What are the hyperkalemia electrocardiographic changes?

• A. Peaked T waves, prolonged PR, loss of P waves, widening QRS; calcium chloride or calcium gluconate
• B. U waves
• C. ST elevations
• D. Peaked T waves, prolonged PR, loss of P waves, widening QRS; calcium chloride or calcium gluconate

Answer: (D)

Hyperkalemia alters cardiac conduction by changing the resting membrane potential, leading to a characteristic progression of ECG changes. Early on you see tall, peaked T waves as repolarization accelerates. As potassium level rises, conduction slows: the PR interval lengthens, the P waves become smaller and eventually disappear, and the QRS complex widens as depolarization through the ventricles is delayed. If potassium continues to climb, the QRS and T waves can merge into a sine-wave pattern, creating a dangerous rhythm disturbance. The immediate, temporizing treatment is calcium administration (calcium chloride or calcium gluconate) to stabilize myocardial membranes and reduce the risk of arrhythmias, while definitive therapy lowers the potassium. Other options don’t fit hyperkalemia’s typical ECG picture: U waves suggest hypokalemia, and ST elevations point to ischemia or inflammation rather than hyperkalemia.