The identification of the cardiac chambers without contrast injection is a natural outcome of this study and depends on the distinguishing of key anatomic structures, the relationship of the chambers to them, and the recognition of movement patterns that may be specific for a structure or chamber. It is based on the intracardiac injection of substances that produce echoes at the site of injection as well as downstream in the flow pattern and permit identification of the heart cavities.
The purpose of this presentation is to describe a method for the ultrasonic identification of the cardiac chambers in the living subject. Even here, however, Edler (7) has gained useful knowledge in the recognition of the origin of these echoes by the passing of needles into cadavers in duplication of the path of the ultrasonic beam and by the study of excised hearts. On the other hand, the extension of the ultrasonic method to the study of other cardiac structures has been slow because of the difficulty in recognizing the source of the echoes. The tricuspid valve can also be detected (4), and studies have been made of left ventricular stroke volume (5) and wall thickness (6). Ultrasound cardiography has become established as a valuable clinical tool in the detection of pericardial effusion (1) and the study of mitral valve disease (2, 3).
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