At potassium 7.5-8.5 mmol/L, which ECG change occurs?

At potassium 7.5-8.5 mmol/L, which ECG change occurs?

• A. Sine wave pattern
• B. Tall tented T waves
• C. Loss of P waves
• D. ST-segment elevation

Answer: (D)

Hyperkalemia changes how cardiac cells conduct electricity, so as potassium climbs, the heart’s electrical activity tends to show faster initial repolarization. At a level around 7.5–8.5 mmol/L, the classic ECG finding is tall, peaked (tent-shaped) T waves produced by this accelerated repolarization. You might also begin to see changes like PR prolongation and later widening of the QRS as potassium rises further, but the most characteristic sign in this range is the tall, tented T waves. Sine wave patterns appear only with more extreme hyperkalemia, where the QRS widens and merges with the T wave. Loss of P waves and ST-segment elevation aren’t the hallmark changes for this potassium range; they can occur with progression or in different contexts, respectively.

Hyperkalemia changes how cardiac cells conduct electricity, so as potassium climbs, the heart’s electrical activity tends to show faster initial repolarization. At a level around 7.5–8.5 mmol/L, the classic ECG finding is tall, peaked (tent-shaped) T waves produced by this accelerated repolarization. You might also begin to see changes like PR prolongation and later widening of the QRS as potassium rises further, but the most characteristic sign in this range is the tall, tented T waves.

Sine wave patterns appear only with more extreme hyperkalemia, where the QRS widens and merges with the T wave. Loss of P waves and ST-segment elevation aren’t the hallmark changes for this potassium range; they can occur with progression or in different contexts, respectively.