> It is unclear how omega-3 fatty acids increase the AF risk. Omega-3 fatty acids stabilize the cardiac membrane and protect against arrhythmias, including ventricular arrhythmias, through both direct electrophysiologic actions and positive effects on biological processes involved in atrial remodeling. However, omega-3 fatty acids have direct effects on the activity of cardiac calcium, sodium, and potassium ionic currents, which can alter the duration of the ventricular action potential. Therefore, omega-3 fatty acids may promote re-entrant arrhythmias, despite being anti-arrhythmic in therapeutic conditions. Several previous studies have evaluated the electrical characteristics of the ventricular wall; few studies have evaluated how omega-3 fatty acids influence the atria.
It sounds to me like that short quote is saying (paraphrasing here) that 'studies seems to show omega-3 is beneficial, but theoretically apart from the beneficial mechanisms there could be a harmful mechanism so we're not sure why we don't see that happening'
> It is unclear how omega-3 fatty acids increase the AF risk. Omega-3 fatty acids stabilize the cardiac membrane and protect against arrhythmias, including ventricular arrhythmias, through both direct electrophysiologic actions and positive effects on biological processes involved in atrial remodeling. However, omega-3 fatty acids have direct effects on the activity of cardiac calcium, sodium, and potassium ionic currents, which can alter the duration of the ventricular action potential. Therefore, omega-3 fatty acids may promote re-entrant arrhythmias, despite being anti-arrhythmic in therapeutic conditions. Several previous studies have evaluated the electrical characteristics of the ventricular wall; few studies have evaluated how omega-3 fatty acids influence the atria.