Theoretical Aspects of Measuring Input Resistance in Syncytial Tissue by Means of Double-Barreled Electrode

Abstract

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).