Quantitative Analysis of Wall Motion

Abstract

In resting conditions as well as during stress, regional wall motion is usually assessed by a qualitative and subjective analysis that, although the only suitable method for clinical purposes, represents the true “Achilles’ heel” of echocardiography in ischemic heart disease. It is therefore understandable that great efforts have been made to give a sounder (i.e., quantitative and objective) basis to the echocardiographic diagnosis of regional asynergy [1, 2]. Unfortunately, a subjective component is still present even in a “reassuring” computerized quantification of regional wall motion: in this case, a subjective criterion is used in tracing endocardial and epicardial borders. However skilled the operator, the variability of the method depends upon several factors, such as quality of the echocardiographic instrument, and the observer’s familiarity with the computer and with the technique of outlining myocardial borders from stop-frame images. The quality of stop-frame images is worse than that of the image in motion as it is deprived of the dynamic integration in time and space that the eye performs naturally over a sequence of frames: at least 25% of the studies interpretable by qualitative criteria are unsuitable for a quantitative analysis. The task of outlining images can be extremely boring and often the same cardiac cycle has to be reviewed again and again before the observer may be reasonably sure of the edges to be traced. This is particularly true for images of suboptimal quality. Once end-systolic and end-diastolic epicardial and endocardial borders have been outlined, global and regional left ventricular function can be assessed.