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Biomedical subjects

V I Krinskiĭ

Publications and source records attributed to V I Krinskiĭ.

At least 19 recordsLinked to original sources
PubMed1988

[The mechanism of the development of atrial tachyarrhythmia after stimulation of the vagus nerve].

Multielectrode mapping of stimulus propagation was used to investigate arrhythmias, developing in atrial preparations of frogs after vagal stimulation. Vagal stimulation produced attacks of tachycardia (one to several dozens extra-excitations) in 10 of 16 specimens. In such cases, mapping demonstrated re-entry of the excitation wave that appeared where the front of the next excitation wave from the sinus went along the border of temporarily-unexcitable area during the recovery of excitability in vagus-inhibited atrial areas. The emergence of re-entry was possible, because the excitation wave length (lambda), was shortened owing to reduced refraction and speed of conduction under vagal effect. After myocardial tissue got rid of vagal influence, lambda increased, after which re-entry was no longer possible, and arrhythmia discontinued.

Animals↗
PubMedDate not supplied

[A possibility of significant lowering the defibrillation current by determining the right time for application of a defibrillating pulse. A mathematical model].

The effect of defibrillating pulses on the functionally determined re-entries (leading circles) was studied by computer simulation. Arrhythmias caused by different numbers of leading circles (from 1 to 18) were investigated. The defibrillation threshold was found to vary 2-4-fold, depending on the time of application of a pulse. At small currents the defibrillation mechanism is principally different from the commonly known one and is linked to the movement of leading circles towards each other or towards the boundary of the excitable tissue.

Arrhythmias, Cardiac↗
PubMedDate not supplied

[Interaction of spiral and flat periodic autowaves in an active medium].

Interaction between the rotating wave and a periodic external source in the model of Fitz Hugh--Nagumo type was computed. When the periods of the external source are longer than the rotation period of the spiral wave (T greater than Ts) the external source does not affect the spiral wave. At T less than Ts autowave synchronization effects are observed. The oscillation period predetermined by the external source is set in all the points of the medium except the neighbourhood of the spiral wave. The dislocation (wavebreak) persists in the medium drifting slowly at the angle to the wave vector of the flat waves. After the external source is eliminated, the spiral wave with the original period restores from this dislocation. When the dislocation reaches the interface, it disappears. In this case after the switching off of the external source the resting state is established. A theory of the drift is proposed which connects the drift velocity with the nucleus size and the rotation period of spiral wave.

Heart Rate↗
PubMedDate not supplied

[Thermal activity of the isolated brain fragment].

The paper deals with thermovisional studies of thermal activity of hippocampus transplants placed in the eye anterior chamber of the rat. The method permits investigation into the dynamics of temperature field in the nervous tissue directly. In the transplants with synchronous spontaneous activity of large neuron groups there were found zones of high thermoactivity with mean amplitude 0.1 degree C, as well as thermopassive zones with temperature variations not above 0.03 degree C. Under certain conditions transfer of heat-up regions along the transplant surface, synchronous thermoactivation of single zones and chaotic regime of thermoactivation were observed. Causes of the observed effects are analysed. The method applied opens a new approach to the studies of space and time organization of the nervous tissue functioning in the course of its living activity.

Animals↗