Abstract 2620: n-3 Polyunsaturated Fatty Acid Prophylaxis Reduces Vulnerability to Atrial Fibrillation in a Dog Model of Cardiomyopathy
Clinical studies demonstrate that omega-3 polyunsaturated fatty acids (PUFAs) reduce major cardiovascular events. We have shown that PUFAs prevent atrial fibrillation (AF) inducibility in a novel canine model by reducing atrial extracellular matrix deposition and inhibiting cellular hypertrophy. We hypothesized that PUFAs would be most effective at reducing vulnerability to AF in this model when given prophylactically as opposed to post cardiac injury.
Methods: Fifty-three dogs were randomized into 5 groups. Two groups underwent simultaneous atrial and ventricular pacing (SAVP) at 220 bpm for 7 or 14 days to induce susceptibility to AF. Two other groups were paced for 14 days and supplemented with oral PUFAs for either 21 days (starting 7 days before pacing) or 7 days (starting 7 days after the start of pacing). The final group was an unpaced, unsupplemented control group.
Results: Administered PUFAs were retained in plasma and atrial tissue (Plasma: 5.3±0.9% vs. 5.2±0.7% vs. 3.3±0.3%; Tissue: 3.4±0.4% vs. 3.2±0.3 vs. 2.5±0.3%; % PUFAs in total phospholipids after 21 days PUFAs vs. 7 days PUFAs vs. 0 days PUFAs respectively; p<0.01 for both plasma and tissue comparisons). AF incident inducibility increased significantly with increasing pacing duration as did persistent AF inducibility (see Fig 1⇓). Prophylactic PUFA supplementation decreased AF incidence and persistence more than PUFAs started after the onset of pacing.
Conclusion: In a model of atrial cardiomyopathy, despite virtually identical PUFA levels in tissue, only prophylactic PUFA treatment significantly attenuates AF inducibility.