Hyperkalemia-like ECG changes simulating acute myocardial infarction in a patient with hypokalemia undergoing potassium replacement.

A pseudo-infarctional ECG pattern, previously noted to occur rarely in association with hyperkalemia, was observed in a patient with severe hypokalemia in the course of K+ replacement but while she was still hypokalemic. It is inferred that this puzzling ECG feature reflected a reduction of intracellular/extracellular [K+] ratio in a patient with decreased intracellular K+ concentration undergoing rapid K+ repletion.