Fish oil supplementation and risk of ventricular tachycardia and ventricular fibrillation in patients with implantable defibrillators: a randomized controlled trial.
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.
Raitt
Merritt H
MH
Oregon Health and Science University, Portland, USA. merritt.raitt@med.va.gov
Connor
William E
WE
Morris
Cynthia
C
Kron
Jack
J
Halperin
Blair
B
Chugh
Sumeet S
SS
McClelland
James
J
Cook
James
J
MacMurdy
Karen
K
Swenson
Robert
R
Connor
Sonja L
SL
Gerhard
Glenn
G
Kraemer
Dale F
DF
Oseran
Daniel
D
Marchant
Christy
C
Calhoun
David
D
Shnider
Reed
R
McAnulty
John
J
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*
D015525:Fatty Acids, Omega-3