Exercise training after cardiac transplantation

During the last decade, cardiac transplantation has become the accepted form of treatment for selected patients with end-stage heart disease, which usually results from dilated cardiomyopathy or coronary artery disease. Although 5-yr survival is currently 85%, patients have complicated courses after surgery, with an ever present risk of infection and graft rejection. Because of physical inactivity and severe limitation of cardiac output preoperatively, these deconditioned patients are excellent candidates for medically supervised rehabilitative exercise training programs. Denervation of the myocardium, which occurs with cardiac transplantation, results in a loss of autonomic nervous system modulation of cardiac output, with reliance on circulating catecholamines and with a delayed heart rate and cardiac output response to the onset of exercise. Oxygen uptake kinetics are prolonged, and maximal oxygen uptake is reduced. Additional abnormalities in cardiac and pulmonary artery pressures and in ventilation during exercise have been described. The literature contains seven studies concerning the effects of exercise training in cardiac transplant recipients. Benefits resulting from training include increases in maximal oxygen uptake, peak exercise power output, anaerobic threshold, and lean body mass, reduced perceived exertion, heart rate, and blood pressure during submaximal exercise, and a lowered resting heart rate and blood pressure. There are no data to suggest that exercise training alters the incidence of infection or rejection or improves longevity or return to pre-illness lifestyle.