Hypercalcemia can cause which ECG change?

Hypercalcemia can cause which ECG change?

• A. Prolonged QT interval
• B. Shortened QT interval
• C. ST segment elevation
• D. T wave inversion

Answer: (B)

Hypercalcemia speeds up ventricular repolarization, shortening the duration of the plateau phase in the cardiac action potential. This makes the end of ventricular repolarization occur sooner, so the QT interval on the ECG is shortened. The QT interval spans from the start of the QRS complex to the end of the T wave, so a faster repolarization shortens that interval. Prolonged QT occurs with low calcium, not high. ST segment elevation and T wave inversion are associated with ischemia or other conditions, not specifically with elevated calcium levels.

Hypercalcemia speeds up ventricular repolarization, shortening the duration of the plateau phase in the cardiac action potential. This makes the end of ventricular repolarization occur sooner, so the QT interval on the ECG is shortened. The QT interval spans from the start of the QRS complex to the end of the T wave, so a faster repolarization shortens that interval.

Prolonged QT occurs with low calcium, not high. ST segment elevation and T wave inversion are associated with ischemia or other conditions, not specifically with elevated calcium levels.