cause. However, these aetiologies are not necessarily mutually exclusive, as demonstrated in the Study of Men Born in 1913 [l] and the Framingham study [16, 171. Valvular diseases, cardiomyopathy, cor pul- monale, and congenital heart diseases also contribute to a small proportion of cases of heart failure. A recent large data base is the SOLVD registry data [27], which consists of data collected in 1988 and 1989 on more than 6000 patients with heart failure or left ventricular dysfunction or both. Of these, 1322 patients met the criteria for a diagnosis of heart failure. Fifty-three per cent of the men and 42% of the women with heart failure had ischaemic heart disease as the underlying cause : 15 % of the men and 22 % of the women had hypertension as the under- lying cause; and 7% of the men and 14% of the women had aortic or valvular disease as the under- lying cause. Idiopathic cardiomyopathy (included in the ‘other or unknown’ category) accounted for 18 % and 17% of the underlying diagnoses in men and women, respectively. Because of the various underlying causes of heart failure, the number of risk factors is potentially large but similar to those for coronary artery disease and hypertension. Results from the Framingham study [8] and the Study of Men Born in 1913 [6] indicate that primary risk factors for heart failure include high blood pressure, smoking, obesity (especially abdominally distributed), excess alcohol consump- tion, psychological stress, and metabolic disturbances such as diabetes mellitus. Some risk factors may be early predictors of left ventricular dysfunction (some asymptomatic). Left ventricular hypertrophy on the electrocardiogram with or without roentgenographic evidence of car- diac enlargement, was a grave prognostic sign of impending heart failure in the Framingham study, and the combined findings further increased the risk [16]. Other predictors of an early dysfunction are high resting heart rate, low heart-rate variability, low vital capacity, and low peak expiratory flow.
Diagnosis of heart failure In medical practice, the diagnosis has to be based on patient history, clinical findings, and a limited number of investigations. The medical history is most important in assessing a patient’s risk for heart failure. A history of longstanding hypertension, angina pectoris, previous myocardial infarction, or