The Cross‐sectional Echocardiogram in Clinical Cardiology: Applications and Relationship to the M‐mode Technique.

SUMMARY Until recently M‐mode echocardiography has been the standard in clinical practice. Although the M‐mode systems provide rapidly acquired, high resolution data concerning regional cardiac interface position and motion, the limited area encompassed by the narrow M‐mode beam and failure to provide spatial orientation may be a significant limitation in selected clinical areas. Cross‐sectional echocardiography expands the area of the heart which is available for study and displays the acoustic images in a dynamic spatially oriented format allowing the moving cross‐sectional anatomy of the heart to be visualized. This variation in method of display provides more extensive information concerning valvular heart disease by permitting analysis of the morphology and motion patterns of the cardiac valves, direct visualization of valvular orifices, and appreciation of valvular movement in relationship to surrounding cardiac chambers. In patients with ischemic heart disease the cross‐sectional systems increase the area of the ventricle which is available for ultrasonic study by adding the cardiac apex and the medial and lateral walls of the ventricle to the recorded data. In addition the systems permit localized distortion in left ventricular shape and function to be evaluated. Finally, in congenital heart disease the cross‐sectional systems permit the orientation of the great vessels and cardiac chambers to be determined. In this report we have presented examples of the applications of cross‐sectional echocardiography in each of these areas in the hope that the reader can gain from these isolated examples an overall appreciation of the potential of this type of instrumentation and its relationship to be more conventional M‐mode display.