[A simple kinetic model of myocardium contraction: calcium-mechanics coupling].

A kinetic model of cardiac muscle contraction is suggested. It is based on our earlier simplified model of the kinetics of the actin-myosin interaction. We examined the kinetics of formation of calcium-troponin complexes that open the binding sites-on actin for myosin heads. The model also takes into account the cooperativity of this process and the influence of myosin heads on it. It was shown that with proper choice of its parameters the model appropriately describes the dependence of myocardium activation.on sarcomeres length that underlies the Frank-Starling law of the heart. The model fits both steady state experiments on myocardial specimens with permeable membrane and twitch contractions of intact cardiac muscle. It also describes well the myocardium load-dependent relaxation.