Theoretical aspects of measuring input resistance in syncytial tissue by means of double-barreled electrode/Iejimo varzos matavimo sincitiniame audinyje dvikanaliu elektrodu teoriniai aspektai

The spread of electric excitation in the cardiac tissue is possible via local currents due to intercellular electric coupling. The measurements of input resistance were made, by using a double-barreled microelectrode technique, in order to evaluate the intercellular electric coupling between the myocardial cells in the trabecular area of the right atrium. Reliability of this technique was assessed by using a heptanol-induced blockade of intercellular electric communication. The baseline values of input resistance varied from 0.47 to 0.95 Mohms. Under the heptanol-induced decoupling, the propagation of excitation ceased and the input resistance value ranged from 1.17 to 2.59 MOhms, i.e. was smaller than the resistance of electrogenic membrane of one isolated atrial cell. A mathematical model of tissue input resistance was developed for analysis of experimental data. The results obtained can be explained by eventual injury of electrogenic membrane due to the double-barreled microelectrode penetration with ensuring effect upon the measurement accuracy largely dependent upon the resistance of damaged site. Ill. 4, bibl. 23 (in English; abstracts in English, Russian and Lithuanian). Elektrine sujaudinimo banga sirdies audinyje sklinda veikiant vietinems srovems per tarplastelinius kontaktus. Viena is pagrindiniu metodiku, ivertinanciu tarplastelinio elektrinio rysio dydi, yra iejimo varzos matavimas. Sios metodikos patikimumas buvo ivertintas matuojant iejimo varza triusio desiniajame priesirdyje. In vitro perfuzuojant sirdies gabaleli normaliu Tirodes tirpalu iejimo varzos dydziai buvo nuo 0,47 iki 0,95 megomo. Heptanolio poveikis uzblokuodavo sujaudinimo bangos sklidima, o iejimo varza buvo 1,17-2,56 megomo intervale, t. y. gerokai mazesne, negu vienos izoliuotos sirdies lasteles elektrogenines membranos varza. Eksperimentu duomenims analizuoti pateikiamas iejimo varzos matavimo matematinis modelis. Gauti rezultatai paaiskinami tuo, kad dvikanalis mikroelektrodas idurimo metu gali pazeisti lasteles elektrogenine membrana ir pazeidimo vietos varza gali tureti didele itaka matavimo tikslumui. Il. 4, bibl. 23 (anglu kalba; santraukos anglu, rusu ir lietuviu k.).