title: Prevention of fatal arrhythmias in high-risk subjects by fish oil n-3 fatty acid intake.
abstract: BACKGROUND
  The long-chain n-3 fatty acids in fish have been demonstrated to have antiarrhythmic properties in experimental models and to prevent sudden cardiac death in a randomized trial of post-myocardial infarction patients. Therefore, we hypothesized that these n-3 fatty acids might prevent potentially fatal ventricular arrhythmias in high-risk patients.
  
  
  RESULTS
  Four hundred two patients with implanted cardioverter/defibrillators (ICDs) were randomly assigned to double-blind treatment with either a fish oil or an olive oil daily supplement for 12 months. The primary end point, time to first ICD event for ventricular tachycardia or fibrillation (VT or VF) confirmed by stored electrograms or death from any cause, was analyzed by intention to treat. Secondary analyses were performed for "probable" ventricular arrhythmias, "on-treatment" analyses for all subjects who had taken any of their oil supplements, and "on-treatment" analyses only of those subjects who were on treatment for at least 11 months. Compliance with double-blind treatment was similar in the 2 groups; however, the noncompliance rate was high (35% of all enrollees). In the primary analysis, assignment to treatment with the fish oil supplement showed a trend toward a prolonged time to the first ICD event (VT or VF) or of death from any cause (risk reduction of 28%; P=0.057). When therapies for probable episodes of VT or VF were included, the risk reduction became significant at 31%; P=0.033. For those who stayed on protocol for at least 11 months, the antiarrhythmic benefit of fish oil was improved for those with confirmed events (risk reduction of 38%; P=0.034).
  
  
  CONCLUSIONS
  Although significance was not achieved for the primary end point, this study provides evidence that for individuals at high risk of fatal ventricular arrhythmias, regular daily ingestion of fish oil fatty acids may significantly reduce potentially fatal ventricular arrhythmias.
authors.affiliation: Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. aleaf@partners.org
authors.forename: Alexander
authors.initials: A
authors.lastname: Leaf
authors.forename: Christine M
authors.initials: CM
authors.lastname: Albert
authors.forename: Mark
authors.initials: M
authors.lastname: Josephson
authors.forename: David
authors.initials: D
authors.lastname: Steinhaus
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kluger
authors.forename: Jing X
authors.initials: JX
authors.lastname: Kang
authors.forename: Benjamin
authors.initials: B
authors.lastname: Cox
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: David
authors.initials: D
authors.lastname: Schoenfeld
mesh_terms: D000328:Adult; D017147:Defibrillators, Implantable; D019587:Dietary Supplements; D004311:Double-Blind Method; D015525:Fatty Acids, Omega-3 / Q000627:therapeutic use*; D005260:Female; D005395:Fish Oils; D006801:Humans; D008297:Male; D008875:Middle Aged; D000069463:Olive Oil; D010938:Plant Oils / Q000627:therapeutic use; D016019:Survival Analysis; D013610:Tachycardia / Q000401:mortality / Q000517:prevention & control*; D014693:Ventricular Fibrillation / Q000401:mortality / Q000517:prevention & control*
chemical_list: D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D000069463:Olive Oil; D010938:Plant Oils