication for ICD implantation remained for 54 (27.8%) and 24 (12.4%) patients, respectively. For CRT-D implantation, class I and IIa indications were present in 26 (13.4%) and 9 (4.6%) patients, respectively. Conclusion: Despite beneficial effects of a comprehensive CR program on performance and LVEF, a persistent indication for device therapy remained in a substantial number of HF patients. To further improve prognosis and exercise capacity in these patients, follow-up should be performed in close cooperation with an electrophysiologist.