Excess fatigue is a common symptom of many chronic cardiovascular disorders with low cardiac output. Impairment of skeletal muscle function due to metabolic alterations seems to play a major role. In heart failure fatigue is a predominant symptom. It may be an early symptom on diseases with slow but progressive inhibition of blood flow, i.e. in constrictive pericarditis, pulmonary hypertension or mitral valve stenosis. Excess fatigue as a precursor of myocardial infarction is being discussed. Finally fatigue may be a limiting side effect of diuretic and beta-blocking agents.