Divine Intervention IM Shelf Practice Test

A prolonged QT interval can be influenced by various electrolyte imbalances, particularly those involving potassium and magnesium. Both hypomagnesemia and hypokalemia are known to cause disturbances in cardiac repolarization, which is reflected in an extended QT interval on an electrocardiogram.

Hypokalemia reduces potassium levels in the body, which is critical for normal cardiac electrical activity. Low potassium levels can lead to delayed repolarization, manifesting as a prolonged QT interval. Similarly, hypomagnesemia can interfere with potassium channels and overall cardiac function, further exacerbating issues related to repolarization.

This specific combination of electrolyte imbalances effectively impacts the heart's electrical conduction system, resulting in a longer QT interval, which can increase the risk of arrhythmias. Other choices may include conditions that do not correlate as directly with QT interval prolongation, focusing instead on other aspects of electrolyte balance.