Omega-3 fatty acid: a role in the management of cardiac arrhythmias?

OBJECTIVE The objective of this study was to review and evaluate published evidence on the use of omega-3 fatty acid in the prevention and treatment of atrial and ventricular arrhythmias. Postulated mechanisms of the antiarrhythmic effects of omega-3 fatty acid are discussed. DATA SOURCES Peer-reviewed articles/abstracts published in English language were identified from MEDLINE and Current Content databases (both 1966 to May 15, 2008) using the search terms fish oil, omega-3 fatty acid, sudden death, ventricular arrhythmia, and atrial fibrillation. Citations from available articles were also reviewed for additional references. Abstracts presented at recent professional meetings are also reviewed. STUDY SELECTION AND DATA EXTRACTION Observational studies and interventional clinical studies published on omega-3 fatty acid or fish consumption and atrial or ventricular arrhythmias and sudden cardiac death are selected. The design and results of the studies are evaluated. DATA SYNTHESIS Several mechanisms have been postulated to explain the antiarrhythmic effect of omega-3 fatty acid. It is believed that omega-3 fatty acid has an indirect effect on the autonomic nervous system, inhibits the fast, voltage-dependent sodium and L-type calcium channels, restores a favorable omega-6 fatty acid/omega-3 fatty acid balance, and exerts anti-inflammatory effects. While the majority of observational evidence demonstrated that increased consumption of omega-3 fatty acid was associated with reduction in risk of sudden cardiac death, in ventricular arrhythmia, there was evidence suggesting that omega-3 fatty acid in patients experiencing nonischemic ventricular arrhythmia may be proarrhythmic. Other studies demonstrated a neutral effect. In terms of management of atrial fibrillation, short-term small-scale studies demonstrated that the use of omega-3 fatty acid preoperatively may reduce the incidence of postoperative atrial fibrillation. However, such observations were not consistent with those reported from retrospective cohorts. CONCLUSIONS Additional studies are needed to evaluate the effect of omega-3 fatty acid before it can be routinely recommended for the management of arrhythmia.