Omega-3 fatty acids, particularly EPA and DHA from fish oil, have been studied for their potential effects on heart rhythm disorders such as atrial fibrillation and palpitations. The scientific interest originated from epidemiological studies linking high fish consumption to lower rates of sudden cardiac death and arrhythmias. Early clinical trials and animal studies suggested that omega-3s might stabilize cardiac cell membranes and reduce the risk of arrhythmias, leading to their use as a supportive therapy for heart rhythm problems.

However, more recent and larger randomized controlled trials have produced mixed or negative results. For example, the 2021 OMEMI trial and the 2021 STRENGTH and REDUCE-IT trials (which examined high-dose omega-3s) found no significant reduction in the risk of atrial fibrillation, and some even suggested a possible increase in risk for new-onset atrial fibrillation. The American Heart Association acknowledges that omega-3s may have a modest benefit for certain arrhythmias but does not recommend them specifically for the prevention or treatment of atrial fibrillation.

In summary, while omega-3s have a scientific basis for their study in heart rhythm disorders, the current evidence does not strongly support their use for treating or preventing heart fibrillation or palpitations, and routine supplementation is not broadly recommended for this indication.