Long chain n-3 polyunsaturated fatty acids reduce atrial vulnerability in a novel canine pacing model

Aim Our objective was to assess the effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on atrial fibrillation (AF) vulnerability and atrial structure in a new model of atrial cardiomyopathy. Methods and results Dogs were studied in three groups: seven control dogs (UNPACED) and 24 dogs undergoing simultaneous atrioventricular pacing (for 2 weeks) assigned to placebo treatment (SAVP-PLACEBO, n = 12 dogs) or oral n-3 PUFAs (1 g/day) treatment (SAVP-PUFA, n = 12 dogs). SAVP-PUFA dogs had less AF inducibility (percentage of burst attempts leading to AF episodes: 5.5 +/- 7.4 vs. 20.4 +/- 14.2, P < 0.001) and maintenance [median AF duration: 601 s (377-1216) vs. 1598 s (1195-2400), P < 0.05] than SAVP-PLACEBO dogs. SAVP-PUFA dogs had significantly less local stowing of conduction and conduction heterogeneity than SAVP-PLACEBO dogs. SAVP-PUFA dogs had a significantly smaller increase in atrial matrix metalloproteinase-9 activity and in collagen type I and III messenger RNA expression (in arbitrary units) than SAVP-PLACEBO dogs (0.62 +/- 0.51 vs. 10.80 +/- 5.61, respectively for collagen I, P < 0.05; 1.66 +/- 0.48 vs. 5.24 +/- 1.16, respectively, for collagen III, P < 0.05). Conclusion n-3 PUFA supplementation can reduce AF vulnerability in a new canine pacing model of atrial cardiomyopathy. The mechanism may be related to attenuation of collagen turnover.