A patient presents with hypokalemia, which can lead to a condition characterized by a prolonged QT interval on the electrocardiogram. What is the primary mechanism by which hypokalemia affects cardiac function?

A Decreased sodium-potassium ATPase activity ✓
B Increased potassium channel activity
C Enhanced calcium channel activity
D Reduced L-type calcium channel activity

Explanation

Hypokalemia decreases sodium-potassium ATPase activity, leading to a prolonged QT interval and affecting cardiac function.

Mnemonic

'Low Potassium = Low ATPase'

Source

Harrison's Principles of Internal Medicine
Electrolytes and Acid-Base Balance Cardiology Electrolyte Imbalance and Cardiac Function Medium NURSING Confidence: medium