Several different methods enable the study peripheral microcirculation. Among them, non-invasive laser Doppler flowmetry (LDF) is routinely used to assess microvascular function by quantifying rapid changes in skin blood flow in response to a given pharmacological or mechanical stimulus [1]. Owing to its accessibility, peripheral microvascular function has been proposed as a diagnostic and prognostic marker in cardiovascular disease. Importantly, it has been shown that peripheral microvascular endothelial dysfunction correlates with endothelial function in coronary microvessels suggesting that endothelial dysfunction is a globalized pathological condition [2]. However, there is still a strong need in clinical practice to develop a tool which enables heart microcirculation in vivo assessment. Although, a direct assessment of the target microvascular bed such as coronary microcirculation is technically challenging. Cardiac surgery, especially coronary artery bypass grafting (CABG), may be associated with several cardiovascular complications, including ischemia or acute myocardial infarction, arrhythmias and hemodynamic instability. Therefore, the possibility of intra- and postoperative myocardial microvascular perfusion assessment is of major clinical importance. Various studies have indicated that LDF is able to detect the real-time oscillations in myocardial perfusion in different experimental setups [3]. Of note, there is relatively little data concerning myocardial microvascular measurements in humans.