Severe Hypokalemia With Large U-Wave Mimicking Benign T-Wave in an Elderly Alcoholic Woman

A woman in her late sixties with chronic alcoholism presented with nausea, vomiting, and weakness, found to have severe hypokalemia (K⁺ 2.0 mEq/L) and a prolonged QTc (673 ms). Initial electrocardiogram (ECG) revealed a prominent U-wave overlaying a shallow T-wave, mimicking a paradoxically large T-wave. With the striking ECG findings, her hypokalemia was corrected with potassium supplementation. A follow-up ECG post-resolution showed normalized T-wave morphology, confirming the U-wave's role. This case highlights the diagnostic challenge of U waves in hypokalemia and the importance of serial ECGs in management.