Prognostic significance of the ST-segment response during exercise test shortly after acute myocardial infarction. Comparison with other exercise variables.

An exercise test was made in 317 patients in the third week after acute myocardial infarction. The following types of exercise associated ST-segment responses were registered in patients less than 70-years-old. I: no ST-deviation (33.6%), II: ST-depression (42.9%), III: ST-elevation (13.4%) and IV: inconclusive ST-response (10.1%). The 5-year mortality was significantly lower in group III than in groups II and IV. Group IV had a significantly higher 5-year mortality than all the other groups. Patients with ST-depression had an increased late mortality compared to that of the patients without ST-deviation, but the total mortality did not differ between these two groups. A highly increased risk of dying was found in groups I, II and IV in patients with exercise associated major ventricular arrhythmias and/or with a small increase of the pressure-rate-product (PRP) during exercise. Patients without arrhythmias and with a high increase of the PRP had a low mortality rate irrespective of their ST-response. In the older patients (70-years-old or more) the ST-response was of no prognostic value at all. The ST-segment response was thus generally of limited value in the prognostic management of the present patients. Their survival was mainly determined by the other exercise variables-the magnitude of an exercise index of left ventricular function and the occurrence of ventricular arrhythmias.