Antioxidants decrease reperfusion induced arrhythmias in myocardial infarction with ST-elevation

In myocardial infarctions with ST-segment elevation, ischemia followed by reperfusion ( IR) leads to arrhythmia, myocardial stunning and endothelial dysfunction injury by reactive oxygen species ( ROS). To determine the impact of ROS, we examined the effect of antioxidant vitamins on biochemical changes and arrhythmias induced by reperfusion before and after therapeutic thrombolysis ( Actilyse ((R))). As compared with those receiving placebo, in individuals who received antioxidants, there was a significant decrease in premature ventricular beats ( 100% vs 38%), atrial fibrillation ( 44% vs 6%), ventricular tachycardia ( 31% vs 0%), first- degree atrial- ventricular block ( 44% vs 6%), plasma malondialdehyde at the first hour after initiation of thrombolysis ( 1.07 +/- 0.10 vs 0.53 +/- 0.10 nmols plasma malondialdehyde/mg protein) and circulating neutrophils after 24 hr after reperfusion. The antioxidant capacity of plasma was increased from 1.89 +/- 0.15 to 3.00 +/- 0.31 units/ mg protein and paraoxonase-1 rose from 0.77 +/- 0.08 to 1.27 +/- 0.11 nmol/ min/ mg protein. These findings suggest that antioxidants might be useful as adjuvants in controlling reperfusion induced arrhythmias following therapeutic alteplase thrombolysis.