[Changes in the myocardial contractility of the left ventricle and in the central hemodynamic indices during the onset and termination of a paroxysmal tachycardia attack].

Three types of myocardial contractility and central hemodynamic response were identified on the basis of myocardial function and heart rate during an attack of paroxysmal tachycardia. Heart rates of up to 180 beats per minute are not associated with any myocardial contractility disorders, and hemodynamic disturbances are controlled by elevated myocardial inotropism. Heart rates reaching 190 beats/min are associated with a suppression of myocardial relaxation, and the Frank-Starling mechanism is added to elevated inotropism to control the disturbance. Where the heart rate is above 200 beats per minute, both myocardial relaxation and contraction are suppressed; the Frank-Starling mechanism is responsible for the control here.