Evidence based cardiology: Prevention of congestive heart failure and management of asymptomatic left ventricular dysfunction

This is the second of four articles The epidemiology of heart failure has been studied largely among symptomatic individuals because identification of these patients is based on clinical criteria and does not require measuring left ventricular function.1 However, identifying people who are at high risk of heart failure could lead to the implementation of strategies that could potentially prevent heart failure and improve prognosis. This article reviews the prevalence of left ventricular dysfunction, the management of asymptomatic left ventricular dysfunction, and the prevention of heart failure. ### Summary points The data on the prevalence of asymptomatic left ventricular dysfunction are limited, even though treatment of patients with this condition may be expected to improve their outcome.2–3 In 1992 McDonagh et al measured ejection fraction in 1467 people during a survey of coronary risk factors.3 The mean ejection fraction was 47% among people defined as not having cardiovascular disease, and 34% was two standard deviations below the mean. Of the 2.9% with an ejection fraction of 30%, half had no symptoms. The frequency of both left ventricular dysfunction and symptoms was greater in older age groups, increasing sharply up to the age of 45 and less sharply thereafter (table 1). Of the 7.7% with an ejection fraction of 35%, 77% were asymptomatic. Of those with definite left ventricular dysfunction (table 1), the proportion with symptoms increased with age. The group with left ventricular dysfunction had a greater prevalence of ischaemic heart …