Which statement describes the ECG changes typical of hypokalemia?

Which statement describes the ECG changes typical of hypokalemia?

• A. Hyperkalemia
• B. Flattened T waves and U waves
• C. Peaked T waves
• D. ST-segment elevation

Answer: (B)

Low potassium slows ventricular repolarization, changing how the ECG looks. When potassium is low, the T wave becomes flatter and a U wave often appears after the T wave. The U wave is an extra deflection that reflects delayed repolarization of parts of the ventricles. You may also see ST-segment depression and a longer QT interval as potassium falls. By contrast, tall, peaked T waves point to high potassium, and ST-segment elevation is usually related to acute myocardial injury, not hypokalemia. So, flattened T waves with a prominent U wave best describe the ECG changes in hypokalemia.

Low potassium slows ventricular repolarization, changing how the ECG looks. When potassium is low, the T wave becomes flatter and a U wave often appears after the T wave. The U wave is an extra deflection that reflects delayed repolarization of parts of the ventricles. You may also see ST-segment depression and a longer QT interval as potassium falls. By contrast, tall, peaked T waves point to high potassium, and ST-segment elevation is usually related to acute myocardial injury, not hypokalemia. So, flattened T waves with a prominent U wave best describe the ECG changes in hypokalemia.