The value of postcardiac infarction exercise stress testing: identification of a group at high risk.

We prospectively selected 154 patients who had survived acute myocardial infarction with electrical and/or mechanical complications to undergo an exercise stress test, four to six weeks after discharge from the Coronary Care Unit, Royal Melbourne Hospital. The patients exercised on a bicycle ergometer until they were unable to continue or had reached 70% of their predicted maximum heart rate for their age. Eighteen (11.7%) patients exhibited flat ST-depression of 1 mm or more on exercise. Six of these 18 patients later died (33.3%). Only seven (5.1%) of the 136 patients who exhibited no electrocardiographic change died during follow-up. We conclude that patients recording positive exercise stress test results after acute myocardial infarction, have a poorer prognosis and therefore should be considered for more intensive medical or surgical treatment.