in article the algorithm of a posteriori calculation of heart rate on record EX. The algorithm produces the allocation of QRS complex for R-teeth, the classification of complexes into two types: normal and artifact complexes. It is proposed to classify the analysis of contours and measurement of interference at the frequency of 50 Hz. This classification can significantly improve the measurement accuracy of the instantaneous heart rate compared to the moving average

Keywords: frequency of cardiac abbreviations, RR interval, QRS complex, Holter monitoring, selection of artifacts of the FORMER, the algorithm for calculating heart rate, contour, RR–interferometry