EFFECTS OF DIETARY SUPPLEMENTATION WITH ALPHA-TOCOPHEROL ON MYOCARDIAL INFARCT SIZE AND VENTRICULAR ARRHYTHMIAS IN A DOG-MODEL OF ISCHEMIA-REPERFUSION

[摘要] 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 supple mented 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 mu mol/liter, mean +/- SEM) compared with dogs that did not (2.1 +/- 0.2 mu mol/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 how 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.

[发布日期] 1994-11-15