[Technic of tetrapolar rheography for determining cardiac stroke volume in patients with mitral stenosis in the late stages].

On the basis of model and clinical investigations using differential rheograms , a conclusion was drawn that in measuring the curve of Ad amplitude from the isoelectric line, the cardiac stroke volume ( SHV ) averaging 30-80 ml as determined by the method of tetrapolar chest rheography and calculated by the formula of Kubi cek et al. (formula see text) was in full agreement with the SHV determined by Fick's method for the same heart rate. When calculated by formula (formula see text) or (formula see text) which used (formula see text) or delta Z found by extrapolating the rheographic curve according to the method of A. A. Kedrov or N. R. Paleev , the SHV proved to be lower and, therefore, in order to obtain more accurate values of the SHV , corrective coefficient K should be introduced into these formulae. The value of K is determined by an inverse dependence between the volumetric rate of the cardiac output and the resilient-viscous properties of vessels, and it varies with different heart rates.