Fatality due to intravenous diltiazem for acute ventricular rate control

Progressive, sustained bradycardia resulting in asystole and subsequent death is reported in a 70-year-old woman with hyperkalemia and suspected digoxin toxicity following a 0.25 mg/kg intravenous diltiazem dose for treatment of atrial fibrillation with a rapid ventricular response. The possible pharmacodynamic and pharmacokinetic interactions between diltiazem, digoxin, and an elevated plasma potassium concentration are discussed and related to the outcome of the case. The routine practice of concomitant administration of diltiazem for rapid ventricular rate control and digoxin for long-term control may be dangerous in a subset of patients.