T-wave inversion on an ECG is most suggestive of which condition?

• A. Ischemia
• B. Normal in aVR
• C. Hyperkalemia
• D. Pericarditis

Answer: (A)

T-wave inversion signals abnormal repolarization from reduced blood flow to the heart muscle. When a region becomes ischemic, the electrical recovery of that area alters the direction of the T wave in the leads facing the affected territory. In the clinical setting of chest pain or risk factors, new or dynamic T-wave inversions are most suggestive of myocardial ischemia or a NSTEMI, especially when they correspond to the territory at risk.

Hyperkalemia typically makes T waves tall and peaked rather than inverted. Pericarditis usually presents with diffuse ST-segment elevation and PR-segment depression, with T-wave changes that may occur later. The lead aVR normally has an inverted T wave even in healthy people, so inversion there alone isn’t diagnostic of ischemia. Thus, the pattern of T-wave inversion most closely points to ischemia.