FIG 33.12 Echocardiographic images showing tomograms taken in an apical four-chamber plane of a normal heart (left) and a heart with Ebstein malformation (right) The hinge point of the normal septal tricuspid leaflet is positioned slightly toward the cardiac apex relative to the septal hinge point of the anterior mitral leaflet (outlined by the arrows at left) This displacement is exaggerated in hearts with Ebstein malformation, as shown at right This can be quantitated by the displacement index, dividing the distance between the septal valvar insertions by the body surface area A value of greater than 8 mm/m2 is diagnostic of Ebstein malformation It should be noted that the valvar leaflets are also abnormal in Ebstein malformation In the case illustrated, the leaflets are thickened and moderately dysplastic LA, Left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle Other echocardiographic features can aid in making the diagnosis, including elongation of the anterosuperior leaflet, tethering of leaflets to the underlying myocardium, shortened chordal support, attachment of the leading edge of the anterosuperior leaflet to the right ventricular myocardium, displacement of the annular attachment of the inferior (and less often the anterosuperior) leaflet, absence of the septal or inferior leaflets, congenital fenestration of the leaflets, and enlargement of the valvar annulus Complete echocardiographic assessment should include a complete segmental examination, with special attention to definition of the tricuspid valve apparatus, and description of the functional status/size of the right ventricle, the pulmonary valve/arteries, and the atrial septum Valvar assessments focus on the size and mobility of each leaflet, the degree of leaflet adherence to the RV myocardium, and the functional impact (regurgitation or obstruction) resulting from these anatomic deformities This information is critical to the decision-making process and the timing of surgical interventions Over the past decade, the “cone” repair has been found to be a very effective approach to tricuspid valve reconstruction in patients with Ebstein malformation and in some series has been successfully applied to more than 90% of patients Previous “monoleaflet” repairs were successful in much a smaller percentage of patients and relied primarily on anterior leaflet mobility to “coapt” with the ventricular septum In contrast, the cone reconstruction uses all available leaflet tissue, including tissue surgically delaminated at the time of the repair This allows creation of a circumferential cone of leaflet tissue surrounding the effective valve orifice This technique also relocates the annular hinge point to the level of the atrioventricular groove and relies on chordal support from the right ventricular apex As a result, the presence/size of a mobile septal leaflet, which provides an anchor to the cylindrical valve reconstruction, has taken on greater importance in the prerepair assessment Traditionally, the most important determinant of a durable monoleaflet repair was a freely mobile anterosuperior leaflet, especially its leading edge The presence of such a mobile leaflet remains a favorable finding, simplifying the cone reconstruction because less “surgical delamination” will be required in these cases (Fig 33.13) Extensive adherence of the anterosuperior leaflet to the ventricular myocardium (Fig 33.14) made a monleaflet repair impossible However, a cone reconstruction may still be possible, albeit more challenging, in these patients (Fig 33.15, Videos 33.1 to 33.4) A single central jet of regurgitation is more easily eliminated than are multiple regurgitant orifices using any technique (see Fig 33.11) Even when there is a significant amount of leaflet tissue present, direct muscular insertions from the ventricular free wall into the body of the anterosuperior leaflet can make any repair more difficult (Fig 33.16) Other important features requiring preoperative definition include the degree of dysfunction and dilation of the anatomic right ventricle, the presence and size of any atrial septal defect, and the performance of the functional tricuspid valve leaflets (degree of regurgitation/stenosis).29,48,49 FIG 33.13 Apical four-chamber inflow images of a patient with Ebstein malformation The left frame is from mid-diastole The middle and right frames are from mid- and end-systole, respectively Features that suggest favorable anatomy for monoleaflet repair are that the anterior leaflet in this patient is freely mobile, including its leading edge (arrows) There are no muscular insertions that limit or distort the motion of the valve The regurgitant jet originated only from the gap in coaptation seen between the anterior leaflet and the remnant of the septal leaflet The leading edge of the valve reaches a point near enough to the septum that, given the degree of annular dilation, an annuloplasty can advance it to a point where it will coapt with the septum and the vestiges of the septal leaflet LA, Left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle (Modified from Cetta F, Edwards WD, Seward JB, et al, Congenital heart disease In: Vannan MA, Lang RM, Rakowski H, Tajik AJ, eds Atlas of Echocardiography Philadelphia: Current Medicine LLC; 2005.) FIG 33.14 Anatomic specimen (left) and echocardiographic four-chamber image (right) demonstrating extremely severe examples of Ebstein malformation No remnants of the septal leaflet are present within the inlet Even the anterior leaflets have failed to fully delaminate in these hearts,