EXERCISE AND HEART-TRANSPLANTATION - A REVIEW

Results of heart transplantation as therapy for end-stage cardiac diseases are encouraging not only because of acturial survival curves but also because of the recovered quality of life for the heart transplant recipient. Although heart transplantation drastically improves the physical capacity of the patients, heart recipients still have a reduced maximal aerobic capacity compared to healthy people. Altered resting and exercise haemodynamics, due to cardiac denervation, are a common finding after orthotopic heart transplantation: increases in heart rate and stroke volume at exercise are first linked with the augmented venous return and later with the increased plasmatic noradrenaline level. Maximal heart rate and stroke volume are both reduced when compared to innervated heart. Reduced cardiac output response to exercise therefore results in early anaerobic metabolism, acidosis, hyperventilation and diminished physical capacity. In spite of an altered ventilatory adaptation to exercise, characterised by hyperpnoea in most transplant patients, ventilation is not the limiting factor for exercise in heart recipients without associated obstructive pulmonary disease. Endurance training restores lean tissue, decreases submaximal minute ventilation, increases peak work output, maximal ventilation and peak heart rate. Guidelines for prescribing exercise are not yet standardised due to the limited number of studies on a sufficient cohort of heart recipients. Nevertheless, recommendations similar to those used for persons with coronary heart disease, with modifications due to the denervated heart, seem to be used. The cardiocirculatory and pulmonary capacity of heart transplant recipients allow them to undertake endurance sports activities such as walking, jogging, cycling and swimming, and these should be encouraged.