title: Effects of antioxidant vitamins C and E on signal-averaged electrocardiogram in acute myocardial infarction.
abstract: Experimental studies indicate that oxygen-free radicals contribute to ischemic myocardial damage and affect electric properties of cellular membranes. We hypothesize that an association exists between an oxygen-free radical-induced component of myocardial ischemic injury and altered electric function that underlies the genesis of ventricular late potentials in the course of myocardial infarction. If so, antioxidant vitamins C and E may prevent alterations in the signal-averaged electrocardiogram (SAECG). To test this hypothesis, we investigated the effect of supplementation with vitamins C and E on the indices of the SAECG in patients with acute myocardial infarction (AMI). Sixty-one patients with AMI were randomized to receive conventional treatment and vitamins C and E, each 600 mg/day, orally for 14 days (supplemented group, n = 33) or conventional treatment only (control group, n = 28). SAECG was recorded on days 1 or 2 and between days 9 and 13 (mean 10). Serum ascorbic acid, tocopherol, plasma lipid peroxides, and oxygen-free radical production by isolated leukocytes were measured on days 1 or 2 and between days 12 and 14. In the control group, SAECG showed an increase in mean QRS and low-amplitude ( < 40 microV) signal durations, from 99 +/- 10 to 111 +/- 13 ms (p < 0.001) and from 31 +/- 8 to 38 +/- 10 ms (p < 0.001), respectively, and a decrease in the root-mean-square voltage of the last 40 ms of the QRS complex, from 36 +/- 25 to 21 +/- 11 microV (p < 0.002). In vitamin-supplemented patients, all these indices remained unchanged. Oxygen-free radical production by isolated leukocytes was decreased compared with that in controls (p < 0.02). Supplementation was confirmed by elevation of serum ascorbic acid and tocopherol. Results support the hypothesis that in patients with AMI, oxygen-free radical-induced cellular damage contributes to alterations in electric function of the heart as seen on the SAECG.
authors.affiliation: Department of Cardiology, Postgraduate Medical School, Grochowski Hospital, Warsaw, Poland.
authors.forename: T
authors.initials: T
authors.lastname: Chamiec
authors.forename: K
authors.initials: K
authors.lastname: Herbaczyńska-Cedro
authors.forename: L
authors.initials: L
authors.lastname: Ceremuzyński
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000097:blood / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D004562:Electrocardiography; D005260:Female; D005609:Free Radicals; D006801:Humans; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism; D008054:Lipid Peroxides / Q000097:blood; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012815:Signal Processing, Computer-Assisted; D014810:Vitamin E / Q000097:blood / Q000627:therapeutic use*
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D008054:Lipid Peroxides; D017382:Reactive Oxygen Species; D014810:Vitamin E; D001205:Ascorbic Acid