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Updated: Sep 21, 2026

Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling
Published on: August 1, 2016
[Electrical activity of the heart cells and myocardial contractility during a change in extracellular sodium
Abstract:
The transmembrane potentials of the cells of the ventricle contractile myocardium of the rat and frog isolated hearts were studied as well as the strength of the ventricle contraction under the effect of a decrease (to 30 mM) or increase (up to 200 mM) in the sodium chloride concentration in the perfusate. The decrease led to a fibrillation of ventricles, 80-85% of contractile cells generating a high-frequency activity, 12-15% preserving the same AP and 3-5% having completely lost the excitability. The increase only affects the transmembrane potentials of ischemized myocardium. The decrease in the sodium concentration led to an augmentation of the contraction strength through the sodium-calcium exchange mechanism.
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