The aim of this work was to investigate the myocardial protection against ischemia/reperfusion using low level laser irradiation (LLLI). It has been shown that pulse pressure was higher in the period of post-ischemic reperfusion as compared with the control group. It provided a better restoration of myocardial contractility as well as increasing of coronary flow in the reperfusion period. The amount of ventricular rhythm disorder episodes decreased. These effects of laser application were registered in conditions of coronary flow reduction less than 50%. One of the suggested mechanisms of laser effect is an ATP-sensitive channel activation.