<p>The article presents the results of applying artificial intelligence algorithms to analyze multichannel electrograms of bioelectrical activity registered by microelectrode arrays from myocardium of isolated rat hearts under the influence of L-carnitine and adrenaline. Localization of activation times on electrograms was performed using a new neural network model based on the U-Net architecture adapted for one-dimensional signal segmentation. In the organism, L-carnitine is necessary for the oxidation of fatty acids. But the effects of its supplemental intake on the cardiovascular system are still poorly understood. A decrease in heart rate, myocardial excitation conduction velocity, intensity of coronary blood flow and physiologic cardiac response to adrenaline action ex vivo caused by L-carnitine were shown. The methodological approach, applying a neural network to analyze data from microelectrode arrays, tested in this research can be translated into clinical practice for electrograms obtained by electrophysiology study of human heart.</p> Graphical Abstract <p>The neural network model can automate the analysis of data from microelectrode arrays to study the frequency and spatiotemporal characteristics of myocardial bioelectrical activity</p> <p></p>