Investigation of the synchronization of the sinoatrial node upon stimulation from atria

The excitation of the sinoatrial node from frog heart atria has been experimentally investigated. Potentials were measured by means of microelectrodes introduced in pacemaker cells of the sinoatrial node. It has been found that atria can modulate the rhythm of the sinoatrial node due to electric and electromechanical actions, among which the electromechanical action is more important. Specific transient processes accompanying the establishment of the stationary rhythm have been studied. A mathematical model of the transient processes of achieving the rhythm of the sinoatrial node is proposed on the basis of Diophantine methods. The calculations performed using the mathematical model satisfactorily agree with the experimental results. The stabilizing role of atria in forming the rhythm of the sinoatrial node is revealed.