What is the sine-wave pattern on ECG, and what electrolyte abnormality does it indicate?

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Multiple Choice

What is the sine-wave pattern on ECG, and what electrolyte abnormality does it indicate?

The sine-wave pattern on ECG is a late, life-threatening sign of severe hyperkalemia. As extracellular potassium rises, the cardiac myocyte resting potential becomes less negative, sodium channels inactivate, and conduction slows. The ECG progresses from tall, peaked T waves with possible PR prolongation to widening of the QRS, and finally the QRS and T waves merge into a smooth sine-wave appearance. This pattern signals impending ventricular fibrillation or asystole and requires urgent treatment to lower potassium and stabilize the heart. Early signs such as peaked T waves are typical of hyperkalemia but not yet this severe pattern, while a flatline indicates true asystole, and digoxin-related rhythm changes are a separate issue.

The sine-wave pattern on ECG is a late, life-threatening sign of severe hyperkalemia. As extracellular potassium rises, the cardiac myocyte resting potential becomes less negative, sodium channels inactivate, and conduction slows. The ECG progresses from tall, peaked T waves with possible PR prolongation to widening of the QRS, and finally the QRS and T waves merge into a smooth sine-wave appearance. This pattern signals impending ventricular fibrillation or asystole and requires urgent treatment to lower potassium and stabilize the heart. Early signs such as peaked T waves are typical of hyperkalemia but not yet this severe pattern, while a flatline indicates true asystole, and digoxin-related rhythm changes are a separate issue.

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