[The effect of asynchronous contraction of the myocardium on its mechanical function].
The effect of asynchronous excitation of adjacent portions of intact myocardium was simulated in two parallel connected papillary muscles from the rabbit heart right ventricle. Mechanical characteristics (length-force, force-rate, final systolic length-specific time of relaxation) of each of the muscles were recorded in simultaneous and asynchronous contractions. The asynchronism was found to exert a positive inotropic effect in each of the muscles and a negative one in the duplex. The asynchronism decelerated the temporal course of relaxation both in separate muscles and in duplex. The asynchronism-related mechanochemical dissociation seems to be the crucial phenomenon underlying the whole cycle of the mechanical phenomena.
Bliakhman
F A
FA
Markhasin
V S
VS
Nafikov
Kh M
KhM
Izakov
V Ia
VIa
D000818:Animals; D001696:Biomechanical Phenomena; D004558:Electric Stimulation; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000502:physiology*; D010210:Papillary Muscles / Q000502:physiology; D011817:Rabbits; D013997:Time Factors
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