This study was designed to identify the ultrasound echoes originating from the left ventricle. Injections of indocyanine green and saline were made directly in the left ventricular cavity via a cardiac catheter in patients undergoing routine diagnostic cardiac catheterization. The injections produced a cloud of echoes that filled the left ventricular cavity and outlined the left side of the interventricular septum and the endocardial surface of the posterior left ventricular wall. The results of this study verified the origin of echoes that are vital to the ultrasound technics for the detection of pericardial effusion, left ventricular wall size, left ventricular cavity size, and left ventricular stroke volume. This study also provided ways of distinguishing between the true left ventricular wall echoes and intracavitary echoes that often cause confusion.
Feigenbaum et al. (Wed,) studied this question.