Efficacy of Additional Amiodarone Therapy in Patients with an Implantable Cardioverter-Defibrillator

Introduction: We examined whether the additional use of amiodarone (AMD) under implantable cardioverter-defibrillator (ICD) therapy may have beneficial effects in patients at risk for lethal ventricular arrhythmias with structural heart diseases. Methods: Sixty patients (47 males, mean age, 62 ± 13 years) with structural heart disease who underwent ICD implantation were retrospectively analyzed. There were 2 groups: one group (AMD group) was treated with AMD (n = 33) and the other group (non-AMD group) was treated without AMD (n = 27). We compared the incidence and appropriateness of ICD shock therapy between two groups. Results: During a mean follow-up of 28 ± 17 months, we identified a total of 62 episodes in 18 patients (30%) who received ICD shock therapy. ICD shock episodes were significantly less frequent in AMD group than in non-AMD group (15% versus 48%, P < 0.01), while inappropriate shock episodes were greater in non-AMD group than in AMD group (49% versus 4%, P = 0.03). In cumulative probability of shock events, the risk of events was significantly lower in AMD group (P = 0.007). Of 4 patients who died in AMD group, we observed one fatal pulmonary fibrosis. Conclusions: Additional AMD therapy in patients with an ICD may be effective in reducing the risk of shock discharge.