[Effort electrocardiography and coronary arteriography following a 1st myocardial infarction. Critical study of the effort test].

Sixty-five patients, convalescent from a first myocardial infarction (anterior in 24 cases; inferior in 41 cases), underwent an effort electrocardiogram on a treadmill and coronary arteriography. In the anterior infarcts, coronary arteriography showed single vessel disease (anterior descending artery) in 54% of cases and double or triple vessel disease in the others. The effort test was positive in only 25% of patients with an anterior infarct. The presence of stenotic lesions of the circumflex artery and/or right coronary artery was unsuspected in 63% of patients. In the inferior infarcts, there was a significant stenosis of the anterior descending artery in 51% of the cases. The effort test was positive in 54% of patients and in 77% of those the anterior descending artery showed a significant stenosis. The appearance (or increase) of ST elevation greater than or equal to 1 mm in the leads facing the infarcted zone was an indication of more severe deterioration in left ventricular function as shown by a more marked reduction in ejection fraction and a more extensive akinetic region. The co-existence of ST elevation in the leads facing the infarcted zone and of ST depression greater than or equal to 1 mm in the reciprocal leads always indicated that another major vessel was involved, but this was only found in 25% of cases in this series.