Early detection of silent ischaemic heart disease by 24-hour electrocardiographic monitoring of active subjects.

Continuous 24-hour recordings of the electrocardiogram during everyday activities were obtained in 8o subjects with praecordial symptoms, who had normal 12-lead resting electrocardiograms and negative Master two-step tests. The ages of the subjects varied between 4I and 76 years (average 54-7). Forty-three were men and 37 were women, with similar age distribution in each of the sexes. In 37 patients ischaemic ST-T changes were observed during various phases of the day, the incidence being higher among men (55_5%), than women (37.8%). Follow-up examinations 6 to I2 months later in these 37 patients revealed that i patient had had a myocardial infarction, 7 others had developed pathological changes in the resting electrocardiogram, and in I6 patients the praecordial symptoms had become worse. In the 43 subjects in whom the 24-hour monitoring was negative, none developed ischaemic attacks, deterioration in clinical symptomatology, or changes in the resting electrocardiogram during the 6 to I2 month folloup period. We conclude that 24-hour monitoring of the electrocardiogram under normal everyday activity is a reliable and convenient method for detecting ischaemnic changes at an early stage.