Dietary n-3 fatty acids promote arrhythmias during acute regional myocardial ischemia in isolated pig hearts.
OBJECTIVE
Dietary supplementation with fish oil-derived n-3 fatty acids reduces mortality in patients with myocardial infarction, but may have adverse effects in angina patients. The underlying electrophysiologic mechanisms are poorly understood. We studied the arrhythmias and the electrophysiologic changes during regional ischemia in hearts from pigs fed a diet rich in fish oil.


METHODS
Pigs received diets rich in fish oil, in sunflower oil, or a control diet for 8 weeks. Hearts were isolated and perfused. Ischemia was created by occluding the left anterior descending artery. Diastolic stimulation threshold, refractory period, conduction velocity, activation recovery intervals and the maximum downstroke velocity of 176 electrograms were measured in the ischemic zone. Spontaneous arrhythmias during 75 min of regional ischemia were counted.


RESULTS
More episodes of spontaneous ischemia-induced sustained ventricular tachycardia and ventricular fibrillation occurred in the fish oil and sunflower oil group than in the control group. More inexcitable myocardium was present in the ischemic zone in the group fed fish oil or sunflower oil than in the control group after 20 min of ischemia. After 40 min of ischemia, more block occurred in the control group than in the other groups. The downstroke velocity of the electrograms in the ischemic border zone was lower in the fish oil group and sunflower oil group than in the control after 20 min.


CONCLUSIONS
A diet rich in fish oil results in proarrhythmia compared to a control diet during regional ischemia in pigs. Myocardial excitability is reduced in the fish oil and sunflower oil group during the early phase of arrhythmogenesis. In the late phase of arrhythmogenesis, excitability is more reduced in the control group than in the fish oil and sunflower oil group.
Coronel
Ruben
R
Department of Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands. r.coronel@amc.uva.nl
Wilms-Schopman
Francien J G
FJ
Den Ruijter
Hester M
HM
Belterman
Charly N
CN
Schumacher
Cees A
CA
Opthof
Tobias
T
Hovenier
Robert
R
Lemmens
Arnoldina G
AG
Terpstra
Antonius H M
AH
Katan
Martijn B
MB
Zock
Peter
P
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000503:physiopathology; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000032:analysis / Q000097:blood; D015118:Eicosapentaenoic Acid / Q000032:analysis / Q000097:blood; D004562:Electrocardiography; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D006321:Heart / Q000503:physiopathology; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism / Q000503:physiopathology; D010477:Perfusion; D010938:Plant Oils / Q000008:administration & dosage; D000074242:Sunflower Oil; D013552:Swine
D015525:Fatty Acids, Omega-3; D010938:Plant Oils; D000074242:Sunflower Oil; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid