Clinical significance of the ST-segment response and other early exercise test variables in uncomplicated vs complicated myocardial infarction.

An exercise test was performed in 455 patients in the third week after acute myocardial infarction (AMI). One hundred and seventeen (26%) of them were considered as having a complicated AMI. During a follow-up of 4.5 years their mortality was 49% vs 23% in the remaining patients with uncomplicated AMI. The survival of the patients was assessed in each clinical group in relation to various exercise variables. Exercise-induced ST-segment depression, irrespective of its degree, did not discriminate significantly between dead and living patients in any of the clinical groups. A high value of the rise of the pressure-rate product (PRP) from rest to maximal exercise (dPRP) and absence of significant exercise-induced ventricular arrhythmias identified in both clinical groups patients with a very low risk of dying. A low dPRP and/or occurrence of significant ventricular arrhythmias identified a relatively high risk in uncomplicated AMI patients and a very high risk of dying in complicated AMI subjects. The difference in the probability of survival between low-risk and high-risk patients was highly significant in each clinical group (P less than 0.0001 in uncomplicated, and less than 0.005 in complicated AMI, respectively).