title: Lack of significant effects of superoxide dismutase and catalase on development of reperfusion arrhythmias.
abstract: It has been reported that agents having the ability to scavenge oxygen-derived free radicals reduce the severity of ventricular arrhythmias that occur after brief coronary occlusion and reperfusion. Superoxide dismutase plus catalase (SOD + CAT) or placebo was administered in a blinded randomized fashion prior to coronary occlusion in rats (n = 25 each group) undergoing a 5-min left coronary occlusion followed by 15 min of reperfusion. During reperfusion, ventricular tachycardia (VT) developed in 96% of animals in both groups. Reperfusion ventricular fibrillation (VF) developed in 60% of the placebo group vs 56% in the SOD + CAT group (p = 1.0). Irreversible VF occurred in 40% of the placebo group vs 20% in the SOD + CAT group (p = 0.22). Atrioventricular block occurred in 12% of placebo and 4% of SOD + CAT animals (p = 0.61). There were no significant difference between groups in duration of VT (85 +/- 15 s (mean +/- SEM) placebo vs 81 +/- 14 s SOD + CAT, p = 0.81), total duration of VT plus VF (391 +/- 76 s placebo vs 256 +/- 64 SOD + CAT, p = 0.45) or numbers of single ventricular ectopic beats (65 +/- 15 placebo vs 97 +/- 18 SOD + CAT, p = 0.18). Heart rate at reperfusion was slightly higher in control than SOD + CAT animals (340 +/- 33 vs 319 +/- 32, p = 0.02). Risk zone size, determined by Monastral blue injection, was equal in both groups (34 +/- 2% of ventricular mass). The occurrence of reperfusion VF in this model could not be predicted by heart rate at reperfusion (331 +/- 33 VF animlas vs 328 +/- 36 no VF, p = 0.77), or by risk zone size (34 +/- 2%, VF and no VF groups).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Heart Institute, Hospital of the Good Samaritan, Los Angeles, California.
authors.forename: J M
authors.initials: JM
authors.lastname: Hagar
authors.forename: S L
authors.initials: SL
authors.lastname: Hale
authors.forename: J P
authors.initials: JP
authors.lastname: Ilvento
authors.forename: R A
authors.initials: RA
authors.lastname: Kloner
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects; D002374:Catalase / Q000494:pharmacology*; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D015425:Myocardial Reperfusion; D051381:Rats; D011919:Rats, Inbred Strains; D013482:Superoxide Dismutase / Q000494:pharmacology*
chemical_list: D000889:Anti-Arrhythmia Agents; D002374:Catalase; D013482:Superoxide Dismutase