en Cardiovascular Physiology/Pharmacology Cardiovascular Physiology/Pharmacology Experimental research article Experimental research article <div style="text-align: justify;">Introduction: Myocardial ischemia leads to electrical disturbance in the heart because of reactive oxygen specious. This study aimed to investigate the effects of gallic acid and cyclosporine A (CsA) together on electrocardiogram parameters in myocardium following ischemia - reperfusion (I/R) in isolated hearts.<br /> Methods: In this research, 50 Wistar rats weighing 250-300g were randomly divided into the 5 following groups: control, sham and gallic acid (7.5, 15 and 30mg/kg) in combination with CsA (0.2&mu;M). On the eleventh day, the hearts were removed and perfused with Krebs solution and ischemia was induced for 30min. Then, cyclosporine was administered for 10min at the 10 minutes before reperfusion and 10 minutes the beginning of reperfusion. By placing the electrode, the parameters of RR, PR, QT, TpeakTend, JT and QTcB interval, ST elevation, R, P, Q, S, T amplitude were recorded before ischemia and during reperfusion. <strong>Results:</strong> This study showed that RR, JT, interval, p duration, ST elevation and PVC numbers of control were increased during ischemia compared with sham and decreased using gallic acid (7.5, 15 and 30mg/kg) in combination with CsA. In addition, P, R, S, T amplitude during the ischemia were decreased in control compared with sham and increased with gallic acid (15mg/kg) in combination with CsA.<strong> Conclusion:</strong> In conclusion, the optimal combination of both drugs decreased arrhythmia occurrence while increased electrical velocity of conduction and wave amplitudes in isolated myocardium after ischemia reperfusion injury.</div> Gallic acid, Cyclosporine A, Ischemia reperfusion injury. 162 170 http://ppj.phypha.ir/browse.php?a_code=A-10-1324-1&slc_lang=en&sid=1 Najmeh Sadeghi 3200319475328460029228 3200319475328460029228 No Sirjan School of Medical Sciences , Sirjan, Iran Samira Saadatfard 3200319475328460029229 3200319475328460029229 No Research Center for non. Communicable Diseases, Jahrom University of Medical Sciences, Jahrom, Iran Mahin Dianat 3200319475328460029230 3200319475328460029230 No Department of Physiology, Faculty of Medicine, Ahvaz University of Medical Sciences, Ahvaz Iran Hassanali Abedi 3200319475328460029231 3200319475328460029231 No Department of Physiology, Faculty of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran Khatereh Dehghani dkh.dehghani@gmail.com 3200319475328460029232 3200319475328460029232 Yes Department of Cardiology, Faculty of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran