The necessity of developing an algorithm for preprocessing ultra-high resolution electrocardiosignals (UHR ECS) is substantiated. The causes of distortion of the useful signal are analyzed, two filtering methods have been developed for cardiac signals obtained from high-frequency (HF) and low-frequency (LF) channels for recording electrocardiograms (ECG). An algorithm for identifying the characteristic points of the ECS, denoted by the Latin letters P, Q, R, S, T, necessary for synchronization has been developed. The efficiency of the presented algorithm is estimated using the processing time of one signal record, as well as using the error matrix and calculating the Recall and Precision parameters.