Inverted U-wave and myocardial ischemia

An 87-year-old woman had a routine medical examination. She complained of slight dyspnea on exertion. The physical examination revealed no pathological findings. Her blood pressure was 140/80 mmHg. Laboratory tests were within normal ranges. The electrocardiogram revealed an inverted U-wave in leads V3–V5 (Figure 1A, arrow). Ten days later, she complained of severe dyspnea at rest. The electrocardiogram showed poor R-wave progression in leads V1–V3 and subtle ST segment elevation in leads V2–V4. Two-dimensional echocardiography revealed severe hypokinesis in the anteroapical region. Significant changes in heart valve function were not observed. Coronary angiography revealed multi-vessel coronary artery disease involving the left anterior descending artery (Figure 1B, arrow). Her hemodynamic state did not improve despite treatment with diuretics, catecholamines and mechanical ventilator support. Coronary revascularization after the insertion of an intra-aortic balloon pump was performed to treat refractory heart failure. (A) Electrocardiogram showing inverted U-waves (arrow). (B) Coronary angiography showing severe stenosis of the left anterior descending artery (arrow). The origin of the U-wave was unclear. There are several mechanisms that could account for a U-wave: (1) delayed repolarization of the His-Purkinje system, (2) prolonged repolarization of mid-myocardial M cells and (3) after-potentials caused by ventricular stretch.1 The U-wave normally has the same polarity as the T-wave. Inversion of the U-wave with an upright T-wave has pathological significance. An inverted U-wave appears in various pathological conditions, including myocardial ischemia,2 coronary vasospasm,3 valvular disease, hypertension and cardiomyopathy. Transient changes in the precordial leads often reflect ischemia in the left anterior descending artery region. In this patient, the inverted U-wave disappeared after treatment. Conflict of interest: None declared.