Pseudo ST segment elevation and terminal negative deflection of T wave during treadmill test could be due to damping problem in the printer

Abstract

ST segment elevation during treadmill stress testing, in the leads without Q waves, is considered suggestive of transmural ischemia due to high grade proximal coronary arterial lesions. We observed six consecutive, asymptomatic individuals who had ST segment elevation and terminal negative deflection of the T waves in leads V1 to V3 during treadmill stress testing. Resting electrocardiograms recorded from another machine just before treadmill test were normal. Detailed echocardiographic evaluation just before treadmill test did not reveal any regional wall motion abnormalities in any case. All patients could complete the stress test without any clinical or electrocardiographic signs of ischemia. After careful analysis of resting electrocardiograms, clinical profile, heart rate and blood pressure responses and electrocardiographic findings during stress test, we felt that ST segment elevation and terminal negative deflection of the T wave recorded only during treadmill test were artefacts due to under damping (overshoot) of the stylus of the printer of the particular treadmill stress test system. Detailed findings are given and differential diagnosis is discussed. Repair resulted in normal tracing in subsequent patients. Keywords: Artefacts; Electrocardiography; Stress test; ST segment; T wave; Treadmill test