title: Fish oil supplementation and risk of ventricular tachycardia and ventricular fibrillation in patients with implantable defibrillators: a randomized controlled trial.
abstract: BACKGROUND
  Clinical studies of omega-3 polyunsaturated fatty acids (PUFAs) have shown a reduction in sudden cardiac death, suggesting that omega-3 PUFAs may have antiarrhythmic effects.
  
  
  OBJECTIVE
  To determine whether omega-3 PUFAs have beneficial antiarrhythmic effects in patients with a history of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF).
  
  
  METHODS
  Randomized, double-blind, placebo-controlled trial performed at 6 US medical centers with enrollment from February 1999 until January 2003.
  
  
  METHODS
  Two hundred patients with an implantable cardioverter defibrillator (ICD) and a recent episode of sustained VT or VF.
  
  
  METHODS
  Patients were randomly assigned to receive fish oil, 1.8 g/d, 72% omega-3 PUFAs, or placebo and were followed up for a median of 718 days (range, 20-828 days).
  
  
  METHODS
  Time to first episode of ICD treatment for VT/VF, changes in red blood cell concentrations of omega-3 PUFAs, frequency of recurrent VT/VF events, and predetermined subgroup analyses.
  
  
  RESULTS
  Patients randomized to receive fish oil had an increase in the mean percentage of omega-3 PUFAs in red blood cell membranes from 4.7% to 8.3% (P<.001), with no change observed in patients receiving placebo. At 6, 12, and 24 months, 46% (SE, 5%), 51% (5%), and 65% (5%) of patients randomized to receive fish oil had ICD therapy for VT/VF compared with 36% (5%), 41% (5%), and 59% (5%) for patients randomized to receive placebo (P = .19). In the subset of 133 patients whose qualifying arrhythmia was VT, 61% (SE, 6%), 66% (6%), and 79% (6%) of patients in the fish oil group had VT/VF at 6, 12, and 24 months compared with 37% (6%), 43% (6%), and 65% (6%) of patients in the control group (P = .007). Recurrent VT/VF events were more common in patients randomized to receive fish oil (P<.001).
  
  
  CONCLUSIONS
  Among patients with a recent episode of sustained ventricular arrhythmia and an ICD, fish oil supplementation does not reduce the risk of VT/VF and may be proarrhythmic in some patients.
authors.affiliation: Oregon Health and Science University, Portland, USA. merritt.raitt@med.va.gov
authors.forename: Merritt H
authors.initials: MH
authors.lastname: Raitt
authors.forename: William E
authors.initials: WE
authors.lastname: Connor
authors.forename: Cynthia
authors.initials: C
authors.lastname: Morris
authors.forename: Jack
authors.initials: J
authors.lastname: Kron
authors.forename: Blair
authors.initials: B
authors.lastname: Halperin
authors.forename: Sumeet S
authors.initials: SS
authors.lastname: Chugh
authors.forename: James
authors.initials: J
authors.lastname: McClelland
authors.forename: James
authors.initials: J
authors.lastname: Cook
authors.forename: Karen
authors.initials: K
authors.lastname: MacMurdy
authors.forename: Robert
authors.initials: R
authors.lastname: Swenson
authors.forename: Sonja L
authors.initials: SL
authors.lastname: Connor
authors.forename: Glenn
authors.initials: G
authors.lastname: Gerhard
authors.forename: Dale F
authors.initials: DF
authors.lastname: Kraemer
authors.forename: Daniel
authors.initials: D
authors.lastname: Oseran
authors.forename: Christy
authors.initials: C
authors.lastname: Marchant
authors.forename: David
authors.initials: D
authors.lastname: Calhoun
authors.forename: Reed
authors.initials: R
authors.lastname: Shnider
authors.forename: John
authors.initials: J
authors.lastname: McAnulty
mesh_terms: D000368:Aged; D017147:Defibrillators, Implantable; D019587:Dietary Supplements; D004311:Double-Blind Method; D004910:Erythrocyte Membrane / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012306:Risk; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000517:prevention & control / Q000628:therapy*; D014693:Ventricular Fibrillation / Q000517:prevention & control / Q000628:therapy*
chemical_list: D015525:Fatty Acids, Omega-3