Can n-3 PUFA reduce cardiac arrhythmias? Results of a clinical trial

Prostaglandins Leukot Essent Fatty Acids. 2004 Sep;71(3):153-9. doi: 10.1016/j.plefa.2004.03.003.


Dietary n-3 polyunsaturated fatty acids (PUFA) derived from fatty fish or fish oil may reduce the incidence of lethal myocardial infarction and sudden cardiac death. This might be due to a prevention of fatal cardiac arrhythmias. So far, however, only few clinical data are available being adequate to define indications for an antiarrhythmic treatment with n-3 PUFA. In a randomized, double-blind, placebo-controlled study 65 patients with cardiac arrhythmias without coronary heart disease or heart failure were subdivided into 2 groups. One group (n = 33) was supplemented with encapsulated fish oil (3g/day, equivalent to 1g/day of n-3 PUFA) over 6 months. The other group (n = 32) was given 3g/day of olive oil as placebo. In the fish oil group a decrease of serum triglycerides, total cholesterol, LDL cholesterol, plasma free fatty acids and thromboxane B2 as well as an increase of HDL cholesterol were observed. Moreover, a reduced incidence of atrial and ventricular premature complexes, couplets and triplets were documented. Accordingly, higher grades of Lown's classification switched to lower grades at the end of the dietary period. No changes were seen in the placebo group. The data indicate an antiarrhythmic action of n-3 PUFA under conditions of clinical practice which might help to explain the reduced incidence of fatal myocardial infarction and sudden cardiac death in cohorts on a fish-rich diet or supplemented with n-3 PUFA. Further studies elucidating the possible link between the reduced incidence of cardiac arrhythmias and sudden cardiac death by dietary intake of n-3 PUFA are warranted.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Atrial Premature Complexes / blood
  • Atrial Premature Complexes / diet therapy*
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Death, Sudden, Cardiac / etiology
  • Death, Sudden, Cardiac / pathology
  • Death, Sudden, Cardiac / prevention & control
  • Double-Blind Method
  • Fatty Acids, Unsaturated / administration & dosage*
  • Female
  • Humans
  • Lipids / blood
  • Male
  • Middle Aged
  • Myocardial Infarction / blood
  • Myocardial Infarction / diet therapy
  • Myocardial Infarction / etiology
  • Myocardial Infarction / pathology
  • Thromboxane B2 / blood
  • Ventricular Premature Complexes / blood
  • Ventricular Premature Complexes / diet therapy*


  • Cholesterol, HDL
  • Cholesterol, LDL
  • Fatty Acids, Unsaturated
  • Lipids
  • Thromboxane B2