Coronary Heart Disease
Effects of dietary supplementation with alpha-tocopherol on myocardial
infarct size and ventricular arrhythmias.
Sebbag L; Forrat R; Canet E; Renaud S; Delaye J; de Lorgeril M
Journal of the American College of Cardiology 1994 Nov 15;24(6):1580-5
OBJECTIVES. We investigated whether dietary supplementation with the
antioxidant vitamin alpha-tocopherol (500 mg daily) might reduce lethal
ventricular arrhythmias and infarct size. BACKGROUND. Previous studies
suggested that dietary supplementation with alpha-tocopherol may be associated
with a reduced risk of ischemic heart disease. However, the mechanism
of this protection remains unknown. METHODS. Beagle dogs were randomized
to either a supplemented or a control group. Because of the low mortality
rate in the supplemented group, five dogs were added to the control group.
After 2 months, dogs were anesthetized and underwent a 2-h coronary artery
occlusion and 6-h reperfusion. Plasma vitamin E, retinol and malondialdehyde
concentrations were assessed in all dogs. RESULTS. Fourteen dogs (11 of
25 control vs. 3 of 19 supplemented dogs, p < 0.05) developed ventricular
fibrillation during either ischemia or reperfusion. Malondialdehyde concentrations
were higher in dogs that subsequently developed arrhythmias (2.7 +/- 0.2
mumol/liter, mean +/- SEM) compared with dogs that did not (2.1 +/- 0.2
mumol/liter, p = 0.03). Among survivors with significant ischemia, infarct
size was larger in supplemented (n = 12, 58.5 +/- 3.3% of area at risk)
than in control (n = 11, 41.9 +/- 6.5%, p < 0.04) dogs. In addition,
for a given collateral flow, supplemented dogs (n = 16) developed larger
infarct size than control dogs (n = 15, p < 0.001, analysis of covariance).
CONCLUSIONS. The data suggest that dietary alpha-tocopherol supplementation
prevented lethal ventricular arrhythmias associated with ischemia and
reperfusion. However, its influence on infarct size and long-term prognosis
warrants further investigation.