[The mechanism of setting the common rhythm of the pacemaker pair in the sinoatrial node]

Principal physiological hypotheses concerning the setting of united rhythm in the heart sinoatrial node (SAN) are considered. A mathematical model of SAN is proposed which takes into account properties of individual elementary pacemakers and their interaction. Assuming paired interaction of the pacemakers there are revealed the main P.D. parameters, affecting the setting of the united rhythm. Quantitative expressions are obtained for the united rhythm period, delay and propagation velocity of the excitation. The calculated data are compared with the experimental ones. The hypothesis concerning the setting of the united rhythm as a result of the interaction of SAN pacemakers is confirmed.