Longitudinal study of heart disease in a Jamaican rural population. I. Prevalence, with special reference to ECG findings.

A long-term epidemiological study of heart disease in a representative rural community in Jamaica was started in 1962-63 and the first follow-up survey was carried out in 1967-68. This report describes the prevalence of several cardiovascular characteristics at each survey, and their associations with other measurements. The nature of the electrocardiographic abnormalities and their relationship with symptoms of effort pain and prolonged chest pain suggests that much of the disease seen in this population is ultimately ischaemic in origin despite evidence that classical myocardial infarction and severe coronary atheroma are relatively infrequent. Nevertheless both the symptoms and the electrocardiographic abnormalities had features that were not completely typical of occlusive disease of extramural coronary arteries. These findings are discussed in terms of the four conditions-hypertension, conventional coronary heart disease, small artery disease, and cardiomyopathy-that are believed to account for most cases of heart disease in this community, and it is concluded that the overall pattern of disease cannot be explained by any single disorder of overriding importance. The evidence suggests that all may be important contributors.