Andersons pediatric cardiology 806

Figs 31.19C and 31.21) The perimembranous ventricular septal defect opening to the inlet of the right ventricle will also demonstrate lack of offsetting between the atrioventricular valves (see Chapter 32) Hence the trifoliate nature of the left atrioventricular valve, along with the gooseneck appearance of the left ventricular outflow tract, distinguishes the atrioventricular septal defect in this setting from that of the perimembranous inlet ventricular septal defect Rarely a left atrioventricular valve with three leaflets may be the only manifestation of patients having an atrioventricular septal defect with a common atrioventricular junction, the atrial and ventricular septal structures being intact Such patients may well present as having “mitral” regurgitation, with the true nature of their spontaneously closed atrioventricular septal defect not initially being recognized The diagnostic echocardiographic hallmarks, however, are the same as for the other forms of atrioventricular septal defect.5,52 Other less common variants found with separate atrioventricular valvar orifices, such as common atrium and so-called double-outlet left or right atrium, are easily recognized in a complete echocardiographic examination FIG 31.19 Apical four-chamber plane in systole demonstrate how the relationship of the common atrioventricular valve helps to determine the degree of atrial- and/or ventricular-level shunting (A) The common atrioventricular valve is firmly attached to the crest of the muscular ventricular septum with exclusively atrial-level shunting, the so-called partial atrioventricular septal defect (B) The common atrioventricular valve again appears to be attached to the crest of the muscular ventricular septum, with large atrial-level shunting; however, in the two-dimensional view there is suggestion of possible ventricular-level shunting, the so-called transitional defect, which would need to be interrogated by color Doppler (C) The common atrioventricular valve is firmly attached to the leading edge of the primary atrial septum with exclusively ventricular-level shunting The common atrioventricular valve would be partitioned into two separate valve orifices (D) The common atrioventricular valve resides approximately midway between the leading edge of the primary atrial septum and the crest of the muscular ventricular septum, with significant atrial- and ventricular-level shunting, the so-called complete defect la, Left atrium; lv, left ventricle; ra, right atrium; rv, right ventricle FIG 31.20 Subcostal paracoronal echocardiographic two-dimensional (A) and color Doppler (B) images demonstrating an atrioventricular septal defect with exclusively atrial-level shunting The atrial component of the defect is profiled well in this plane la, Left atrium; lv, left ventricle; ra, right atrium FIG 31.21 images from a patient with an atrioventricular septal defect with separate atrioventricular valve orifices and an intact atrial septum (A) Attachment of the common atrioventricular valve to the leading edge of the primary atrial septum, partitioning the valve into two effective orifices and allowing exclusively ventricular shunting with lack of offsetting of the atrioventricular valves (B) Subcostal short-axis plane image demonstrating the separate atrioventricular valvar orifices of the common junction, separated by bridging tissue The three leaflets are best visualized in a slightly angulated paracoronal plane ibl, Inferior bridging leaflet; la, left atrium; lv, left ventricle; ml, mural leaflet; rv, right ventricle; rvot, right ventricular outflow tract; sbl, superior bridging leaflet