The constant and regular correlates of emotional stress states are ethological and vegetative reactions that serve regulatoryadaptive functions. The cardiovascular system plays a key role in the body’s adaptation to emotional and stressful challenges. The study aimed to study heart rate variability to identify indicators that have prognostic value regarding the occurrence of cardiac disorders in the form of arrhythmias. Using electrocardiography and interval cardiometry, the occurrence of heart rhythm disorders was investigated, depending on the duration of stress exposure and the individual typological characteristics of animals in the process of forming an emotional and stressful state. The article presents the results of studies of the emotional stress state under the conditions of the “afferent excitation conflict” model in 70 sexually mature male Wistar rats weighing 200-250 g and taking into account the basic principles of bioethics. It has been established that a prognostic factor unfavorable for the occurrence of heart rhythm disturbances is the absence of discrepancy in changes in the statistical characteristics of the heart rhythm after shortterm stress exposure in combination with the predominance of sympathetic extracardial regulatory influences. It has been shown that animals with a predominance of parasympathetic regulatory influences on heart rate and a decrease in centralization of control (decrease in the tension index) during the formation of neurogenic stress were more resistant to heart rhythm disturbances.