Annotated References Soto B, Becker AE, Moulaert AJ, Lie JT, Anderson RH Classification of ventricular septal defects Br Heart J 1980;43:332–343 This classification with obvious clinical relevance was based on study of hearts with concordant atrioventricular and ventriculoarterial connections The ventricular septum itself was viewed as having muscular and membranous portions, the muscular septum being divided into inlet, trabecular, and outlet components Defects observed in the area of the membranous septum were termed perimembranous, distinguishing them from muscular defects and those in the area of septum subjacent to the arterial valves, termed subarterial infundibular defects Perimembranous defects could be found extending either toward the inlet, apical, or outlet components of the right ventricle Muscular defects were found opening to the inlet, apical trabecular, and outlet components of the right ventricle These observations form the basis of classifying such defects in clinical practice Soto B, Ceballos R, Kirklin JW Ventricular septal defects: a surgical viewpoint J Am Coll Cardiol 1989;14:1291–1297 This anatomic study categorizes ventricular septal defects from a surgical viewpoint The defects are classified as being conoventricular, in the right ventricular outlet, in the inlet septum, or in the trabecular septum, with each category having several subcategories Emphasis is placed on the relations of the defects to the left ventricular outflow tract The borders of the ventricular septal defects are described in detail, with use of the prefix “juxta” to indicate the immediate adjacency of the defect to a structure such as the tricuspid valve Taken together with the classification discussed earlier, this provides the foundation of the terminology used today Capelli H, Andrade JL, Somerville J Classification of the site of ventricular septal defect by 2dimensional echocardiography Am J Cardiol 1983;51:1474–1480 Cheatham JP, Latson LA, Gutgesell HP Ventricular septal defect in infancy: detection with two dimensional echocardiography Am J Cardiol 1981;47:85–89 Sutherland GR, Godman MJ, Smallhorn JF, et al Ventricular septal defects Two dimensional echocardiographic and morphologic correlations Br Heart J 1982;47:316–328 These studies utilized cross-sectional echocardiography to identify and classify ventricular septal defects Multiple precordial and subcostal echocardiographic planes are described Defects visualized were classified on the basis of the structures that formed their margins, and correlations were made angiographically, surgically, and pathologically Echocardiography was reliable in identifying subaortic, inlet, small, moderate, and large subtricuspid, large subpulmonary, and large central and apical muscular ventricular septal defects These studies describe the initial views used today in routine clinical practice to image and classify ventricular defects Chen FL, Hsiung MC, Nanda N, Hsieh KS, Chou MC Real time three-dimensional echocardiography in assessing ventricular septal defects: an echocardiographic-surgical correlative study Echocardiography 2006;23:562–568 This study examines the potential value of real-time three-dimensional echocardiography in accurately and quantitatively estimating the size of ventricular septal defects, correlating observations with surgical findings The