Echocardiographic evaluation of left ventricular size, shape and function--advantages and limitations of this method.

Both M-mode and two-dimensional echocardiographies are now available in most institutions and hospitals. Correct understanding of the characteristics of M-mode and two-dimensional echocardiography, such as time resolution, will lead us to a successful application of each of these two displays. Detection of changes in ventricular wall and visualization of segmental wall motion are the most unique abilities in echocardiography. These characteristics permit echocardiographic evaluation of left ventricular function. Left ventricular size, shape and function are not independent parameters, but are interrelated. Various parameters on left ventricular function are calculated from the dimensions of the left ventricle. However, these estimations are valid only when the dimensional determination is optimized and all the assumptions on the model of the left ventricle are satisfied. The simultaneous display system of M-mode and two dimensional echocardiograms on the same frame has been shown particularly useful for an optimization of the measurements. For ischemic heart disease, a knowledge of regional function of the left ventricle and the analysis of segment wall motion are indispensable. One of the major problems in evaluating the left ventricle using echocardiography is a limited acoustic window. A combination of standard parasternal approaches and other approaches is commonly required for obtaining an entire image of the left ventricle.