INTERACTION OF BRAIN AND INTRACARDIAC LEVELS OF RHYTHMOGENESIS HIERARCHICAL SYSTEM AT HEART RHYTHM FORMATION

A single-stage bilateral conduction blockade of the vagus nerves (functional denervation) by constant anodal current was carried out in 13 dogs which are under anesthesia and 3–5 days after operation in chronic experiments. In anesthetized animals, "functional denervation" led to acceleration of the heart rhythm from 102.4 ± 3.2 bmp to 123.8 ± 4.4 bmp. In chronic dogs "functional denervation" led to transient stoppage of the heart — a preautomatic pause with duration of 2.7 ± 0.2 sec. The heartbeats recommenced with the frequency of 89.0 ± 3.4 bmp versus an initial rhythm of 118 ± 1.5 bpm, i.e., a rhythm deceleration took place. We conclude that in a whole organism the heart rhythm pacemaker is determined by a brain level of the hierarchical system of rhythmogenesis, while the sinoatrial node plays the role of a latent pacemaker.