ArticleOrlov RS, Krol' TM, Poliak SB.
Fiziol Zh SSSR Im I M Sechenova. 1977 Jun;63(6):872-80.
Chrono-ionotropic interrelationships were studied in isolated strips of the myocardium of poikilothermous animals (frogs and fishes) in conditions of either stationary or transitional regimens of stimulation. In the stationary regimen, the rhythm-strength relation is simple and corresponds to a parabolic curve. While changing the lesser frequency of stimulation for greater one, both the positive and negative transitional abbreviating stirs were observed, in contrast to literature references. The phenomena of positive and negative transitional stairs were concluded to be unrelated to species while being a general biological form of the myocardium response to change of the stimulation rhythm.