1. In patients with congestive heart failure (CHF) and reduced ejection fraction, mortality was significantly lower in patients who received an implantable cardioverter-defibrillator (ICD) compared those who did not receive one.
2. In these patients, amiodarone did not confer a favorable survival benefit as compared to placebo.
Original Date of Publication: January 2005
Study Rundown: Patients with CHF are at higher risk of sudden cardiac death, often secondary to cardiac arrhythmias, despite being treated with conventional medical therapy. Amiodarone and ICDs were identified as two potential approaches to prevent death in this patient population. Amiodarone had been previously studied in patients with CHF, though the findings were inconclusive. Similarly, some evidence supported the effectiveness of ICDs in this setting, though the trials were small. Moreover, most previous studies had explored the use of amiodarone and ICDs in patients who had recently suffered myocardial infarctions or ventricular arrhythmia, and were not generalizable to patients with CHF who did not experience these events.
The Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) was designed to evaluate amiodarone and ICDs in the treatment of patients with mild-to-moderate CHF. In patients with New York Heart Association (NYHA) class II or III symptoms and left ventricular ejection fraction (LVEF) ≤35%, ICD treatment led to a significant reduction in mortality when compared with placebo. There were no significant differences in mortality when comparing the amiodarone and placebo groups. Although this study suffered from high rates of study drug discontinuation, it provides strong evidence in support of ICDs in patients with stable CHF and reduced LVEF.
In-Depth [randomized controlled trial]: A total of 2521 patients were randomized for this study. All patients ≥18 years of age, with NYHA class II or III symptoms, and with LVEF ≤35% were eligible for the trial. Patients were randomized equally to treatment with placebo, amiodarone (weight-adjusted maintenance dosing after initial loading), or Medtronic single-chamber ICD programmed to shock-only mode. The primary endpoint was death from any cause.
The median follow-up was 45.5 months for all surviving patients. The median dose of amiodarone used was 300 mg daily. A total of 29% of the placebo group, 28% of the amiodarone group, and 22% of the ICD group died during the course of this study. There were no significant differences in mortality between the amiodarone and placebo groups (28% vs. 29%; HR 1.06 97.5%CI 0.86 to 1.30, p = 0.53). Patients treated with ICD experienced significantly lower mortality when compared with those taking placebo (22% vs. 29%; HR 0.77, 97.5%CI 0.62 to 0.96, p = 0.007). Drug discontinuation rates were high, with 22% of the placebo group and 32% of the amiodarone group discontinuing their drug therapies. Patients in the amiodarone group experienced significantly higher rates of tremor (4%, p = 0.02) and hypothyroidism (6%, p < 0.001). Approximately 5% of patients receiving ICDs experienced a significant complication at the time of implantation (surgical correction, hospitalization, new/unanticipated drug therapy), while 9% of patients experienced such complications later.
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