[Clinical advantages of echocardiography in evaluating the left ventricular function]

This communication reported the present understanding on clinical advantages of echocardiography in evaluating practically left ventricular function. To evaluate the global function of the left ventricle, Sarnoff's function curve is clinically applicable, although it is quite difficult to change the preload in most clinical situations. Instead of the plotted function curve, only one functioning point is commonly used for the evaluation, the address of which is determined by the parameters related to preload and cardiac output, respectively. Echocardiography has been the most acceptable method for the clinical evaluation of left ventricular function as the noninvasive nature. The left ventricular size, shape, and function are not independent, but interrelated parameters. In estimating left ventricular volume based on the M-mode echocardiographically measured short axis, several calculation methods have been proposed. Various parameters of left ventricular pump function, such as ejection fraction, percent fractional shortening rate, and mean velocity of circumferential fiber shortening are basically calculated using left ventricular dimensions. However, these calculations are valid only when the dimensions are determined appropriately in the presence of symmetric and uniform contractions of the left ventricle. All these are satisfied, then, ejection fraction and fractional shortening are the most practical parameters for the global function. In ischemic diseases, problems of regional left ventricular function and segmental wall motion analysis are particularly indispensable. The regional function should be differentiated from the global function. It is extremely difficult to display the entire left ventricle in one echocardiographic section, and a combination of the parasternal and apical views can provide an adequate segmental wall motion analysis.(ABSTRACT TRUNCATED AT 250 WORDS)