Cardiac transplantation has transformed the prognosis of NYHA Class IV
severe cardiac failure. However, despite a ''new heart'', the exercis
e tolerance of transplanted patients remains poor for a long time. Car
diac denervation which decreases the chronotropic reserve, diastolic l
eft ventricular dysfunction and intrinsic muscular abnormalities relat
ed to lack of training and to treatment are the underlying causes.