Severe hypercalcemia from multiple myeloma as an acquired cause of short QT

An otherwise healthy 64-year-old man with recently diagnosed multiple myeloma was admitted to hospital with hypercalcemia and renal failure. Despite his electrocardiogram showing short QT/QTc intervals, he was admitted without cardiac monitoring. He died suddenly a few hours later, likely from a fatal arrhythmia. This case illustrates that pronounced QT shortening from hypercalcemia is an underappreciated malignant finding that can portend a significant risk for arrhythmia and sudden cardiac death. In addition, we also discuss the causes of hypercalcemia associated short QT/QTc intervals and its ECG features.