Echocardiography, as cardiac catheterization, was first approached in a descriptive, qualitative sence where M-mode echo features of tetralogy of Fallot, pericardial effusions, tumors and other conditions could be recognized from a given echo pattern. Subsequently, the technique was used quantitatively for the measurement of chamber and vessel dimensions and of cardiac wall thickness. Another recent advance in echocardiography involves the use of echo while hand injecting nonviscous materials (saline, 5 per cent dextrose in water, cardio-green dye) into a vein or artery. This technique gives flow information and can be likened somewhat to angiography. After its inception in Europe, two-dimensional echocardiography was introduced here in 1971 when Sahn and coworkers showed that two-dimensional echocardiography allowed evaluation of spatial anatomy of the heart. This technique has been useful, especially in complex congenital heart defects. Recently, instrumentation and clinical application of two-dimensional echocardiography have become increasingly sophisticated and the technique more widely used. Accordingly, the clinician should be familiar with it. Additionally, echocardiography has been combined with range-gated pulsed Doppler so that flow information can be recorded noninvasively from a known chamber or vessel without the need for contrast injections. In this article the authors discuss the principles of diagnostic ultrasound and various types of echo instrumentation and usage. Three lesions (patent ductus arteriosus, aortic stenosis, and transposition of the great vessels) will be presented to illustrate the application of various echo techniques and instruments. Many textbooks and papers have been written about echocardiography and the reader is referred to them for details not covered in this review.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health