Positive treadmill stress tests post myocardial infarction in patients with single-vessel coronary disease

To investigate the possibility that patients with single-vessel coronary artery disease (CAD) and recent myocardial infarction (MI) can have ST segment depression on post infarction treadmill testing due to ischemia, we studied 16 such patients who underwent cardiac catheterization and exercise testing after MI. Of the 11 patients with ST segment depression on treadmill testing, 10 failed to increase their ejection fraction and nine had a focal worsening of wall motion during exercise radionuclide ventriculography. Seven of these 11 patients had hypokinesis or normokinesis in the suspected area of infarction. In contrast, four of the five patients without ST segment depression on treadmill stress testing had an increase in ejection fraction with stress which was significantly greater than that seen in patients with ST depression (7.2% vs 0%, p less than 0.05). Short-term follow-up (1.1 years) revealed continued post infarction angina in 10 of the 11 patients with positive treadmill stress tests. Four of these patients underwent either percutaneous transluminal angioplasty or surgery. We conclude that positive post infarction treadmill tests due to exercise-induced ischemia may occur in patients with single-vessel CAD and may be associated with continued angina that requires surgical intervention.