Аннотация:The mechanisms of functioning of the heart from the point of view of biophysics are described. The terms “(any) cardiac activity” or “(any) activity of the heart” should be used only for designation any aimless functioning of the heart. On the other hand, “the action of the heart” or “the cardiac action” should be comprehended as the functioning of the heart that is directed to maintenance of physiological homeostasis, which is the target function in this case. Obviously, the action of the heart can be put into effect only due to a quantity of control loops and guidance loops, - which all together organize one and indivisible cardiovascular system. Electrical phenomena, that accompany the functioning of the heart and can be recorded by electrocardiography, are nowise satisfying the target of the cardiovascular functioning, because they are but side effects of the autowave function of the heart.