Epidemiologic aspects of heart failure. The prevalence of heart failure in Northwest London is 0.4%, a lower figure than that quoted for the United States. Heart failure is a common reason (5%) for medical admission to the hospital in the London area. The problem of heart failure is predominantly in persons over 65 years. Coronary artery disease is the most frequent cause, and hypertension is relatively uncommon. In those patients admitted to the hospital, the prognosis is poor. 