Echocardiography in the neonate and young infant.

The neonate and young child present unique problems in echocardiographic diagnosis because of the wide spectrum of possible abnormalities and the tendency toward multiple lesions, requiring clear visualization of all great veins and arteries as well as intracardiac structures. Performance and interpretation of echocardiograms in this age group require an extensive knowledge of the pathologic anatomy of congenital heart disease. Recognition of unusual lesions is facilitated by displaying the heart in an anatomically familiar (upright) format in order to draw from experience in angiography and pathology. The subxiphoid (subcostal) transducer position provides a flexible acoustic window for scanning the heart and great vessels in a multitude of planes, providing a general orientation for each cardiac segment. All other transducer positions are utilized to provide specific anatomic information. Although in this age group echocardiographic visualization of intracardiac anatomy is superior to other techniques, delineation of the great vessels remains its greatest limitation. Tortuous vessels may not lie in a single plane and, therefore, cannot always be displayed throughout its length by a "slice" technique such as echocardiography. In addition, limited focal range of most high frequency transducers is a continuing impediment to imaging structures in the posterior and superior mediastinum. Echocardiography provides a cost-effective means for identifying the neonate with life-threatening cardiovascular disease. It provides a complete and definitive anatomic diagnosis, in some cases eliminating the need for further procedures, while in others, improving the timing and performance of cardiac catheterization. Future studies should investigate the proper utilization of echocardiography as adjunct to or replacement of other techniques in the management of the young child.