Acute myocardial infarction (AMI) is a leading cause of mortality and morbidity worldwide, especially in developed countries. The most serious problem after myocardial infarction is reperfusion injury that is manifest as functional impairment, arrhythmia, and accelerated progression of cell death in certain critically injured myocytes. Subsequently the infarcted myocardium develops features of necrosis and reactive inflammation. To reduce lethal reperfusion injury in patient with AMI we use antioxidants, anti‐inflammatory agents, adenosine, opioids, metabolic modulators (glucose, insulin, and potassium, nicorandil and agents which reduce intracellular Ca2+ overload and inhibit Na+‐H+ exchange). In our study a novel compound (9) 1‐(1h‐indol‐4‐yloxy)‐3‐{[2‐(2‐methoxyphenoxy) ethyl]amino}propan‐2‐ol and its enantiomers were examined in arrhythmia associated with coronary artery occlusion and reperfusion rat model. For test compounds were also determined antioxidant properties using MDA and FRAP tests. In summary, the tested compounds, especially the S enantiomer has a strong antiarrhythmic activity in a model of occlusion and reperfusion of the left coronary artery which is probably related to their adrenolytic action. In contrast, to carvedilol none of the test compound reduced the lipid peroxidation but increase ferric reducing antioxidant power. In the antioxidant effect, there was no difference between the optical forms of compound 9. This article is protected by copyright. All rights reserved.