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Significance of treadmill stress testing in transmural myocardial infarction. Correlation with coronary angiography.

To assess the usefulness of stress testing in predicting multivessel coronary disease and left ventricular dysfunction, 83 male patients with a myocardial infarction one to 84 months previously were studied.

In inferior infarction (45 patients), the ST segment depression had a sensitivity of 91% and a specificity of 77% to detect multivessel disease. Patients with multivessel disease had significantly lower exercise capacity and maximal heart rates. ST segment elevation showed a poor correlation with the number of affected vessels.

In anterior infarction (38 patients), both ST segment depression and elevation were of little value to detect multivessel disease. However, the predictive value of an exercise test without ST segment changes to exclude multivessel disease was 89%; on the other hand, patients without ST segment changes had significantly higher ejection fractions, exercise capacity, maximal heart rates and rate-pressure products than patients with ST segment changes.

Patients with ST segment elevation had significantly lower ejection fractions in both groups. The sensitivity of ST segment elevation to detect severe segmental left ventricular dysfunction was 84% for anterior infarction and 54% for inferior infarction. Specificity was 84 and 85%, respectively.

We conclude that:

(1) exercise-induced ST segment depression is useful to predict the extent of coronary artery disease in inferior infarction, but it is of limited value in anterior infarction,

(2) exercise-induced ST segment elevation correlates well with the presence of severe left ventricular dysfunction in both anterior and inferior infarction, and

(3) an exercise test of considerable intensity without ST segment changes makes the existence of multivessel coronary disease and/or severe left ventricular dysfunction very improbable.