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Biomedical subjects

M P Sakharov

Publications and source records attributed to M P Sakharov.

11 recordsLinked to original sources
PubMed1992

[Echocardiographic assessment of cardiac pump function using afterloading characteristics].

Seventy five patients and twenty healthy individuals were investigated by using cardiac ultrasound technique, followed by mathematical simulation of changes in left ventricular pressure during contraction. The findings show that the afterload characteristics based on a wealth of evidence for cardiac and left ventricular performance, unlike the conventional central hemodynamic parameters and cardiac phasic indices, enable the occult circulatory disorders to be revealed and the cardiac compliance with the arterial system to be assessed.

Echocardiography↗
PubMed1987

[Bicomponent analysis of the contractile capacity of the heart in ischemic lesions of the myocardium (experimento-clinical study)].

A study was made of cardiac pumping capacity in animals with local myocardial ischemia (9 experiments on cats), in 25 healthy persons and 21 patients suffering from coronary heart disease with stage I-IIA circulatory insufficiency using afterload characteristics (ALC). The latter reflected correlation between left ventricular pressure and aortic blood flow in constant blood filling and in a given inotropic heart condition. For combined assessment of ALC one should know its two parameters: power (maximum pressure in the zero blood flow) and rate (maximum blood flow rate in zero antipressure). It was shown that early stages of cardiac insufficiency were characterized both under experimental and clinical conditions by change in the inclination angle of an afterload curve and a shift of a working point on it to the right.

Animals↗
PubMed1983

Evaluation of the heart pump function by afterload intracardiac pressure and blood flow measurements in cats.

In experiments carried out on cats and by using a mathematical model the authors studied afterload characteristics of the left ventricle of normal and hypertrophied heart. They found that afterload characteristics, expressed by a relationship between left ventricular systolic pressure and the aortic blood flow rate, have both in a normal as well as in a hypertrophied heart a nearly linear character, do not depend on the elastic properties of the aorta, and can be described by two parameters: the force parameter--i.e. maximum pressure at zero flow (Pm), and the rate parameter--i.e. the maximum flow value at zero pressure (Qm). Afterload characteristics change at inotropic influences: positive inotropic effects shift the characteristics upward and rightward, negative inotropic action shifts them downward and leftward. In moderate hypertrophy, Pm and Qm increase, with the increase in Qm being greater. The parameters of afterload characteristics can be used as pump function indexes characterizing the heart's ability to cope with the load in the outflow tract.

Animals↗
PubMed1982

[Effect of inotropic factors in the postload characteristics of the heart].

It was shown in acute experiments on cats that the post-exercise characteristics of the left ventricle plotted as a dependence between the magnitudes of the maximal blood flow velocity and systolic intraventricular pressure in health and inotropic exposures are close to the linear ones. Adrenaline shifts the post-exercise characteristics upward and to the right, increasing both the maximal magnitude of the blood flow velocity at a zero pressure (velocity component) and the maximal magnitude of the pressure at a zero blood flow (force component), the latter rising to a greater extent. Calcium chloride and obsidan cause a parallel shift of the post-exercise characteristics: the force and velocity components diminish upon obsidan administration, while with CaCl2 they increase.

Animals↗
PubMed1981

[Experimental quantitative evaluation of the cardiac pump in function].

Experimental technique has been developed that makes it possible to change left ventricular after exercise on a wide scale during one beat at an intact circulation. The relationship between the maximal blood flow rate and left ventricular systolic pressure at permanently filled ventricle and inotropic state has been shown close to linear. This relationship (exercise characteristics) can be described by two parameters: maximal systolic blood pressure at blood flow and maximal blood flow ab zero peripheral resistance, and can be used for the assessment of the cardiac pump function.

Animals↗
PubMed1980

[2 components of ventricular contractility and their determination based on a noninvasive method].

It is suggested that a force component and a rate component should be distinguished for elaborating the quantitative values of the contractility of the heart ventricle. In experiments the first component is determined as the maximum pressure in the ventricle during isovolumic contraction, and the second component, as the maximum value of the blood flow in the ejection phase at zero afterload. Analysis of the data found in the literature and the results of the authors' experiments provides evidence that the force and rate components differ in their dependence on the hemodynamic conditions. A noninvasive method for determining the contractility components is suggested. Analysis of the clinical data and the literature confirms that the force and rate components change in a different manner in various types of pathological conditions.

Animals↗