Arrhythmias USMLE Step 1 Practice Question
A 77-year-old woman with heart failure and chronic kidney disease presents with nausea, yellow-tinted vision, and palpitations. Vital signs: BP 98/62 mmHg, HR 140/min, RR 20/min, temp 37.2°C, SpO2 98% on room air. ECG shows bidirectional ventricular tachycardia. Serum potassium is 4.2 mEq/L. She denies chest pain. She takes digoxin 0.25 mg daily. Which medication toxicity best explains this arrhythmia?
Answer choices
- AHypocalcemia causing prolonged QT interval
- BAcute pericarditis causing atrial irritability
- CDigoxin toxicity causing delayed afterdepolarizationsCorrect answer
- DCongenital sodium channel mutation in Brugada syndrome
- EAccessory pathway conduction in Wolff-Parkinson-White syndrome
- FHypomagnesemia causing early afterdepolarizations and prolonged repolarization
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