Which ECG changes are associated with hyperkalemia?

Which ECG changes are associated with hyperkalemia?

• A. Prolonged QT interval with U waves
• B. Narrow, peaked T waves, widened P waves, widened QRS, and bradycardia
• C. ST-segment elevations with pathologic Q waves
• D. T wave inversions with QRS widening only

Answer: (B)

Elevated potassium levels slow the heart’s electrical conduction and alter repolarization, producing a characteristic sequence on the ECG. Potassium makes the resting membrane potential less negative, which reduces sodium channel availability and slows conduction through the atrioventricular node and ventricles. This shows up as tall, peaked T waves from faster repolarization, followed by progressive conduction delays: the PR interval lengthens, P waves become flatter or broader, and the QRS complex widens. As hyperkalemia worsens, bradycardia can develop and may progress toward more dangerous rhythms. The pattern described—peaked T waves with widening P waves, QRS broadening, and bradycardia—fits hyperkalemia well, even if the exact descriptor of the T waves can vary (some sources emphasize “tall” or “peaked” T waves).

Elevated potassium levels slow the heart’s electrical conduction and alter repolarization, producing a characteristic sequence on the ECG. Potassium makes the resting membrane potential less negative, which reduces sodium channel availability and slows conduction through the atrioventricular node and ventricles. This shows up as tall, peaked T waves from faster repolarization, followed by progressive conduction delays: the PR interval lengthens, P waves become flatter or broader, and the QRS complex widens. As hyperkalemia worsens, bradycardia can develop and may progress toward more dangerous rhythms. The pattern described—peaked T waves with widening P waves, QRS broadening, and bradycardia—fits hyperkalemia well, even if the exact descriptor of the T waves can vary (some sources emphasize “tall” or “peaked” T waves).