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02-08-2011 | Cardiology | Article

Omega-3 fatty acids have antifibrillatory effect in PAF


Free abstract

MedWire News: Long-term fish oil intake may have an antifibrillatory effect in human paroxysmal atrial fibrillation (PAF), Australian research suggests.

"The finding that patients using fish oil had longer mean and longer shortest recorded effective refractory periods (ERPs) than controls, less dispersion of refractoriness, and longer mean and shortest atrial fibrillation (AF) cycle length suggests that fish oils may be able to attenuate arrhythmogenic substrate for AF in the pulmonary veins (PVs)," remark the researchers.

Writing in The American Journal of Cardiology, Paul Sparks (University of Melbourne) and colleagues explain that PV ectopy is critical for the initiation and maintenance of PAF. However, the effect of long-term fish oil supplementation on human PV electrophysiology remains unknown.

To investigate, the team recruited 36 patients with PAF, aged 18 to 75 years, who were undergoing PV isolation. At least 1 month before ablation (mean 40 days), the participants were randomly assigned to receive active therapy with fish oil (6 g/day; fish oil group) or no therapy (control group).

Pulmonary venous and left atrial ERPs, PV conduction, and susceptibility to AF initiated within PVs were assessed in all patients after the supplementation period.

The researchers report that serum omega-3 polyunsaturated fatty acid levels were at least two fold higher in the fish oil group compared with controls on the day of testing.

The fish oil group had significantly longer pulmonary venous and left atrial ERPs compared with controls. Furthermore, there was less dispersion of refractoriness in the PVs of fish oil patients compared with controls.

The authors say that, as a consequence of shorter pulmonary venous ERPs, there was a significantly lower incidence of AF initiated from PVs during ERP testing in the fish oil group (33.3%) compared with controls (70.6%).

In addition, the fish oil group exhibited a significantly longer mean first induced AF cycle length (209 vs 133 ms, respectively), shortest AF cycle length (164 vs 100 ms), and longest AF cycle length (223 vs 170 ms) in PVs than controls.

The researchers suggest that the shorter ERPs of the controls "exposed them to shorter coupling intervals during testing, resulting in higher incidence of PV-initiated AF. As a direct consequence of higher PV refractoriness, patients on fish oil had decreased susceptibility to PV-initiated AF and longer cycle length AF in PVs," they say.

Of note, "it is unclear if the described electrical properties in patients taking fish oil are due to suppression of arrhythmia frequency and subsequent reverse electrical remodeling of PVs in the preceding days or weeks before testing or an effect of incorporated fish oil on pulmonary venous cellular membranes," conclude Sparks et al.

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Nikki Withers

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