A 55-year-old man with heart failure is found to have QTc of 480 ms on routine ECG. He is on furosemide, ramipril, bisoprolol, spironolactone, and

Question

A 55-year-old man with heart failure is found to have QTc of 480 ms on routine ECG. He is on furosemide, ramipril, bisoprolol, spironolactone, and dapagliflozin. K⁺ is 4.8 mmol/L, Mg²⁺ is 0.7 mmol/L (low). He has no symptoms of arrhythmia. What is the most likely cause of QT prolongation?

Accepted Answer

Hypomagnesaemia

Answer

Hypokalaemia

Answer

Hypothyroidism

Answer

Congenital long QT syndrome

Answer

Drug-induced QT prolongation

Hypomagnesaemia QT Prolongation — RACP Adult Medicine MCQ

A 55-year-old man with heart failure is found to have QTc of 480 ms on routine ECG. He is on furosemide, ramipril, bisoprolol, spironolactone, and dapagliflozin. K⁺ is 4.8 mmol/L, Mg²⁺ is 0.7 mmol/L (low). He has no symptoms of arrhythmia. What is the most likely cause of QT prolongation?