Reduced incidence of vagally induced atrial fibrillation and expression levels of connexins by n-3 polyunsaturated fatty acids in dogs.
OBJECTIVE
This open-label canine study assessed whether n-3 polyunsaturated fatty acids (PUFAs) prevent vagally induced atrial fibrillation (AF) and influence atrial tissue expression levels of connexins (CXs).


BACKGROUND
n-3 polyunsaturated fatty acids in fish oils protect against sudden cardiac death and reduce postoperative AF. Changes in spatial organization of gap junctions or cellular CX levels have been linked to arrhythmogenesis.


METHODS
Vagally induced AF was studied. Eight dogs were given fish oil daily for 14 days. Eight control dogs had reproducibly induced AF and were re-evaluated after intravenous administration of fish oil. Atrial fibrillation was compared, and n-3 PUFA, CX40, and CX43 protein levels were assessed in atrial biopsies.


RESULTS
Atrial tissue n-3 PUFA levels increased in oral treatment dogs (5.78 +/- 0.71% vs. 2.49 +/- 0.46% in control animals, p < 0.001). No difference was observed for atrial refractory periods or hemodynamic or electrocardiographic parameters. Incidence of AF in oral treatment dogs decreased 79% with the extra stimulus technique (10.5% vs. 48.9%, p = 0.003) and 42% with burst induction (22.5% vs. 38.8%, p = 0.038). Both CX40 and CX43 levels were lower in oral treatment dogs (60% [p = 0.019] and 42% [p = 0.038] lower, respectively); protection against AF was mostly related to reduced CX40 expression levels (p = 0.02). In dogs that were given intravenous n-3 PUFAs, AF inducibility by the extra stimulus technique was reduced from 75.0% to 28.6% (p = 0.002).


CONCLUSIONS
Oral treatment with fish oils increased atrial n-3 PUFA levels and reduced vulnerability to induction of AF in this dog model. Modulation of cardiac CX by n-3 PUFAs probably contributes to the antiarrhythmic effects of fish oils.
Sarrazin
Jean-Francois
JF
Institut Universitaire de Cardiologie et Pneumologie, Quebec, Canada.
Comeau
Genevieve
G
Daleau
Pascal
P
Kingma
John
J
Plante
Isabelle
I
Fournier
Dominique
D
Molin
Franck
F
D000818:Animals; D001281:Atrial Fibrillation / Q000517:prevention & control*; D015153:Blotting, Western; D002304:Cardiac Pacing, Artificial; D018031:Connexin 43 / Q000378:metabolism*; D017630:Connexins / Q000378:metabolism*; D004195:Disease Models, Animal; D004285:Dogs; D022062:Electrophysiologic Techniques, Cardiac; D015525:Fatty Acids, Omega-3 / Q000032:analysis / Q000494:pharmacology* / Q000627:therapeutic use*; D005260:Female; D006325:Heart Atria / Q000187:drug effects* / Q000378:metabolism*; D007262:Infusions, Intravenous; D008297:Male; D009206:Myocardium / Q000378:metabolism; D014630:Vagus Nerve; D000097003:Gap Junction alpha-5 Protein
D018031:Connexin 43; D017630:Connexins; D015525:Fatty Acids, Omega-3; D000097003:Gap Junction alpha-5 Protein