Newer Aspects of Echocardiography

Abstract

The recent increase in interest in echocardiography is partially due to the feasibility of using this technic to evaluate left ventricular performance in a noninvasive manner. It has been demonstrated that one can obtain an internal dimension of the left ventricular cavity and that this dimension is closely related to the corresponding volumes in uniformly contracting ventricles. Thus in patients with valvular heart disease, congenital heart disease, or cardiomyopathy, echocardiography provides an excellent noninvasive means of estimating diastolic volume, systolic volume, stroke volume, ejection fraction, and mean rate of circumferential shortening. In patients with segmental left ventricular disease, such as with coronary artery disease, these dimensions may not be true reflectors of the corresponding volumes. In such ventricles one probably should use echocardiography to evaluate the motion of individual segments of the chamber. To evaluate overall left ventricular function, one could use the mitral valve echoes to estimate mitral valve flow and left ventricular diastolic pressure. Echocardiography also provides a method of measuring wall thickness of the posterior left ventricular wall and the interventricular septum. Many echocardiographic technics for the diagnosis of congenital heart disease have recently been described. Most of these technics obviously need further substantiation; however, the size of the list is impressive and makes one feel that even the more complicated forms of congenital heart disease may be unraveled with echocardiography. The use of a strip-chart recorder has greatly improved and broadened the echocardiographic examination. Besides making the examination technically easier, it provides a means of appreciating the interrelationship of many cardiac echoes. A critical problem facing echocardiographly is the maintenance of high-quality examinations. Unfortunately the examination is not easy, and it requires a well-trained, highly skilled individual. The acceptance of the technic by the clinician has produced a demand which exceeds the available manpower to do adequate echocardiography. As a result much of the echocardiography being done is totally inadequate. The technic is still new and relatively unproven, and it cannot tolerate much abuse by people not well trained. One possible safeguard to the maintenance of high-quality echocardiography is for clinicians to be familiar with what a good echocardiogram looks like. The difficulty with echocardiography is mainly in doing the examination. not necessarily in the interpretation. Thus if the technical quality can be maintained, there is no doubt that echocardiography will play an increasingly important role in clinical cardiology.