Biomedical subjects

G G Zurabishvili

Publications and source records attributed to G G Zurabishvili.

5 recordsLinked to original sources

PubMedDate not supplied

[Different sensitivities of two mechanisms of excitation waves in heart tissue to anti-arrhythmia agents--blockers of fast sodium currents].

In experiments with rabbit ventricular tissue sensitivity of two kinds of spiral wave sources of excitation to fast sodium current inhibition was compared. These spiral wave sources were circulation in a ring around an obstacle and circulation in tissue without an obstacle (reverberator). It was observed that after application of antiarrhythmic drugs lidocaine or mexiletine there was a prominent growth of cycle length of reverberator during first few seconds of circulation and a little change of cycle length for the circus movement around obstacle. It is proposed that different sensitivity of both kinds of spiral wave sources to antiarrhythmic drugs can be used for their distinguishing in clinical practice.

Action Potentials↗

PubMedDate not supplied

[Mechanisms of differences of the cycle length of excitation spiral waves in atrial and ventricular tissues].

Ectopic spiral wave sources--reverberators--were produced in pieces of rabbit atrium and ventricle by an induction of a single properly timed premature impulse. It was found that the cycle length (T) of the ectopic source gradually increased immediately after its appearance in atrial and changed a little bit after its appearance in ventricular tissue. Relationship between changes of T and refractorines of the heart tissues was investigated. The model is proposed which explains these changes of T by the cycle length dependence on the value of fast inward sodium current.

Animals↗

PubMedDate not supplied

[Refractory properties of cardiac tissue at fast sodium current decrease. Comparison of atrium and ventricle].

Investigation of the membrane potential of Neurospora crassa mycelial cells was carried out by standard microelectrode technique. The resting potential is equal to--156 +/- 11 mV (negative inside the cell). The light of the spectrum blue-violet zone causes transient hyperpolarization of the cell membrane reaching --38 +/- 5 mV after 25 minutes of illumination.

Animals↗

PubMedDate not supplied

[Investigation of anomalous growth of heart refractoriness during tachycardia].

Action potential (AP) characteristics during anomalous growth of refractoriness (R) in rabbit atrium were investigated. Anomalous growth of R arises under the stimulation frequency more than 4-5 s-1. Anomalous R growth is accompanied by AP duration, amplitude and upstroke velocity decrease. These results are in a good agreement with the theoretical model (Pertsov et al., 1981), showing that anomalous R growth can be caused by a decrease of safety factor in propagation of the excitation wave.

Action Potentials↗

PubMedDate not supplied

[Refractoriness of cardiac tissue and mechanism of destruction of sources of spiral waves of excitation in the heart].

Ectopic spiral wave sources were produced in pieces of 15 X 15 mm of rabbit atrium by an induction of a single properly timed premature impulse. The cycle length of the ectopic source (T) gradually increased immediately after its appearance. It was shown that T growth is determined by the rise of refractoriness (R). It was found that besides the well known phenomenon of R shortening after f increase there is an opposite process of R lengthening at high driving rates (f > 4--5 sec--1). A hypothesis is advanced that the growth of refractoriness found is one of the death mechanisms of spiral wave ectopic sources in the heart.

Action Potentials↗