[Effect of changes in the concentrations of Na, K and Ca ions in the medium on rhythmo-inotropic relationships in pathologically altered myocardium].
The following criteria of the myocardial insufficiency were revealed on myocardial fragments of the human auricule tissue (auricula atrii) removed in correction of the valvular cardiac defects: 1) fall of the contraction amplitude in the rhythmic row even with the stimulation frequency of 1--3 Hz (normal mycadrium is characterized by increased contraction amplitude--positive Bowdwitch steps) 2) monophasic character of the frequency-force curve (in a normal myocardium the curve is three-phasic in shape); 3) the absence of positive or the appearance of negative inotropic effect in response to reduction of the external Na concentration or removal of K ions from the solution. The data obtained permit to suggest that disturbed Ca ion transport through the surface membrane and reduction of the capacity of the sarcoplasmic reticulum to sequestrate Ca ions underlay myocardial insufficiency of the cardiac cells of the affected heart.
D002118:Calcium / Q000494:pharmacology*; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D011188:Potassium / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology*
D012964:Sodium; D011188:Potassium; D002118:Calcium
Vliianie izmeneniĭ kontsentratsii ionov Na, K i Ca v srede na ritmo-inotropnye otnosheniia v patologicheski izmenennom miokarde.