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

A n exercise test was made in 317 patients in the third weekafter acute myocardial infarction. The following types of exerciseassociated ST-segment responses were registered in patientsless 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 groupHI than in groups II and ' IV. Group IV had a significantlyhigher 5-year mortality than all the other groups. Patientswith ST-depression had an increased late mortality comparedto that of the patients without ST-deviation, but the totalmortality did not differ between these two groups. A highlyincreased risk of dying was found in groups I, II and IV inpatients with exercise associated major ventricular arrhythmiasand/or with a small increase of the pressure-rate-product (PRP)during exercise. Patients without arrhythmias and with a highincrease of the PRP had a low mortality rale irrespective oftheir ST-response. In the older patients (70-years-old or more)the ST-response was of no prognostic value at all. The ST-segmentresponse was thus generally of limited value in the prognosticmanagement of the present patients. Their survival was mainlydetermined by the other exercise variables-the magnitude ofan exercise index of left ventricular function and the occurrenceof ventricular arrhythmia