There is some scientific evidence suggesting that certain fatty acids, particularly omega-3 polyunsaturated fatty acids (PUFAs) found in fish oil (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]), may play a role in the prevention or management of certain cardiac arrhythmias, including atrial fibrillation (AF) and palpitations. The proposed mechanisms include stabilization of cardiac cell membranes, modulation of ion channels, and anti-inflammatory effects, which could reduce the risk of abnormal heart rhythms.

However, the strength of the evidence is modest. Early observational studies and some small randomized controlled trials (RCTs) suggested a potential benefit of omega-3 fatty acids in reducing the risk or recurrence of atrial fibrillation, especially postoperative AF. For example, a 2005 study in the American Journal of Cardiology found a reduction in AF recurrence among patients taking fish oil supplements. More recent and larger RCTs, such as the 2010 FORWARD and 2012 OPERA trials, have failed to consistently confirm these benefits, often finding no significant reduction in AF episodes or recurrence. Current meta-analyses point to a possible small protective effect, but results are mixed and not definitive.

There is little evidence that fatty acids are effective for other types of palpitations not caused by arrhythmias. Major cardiology guidelines do not currently recommend omega-3 supplementation specifically for the treatment of AF or palpitations. Thus, while there is a scientific rationale and some supportive data, the overall evidence is limited and inconsistent.