digoxin

A 72-year-old man with a history of chronic heart failure with reduced ejection fraction (HFrEF) and atrial fibrillation presents to the cardiology clinic for routine follow-up. He reports increased fatigue and occasional palpitations but denies chest pain or syncope. His current medications include lisinopril, carvedilol, furosemide, and digoxin. His blood pressure is 110/70 mmHg, heart rate is 78 bpm, and he has mild peripheral edema. Recent laboratory tests show a serum creatinine of 1.2 mg/dL and potassium of 4.5 mmol/L. An echocardiogram shows an ejection fraction of 35%. Considering his current medication regimen and clinical status, which of the following is the most appropriate next step in his pharmacological management?

A 72-year-old man with a history of heart failure and hypertension is admitted to the hospital with pneumonia. His medications include furosemide, ramipril, and digoxin. On day 3 of admission, he develops new-onset polymorphic ventricular tachycardia (Torsades de Pointes). An ECG shows a QTc interval of 580 ms. Which of the following is the MOST likely contributing factor to his arrhythmia?

A 78-year-old woman with a history of heart failure (reduced ejection fraction), type 2 diabetes, and recent hospitalisation for pneumonia presents to her GP with increasing fatigue and a single episode of dizziness leading to a fall without loss of consciousness. Her current medications are Digoxin 125 mcg daily, Furosemide 40 mg daily, Ramipril 5 mg daily, Metformin 500 mg BD, and Amoxicillin 500 mg TDS (started 5 days ago for pneumonia). An ECG in clinic shows sinus rhythm, rate 70 bpm, and a QTc of 530 ms. An ECG from 6 months prior had a QTc of 440 ms. Recent laboratory tests show Na 138 mmol/L, K 4.2 mmol/L, Mg 0.9 mmol/L, Ca 2.3 mmol/L, Creatinine 90 µmol/L, and Digoxin level 1.1 ng/mL. Considering the clinical context and investigations, which of the following is the most likely significant contributor to the observed QTc prolongation?