Study on Omega-3 Fatty Acids and Ventricular Arrhythmia - SOFA

Description:

The goal of the trial was to evaluate the efficacy of n-3 polyunsaturated fatty acids (n-3 PUFA) from fish oil on the recurrence of life-threatening ventricular arrhythmias compared with placebo among patients with an implantable cardioverter defibrillator (ICD).

Hypothesis:

Treatment with fish oil (n-3 PUFA) will prevent sudden death by suppressing life-threatening cardiac arrhythmias compared with placebo among patients with an ICD.

Study Design

Study Design:

Patients Screened: 1,828
Patients Enrolled: 546
Mean Follow Up: 12 months
Mean Patient Age: Mean age 61 years
Mean Ejection Fraction: Mean 37% at baseline

Patient Populations:

Age ≥18 years, experienced at least one true and confirmed spontaneous VT/VF in prior year, and ICD capable of recording ECG strips for at least 10 of its (attempted) therapeutic interventions

Exclusions:

Primary prophylactic indication, ICD implantation as a "bridge" to heart transplantation, refractory supraventricular arrhythmias with rapid ventricular rates despite antiarrhythmic therapy, projected lifespan of <1 year, use of any supplemental n-3 fatty acid during the prior 3 months, or intake of >8 g of n-3 fatty acids from fish per month as judged by a fish frequency questionnaire

Primary Endpoints:

Occurrence of appropriate ICD intervention (shock or antitachycardia pacing) for spontaneous ventricular tachyarrhythmias, or all-cause mortality

Secondary Endpoints:

All-cause mortality, cardiac mortality, MI, all arrhythmic events as documented by the ICD core laboratory, and change in the prescription of antiarrhythmic drugs

Drug/Procedures Used:

Patients with an ICD were randomized in a double-blind manner to either 2 g/d of fish oil (n = 273) or placebo oil (n = 273) in a capsule form for a period up to 12 months. The fish oil dose was equal to approximately 3-4 fish meals per week.

Principal Findings:

Baseline characteristics were well-balanced between treatment groups, with 38% having ventricular fibrillation (VF), 75% having ventricular tachycardia (VT), and 63% having a prior myocardial infarction (MI). Baseline ejection fraction was 37%. Antiarrhythmic medication was used in 27% of patients and beta-blockers in 55% of patients.

The primary endpoint of life-threatening arrhythmias or death at 12 months did not differ by treatment group (30% of fish oil group vs. 33% of placebo group, p = 0.33). There were 14 deaths in the placebo group and eight deaths in the fish oil group. Among the subgroup of patients with a prior MI (n = 332), survival free from VT or VF trended better in patients treated with fish oil (hazard ratio 0.76, 95% confidence interval, 0.52-1.11). Results were similar across other subgroups. There were no excess safety concerns in the fish oil group.

Interpretation:

Among patients with an ICD, treatment with fish oil was not associated with a reduction in life-threatening arrhythmias or death at 12 months, despite no apparent safety risk.

Prior observational studies and clinical trials suggested n-3 PUFA from fish was associated with reductions in sudden death, but no reduction in nonfatal heart disease. The majority of sudden deaths are due to acute ventricular arrhythmia. Patients with an ICD, which records all arrhythmic events in a memory chip, allows for the continuous monitoring of arrhythmic events and provided a population to evaluate whether fish oil did indeed have antiarrhythmic properties. While there was no benefit overall, the subgroup of patients with prior MI showed a trend toward benefit, although these data should be interpreted with caution and seen more as a potential target population for further study.

References:

Brouwer IA, Zock PL, Camm AJ, et al. Effect of fish oil on ventricular tachyarrhythmia and death in patients with implantable cardioverter defibrillators: the Study on Omega-3 Fatty Acids and Ventricular Arrhythmia (SOFA) randomized trial. JAMA 2006;295:2613-2619.

Presented by Dr. Ingeborg Brouwer at the European Society of Cardiology Hot Line Session, September 2005.

Clinical Topics: Arrhythmias and Clinical EP, Dyslipidemia, Implantable Devices, SCD/Ventricular Arrhythmias, Lipid Metabolism, Nonstatins

Keywords: Myocardial Infarction, Tachycardia, Ventricular, Fatty Acids, Omega-3, Ventricular Fibrillation, Health Services Needs and Demand, Confidence Intervals, Electrocardiography, Death, Sudden, Cardiac, Defibrillators, Implantable


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