n-3 polyunsaturated fatty acids (fish oil) after myocardial infarction

Last reviewed 07/2022

There is contrasting evidence for the benefits of omega -3 fatty acids (n-3 polyunsaturated fatty acids) in patients with ischaemic heart disease

Asystematic review of the literature on the effects of omega-3 fatty acids (n-3 FAs) (consumed as fish or fish oils rich in eicosapentaenoic acid and docosahexaenoic acid or as alpha-linolenic acid) on cardiovascular disease outcomes and adverse events was conducted (1)

  • the authors concluded that the evidence suggests that increased consumption of n-3 FAs from fish or fish-oil supplements, but not of alpha-linolenic acid, reduces the rates of all-cause mortality, cardiac and sudden death, and possibly stroke. The evidence for the benefits of fish oil is stronger in secondary- than in primary-prevention settings

n-3 PUFAs and arrhythmias

  • some authors state that the early effect of low-dose (1 g/d) omega-3 fatty acids on total mortality and sudden death supports the hypothesis of an antiarrhythmic effect of this drug. Such a result is consistent with the wealth of evidence coming from laboratory experiments on isolated myocytes, animal models, and epidemiological and clinical studies (2)
  • a systematic review and meta-analysis investigating the role of fish oil on arrhythmias and mortality however concluded that (3):
    • fish oil supplementation was associated with a significant reduction in deaths from cardiac causes but had no effect on arrhythmias or all cause mortality

n-3 PUFAs in chronic heart failure

  • there is evidence from the GISS-HF Investigators that n-3 PUFAs reduce morbidity and mortality in chronic heart failure (4)
  • note however that:

    • among patients with a recent episode of sustained ventricular arrhythmia and an implantable cardioverter defibrillator (ICD), fish oil supplementation did not reduce the risk of ventricular tachycardia (VT)/ ventricular fibrillation (VF) and may be proarrhythmic in some patients (5)

NICE state (6):

  • do not offer or advise people to use the following to prevent another MI:
    • omega-3 fatty acid capsules
    • omega-3 fatty acid supplemented foods