Abstract 1259: Polyunsaturated Fatty Acids Reduce Inducible Atrial Fibrillation in a New Canine Pacing Model
Polyunsaturated fatty acids (PUFA) may prevent atrial fibrillation (AF) after cardiac surgery, but their anti-arrhythmic effects in the atria have been little studied. We evaluated the effects of PUFA in a new canine model of inducible AF.
Methods and Results: Eighteen mongrel dogs (19 to 36 kg) were studied in 3 groups: 4 control (no pacing; CTRL) and 14 simultaneous atrio-ventricular pacing (SAVP) dogs (2 weeks at 220 bpm, atrio-ventricular delay 0 ms), randomly assigned to no PUFA treatment group (6 dogs) and PUFA treatment group (8 dogs). PUFA (Dose: EPA + DHA, 1g/day) were administered orally, beginning 1 week before the pacemaker was turned on until the end of the study; 3 weeks in total. Bipolar pacing leads were placed in the right ventricular apex and in the right atrial appendage and connected to a single-chamber pacemaker via a “Y connector”. At the terminal study, 5 bipolar electrodes were attached to the epicardium on both atria. Atrial effective refractory periods (AERP) and atrial conduction times (ACT) (defined as the mean interval between the stimulation at each pacing site and the unipolar electrogram at the other 4 sites) were measured at 200 ms cycle length (CL). Atrial burst pacing (10Hz, 10s) was applied at each site; % AF yield (% of attempts resulting in AF >1min), median AF duration per dog and % of dogs with at least one AF episode >10min were recorded. After two weeks of stimulation, both paced groups had similar atrial and ventricular dysfunction: left atrial emptying function was 13.6 ± 6.9% vs 18.3 ± 7.0% (p=NS) in no PUFA vs PUFA dogs, respectively, and the left ventricular shortening fraction was 23.8 ± 16.8% vs 26.3 ± 8.0% (p=NS) in no PUFA vs PUFA dogs, respectively. PUFA dogs had less AF inducibility compared to no PUFA and less AERP prolongation and ACT slowing than CTL dogs (table⇓).
Conclusion : PUFA can prevent atrial electrical remodelling and AF vulnerability in a new canine pacing model of atrial cardiomyopathy.