The significance of exercise-induced Q waves.

The significance of transient exercise-induced Q waves present during treadmill testing was prospectively evaluated and correlated with the findings at cardiac catheterization. Exercise-induced Q waves were present in 14 of 560 patients (2.5 per cent) undergoing treadmill exercise testing. Thirteen patients had Q waves in leads V1 through V3 and one patient had Q waves in leads II, III and aVF. Ten patients underwent cardiac catheterization; six did not have coronary artery disease as determined by angiography. Two patients had a documented anterior myocardial infarction and did not undergo cardiac catheterization. Exercise myocardial perfusion imaging was performed in 10 patients. Six patients without coronary artery disease had no evidence of exercise perfusion defects. In the four patients with coronary artery disease, three patients had an abnormal resting perfusion study without change with exercise and one patient had a new exercise myocardial perfusion defect. We conclude that exercise-induced transient Q waves are not diagnostic of underlying coronary disease. In patients without coronary artery disease the mechanism of exercise-induced Q waves is as yet unclear. In patients with coronary artery disease, the mechanism may also be undefined or secondary to myocardial ischemia.