Introduction: Patients with coronary artery disease (CAD) and chronic heart failure (HF) exhibit impaired musculoskeletal function and exercise capacity, as well as a reduced quality of life, leading to increased morbidity and mortality. In HF, metabolic impairment and a decline in mitochondrial function affect both the heart and peripheral muscles, contributing to exercise intolerance. This study investigated the effects of cardiac rehabilitation (CR) on improvements in physical function, as well as muscle strength in CAD patients with HF (CAD+HF) and without HF (CAD).
Methods: A total of 118 CAD+HF (21% female; 56.3±7.2 years; BMI 29.9±5.3 kg/m2) and 370 CAD patients (23% female; 55.5±7.1 years; BMI 30.1±4.8 kg/m2) participated in a structured 3–4-week CR program after myocardial infarction and/or percutaneous transluminal coronary angioplasty and/or coronary artery bypass graft. In CAD+HF patients, 59% presented with slightly reduced left ventricular ejection fraction (41-50%), 36% with moderately reduced LVEF (31-40%) and 5% (<30%) with severely reduced LVEF. Physical function and muscle strength were assessed at admission and discharge using a test battery including isometric strength tests of the legs, trunk, arms and hands, as well as the 30-second chair rise test and the 6-minute walking test (6MWT). Body composition was assessed using bioelectrical impedance analysis. Guideline-based CR consisted of physical training, including individualized resistance training three times per week, daily cycle ergometer training adjusted to baseline ergometer workload, walking, aqua fitness (only for LVEF >30%), outdoor activities and relaxation techniques.
Results: CAD+HF and CAD patients were referred to CR with functional capacity in terms of chair rise test (CAD+HF, 12.8±3.4 repetitions; CAD, 13.1±3.5 repetitions; p=0.316) and 6-MWT performance (CAD+HF, 516.9±80.1 m; CAD, 541.7±92.8 m; p=0.013). During rehabilitation, CAD+HF and CAD patients showed comparable improvements in functional performance, demonstrated by the chair rise test (CAD+HF, +2.7±2.6 repetitions; CAD, +3.2±2.7 repetitions; p=0.102) and 6MWT (CAD+HF, +57.5±56.2 m; CAD, +51.3±49.5 m; p=0.308). In addition, CR led to significant improvements in muscular strength of the legs, arms and trunk (all p≤0.01), resulting in a combined strength increase of 243.8±442.0 N in CAD+HF patients and 265.1±359.2 N in CAD patients, with no significant difference between both groups (p=0.663). Of note, handgrip strength increased significantly in CAD patients only (p<0.001). Both groups exhibited comparable changes in body composition (all p≥0.260).
Conclusion: Patients suffering from CAD and HF demonstrated significant and clinically relevant improvements in physical performance and muscular strength during CR, with comparable benefits to CAD patients without HF. These changes were independent of age, sex and impairment of LVEF and suggest that guideline-based CR may effectively improve the metabolic impairment in CAD+HF patients.
