Abstract. The work investigates dangerous violations of the rhythm of cardiac activity-arrhythmias, the identification of which requires long-term monitoring of the patient. A processing algorithm that analyzes the time parameters of the ECG signal is proposed. The proposed algorithm is able to determine such rhythm disturbances as prolapse of ventricular complexes and various types of extrasystoles, as well as assess their main time parameters, which is extremely important for assessing the danger of disorders to human health.