Efficacy and Safety of Intravenous Amiodarone Infusion in Japanese Patients with Hemodynamically Compromised Ventricular Tachycardia or Ventricular Fibrillation

Introduction: Amiodarone infusion has been recommended for life-threatening ventricular arrhythmias. However its effectiveness in Japanese patients has not yet been determined. Methods: This was an uncontrolled, open-label trial involving patients with hemodynamically unstable ventricular tachycardia (VT) or ventricular fibrillation (VF). Intravenous amiodarone was delivered as a 125 mg bolus followed by infusion of 50 mg/h for 6 hours, then 25 mg/h for 42 hours. The primary endpoint for efficacy was the proportion of patients free from hemodynamically unstable VT/VF at 48-hour. Secondary endpoints included: event frequency; proportion of patients event-free, treatment outcome, and safety. Results: Forty-seven patients were enrolled. Forty-one patients were evaluated for efficacy and safety parameters were assessed for all 47 patients. The proportion of patients free from hemodynamically unstable VT/VF was 53.9%; the proportion of patients free from hemodynamically unstable VT/VF relapse or whose treatment was discontinued was 48.8%. Eight patients died; all deaths were judged, by the investigator, as being unrelated to amiodarone. No cases of torsades de pointes were reported. Mild abnormal thyroid function was noted in one patient. No cases of interstitial lung disease or pulmonary fibrosis were observed. Conclusion: Amiodarone infusion provides a useful tool in preventing acute relapse of lifethreatening ventricular arrhythmias in Japanese patients.