Septal Q wave responses to exertion in the diagnosis of proximal stenosis of the anterior descending coronary artery

In 29 patients with coronary artery disease (CAD) involving the proximal segment of left anterior descending coronary artery (LAD) and in 25 patients with normal coronary anatomy (control group) Q wave amplitude changes were studied in response to exercise with bicycle and treadmill. Decrease of the Q wave amplitude was observed only in the patient group. Increase in amplitude was found only in the control group. The sensitivity of bicycle test for a significant ST segment depression was 51.7%. The same value, obtained by treadmill exercise was 50%. When either a significant ST depression or decrease of Q wave amplitude was evaluated as an abnormal response to exercise, the sensitivity was 62% (bicycle) and 65% (treadmill). Taking both ST segment depression and reduction of Q wave amplitude, an increased sensitivity of exercise ECG examination can ben attained.