[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.