The valve of pulmonary artery is of three shutters : back ( left ), front and right . With scan at M – mode of parasternal position by the long axis , as a rule , only the rear ( left ) leaf is visualized . Front and right flap rarely Visualize are , so as located at the corner to Ultrasonic th beam . AT moving the rear flap valve pulmonary artery is isolated next phase .Evaluation function of the ventricles , in features Pancreas , is one of most important tasks of echocardiography . Dysfunction of the left ventricle is a significant prognostic factor with any disease of the heart . Identification of LV dysfunction often leads to change medication therapy and at whole patient management tactics .
Possible errors in the identification of systolic dysfunction of the left ventricle
Linear dimensions LV measured from the endocardium of the IUS to endocardium of the posterior wall of the left ventricle . Mistakes are possible ki at measurement of hypertrophic papillary muscle or with calcification of the mitral ring , which is erroneously possible to accept beyond the posterior wall of the left ventricle .
For more accurate measurement should be taken into account , that of of these structures at systole thickens only the back wall of the left ventricle . With violation of the MZhP kinetics ( for example , blockade of the left leg of the bundle of His ) measurement of the shortening fraction becomes difficult . Required Remember , that the range of normal values of course diastolic and of course – systolic size depends on many factors , including age , gender , height and physique . Systolic dysfunction of the left ventricle , as a rule , combined with an increase in the linear dimensions of the LV . but at a number of cases , for example when a large area of akinesia after suffering a myocardial infarction , a violation of systolic function may be observed , despite on normal dimensions LV . An experienced researcher can often visually assess LV systolic function. of parasternal positionby long axis even before carrying out measurements . However, such a rough estimate not allows you to serially estimate volumes and the function of the left ventricle .
With assessment results serial measurements whether linear and volume indicators of the left ventricle , as well as fractions shortening and fraction of ejection is necessary to take into account mezhissledovatelskuyu and internal research variability of measurements . The main causes of variability is the choice frames for of measure and difficulties atdefining the border of the endocardium . With the calculation of the volume indicators of the left ventricle using certain geometric models forms LV . With diseases of the heart , in particular with violations of local contractility , use of data models reducible dit to significant errors . After LV acute myocardial infarction loses its normal ellipsoidal shape andbecomes spherical . The process received the name of post-infarction remodeling .
With assessment of systolic function of the left ventricle should take into account the possible effects of drug treatment and conditions of pre – and afterload . Volume overload as well as antiarrhythmic drugs with negative inotropic properties can reduce systolic LV function .
With presence of mitral insufficiency fraction ejection may be normal , although on decrease in contractile LV function . This is due with lower LP resistance at comparing with aorta . In contrast , with aortic stenosis , a low ejection fraction value can be obtained. despite on normal LV contractility . This is due with increased resistance , is overcome by direct LV at systole . So manner , after surgical correction of MR fraction ejection decreases , and after -compensation tion aortic stenosis fraction emission increases .
Cardiac output calculation by peak aortic blood flow rate incorrect at AR conditions or stenosis at connections with increase the speed of the aortic blood flow . Possible errors when measurements Diamé tra aortic rings significantly distort values cardiac ejection , so as diameter when calculating is being built at square .