Atrial and Ventricular Septa

Atrial and ventricular septal defects typically are not circular “holes,” but instead are complex structures, often irregularly shaped or fenestrated, that are difficult to visualize in two dimensions. RT3DE enables improved visualization of septal defects using unique en face representations of the interatrial and interventricular septa. The interatrial septum can be represented as viewed from the left or right atrium and the interventricular septum as viewed from the left or right ventricular side. This allows the creation of surgical views of the defects as well as improved understanding of their shape and relationships to surrounding intracardiac structures. These views also allow a more accurate measurement of defect size, including their dynamic shape change during the cardiac cycle.^2–4 The importance of viewing the defects from both sides of the septum cannot be overemphasized; this aids in understanding their anatomy and particularly facilitates the determination of both the right and left border edges and shapes.⁵ These measurements are useful for surgical or interventional planning in the catheterization laboratory (Figures 15-1 and 15-2; Videos 15-1 to 15-3).

Figure 15-1 A, Atrial septal defect viewed from the right atrium. Three-dimensional echocardiography more clearly demonstrates the defect’s margins and shape. The asterisk notes the septal defect. B, Atrial septal defect in a 4-year-old girl. The defect is viewed en face from the left atrial side, demonstrating its irregular margins. Both patients presented with incidental findings of murmurs and were asymptomatic but had significant right ventricular dilation. Both proceeded to elective closure of the defect via cardiac catheterization (see Video 15-1). IVC, inferior vena cava; LV: left ventricle; LVOT: left ventricular outflow tract; SVC, superior vena cava.

Figure 15-2 A, Perimembranous ventricular septal defect (VSD; asterisk) viewed from the left ventricle. This image is from a 6-month-old infant who had a routine echocardiogram performed as part of an investigation for dysmorphism with a possible genetic cause. This defect is small and does not cause symptoms or heart failure; a conservative management approach was therefore taken (see Video 15-2). B, Perimembranous VSD (asterisk) from a 2-year-old boy born prematurely at 34 weeks’ gestation who had a murmur detected while in the neonatal unit. This image demonstrates the relationship of the VSD to the tricuspid valve, by which it is partially shrouded (arrow, tricuspid valve tissue). The patient was asymptomatic and the VSD restrictive. Surgery is currently not planned (see Video 15-3). C, Subcostal view of a VSD (asterisk) with partial override of the aortic valve (AV) in a 4-month-old infant with tetralogy of Fallot diagnosed after birth. The dotted line marks the plane of the ventricular septum. This patient had elective surgical repair at the age of 5 months without complications (see Video 15-4). LA, left atrium; LV, left ventricle; LVOT, left ventricular outflow tract; RV, right ventricle.

Atrioventricular Valves

Transthoracic RT3DE is complementary to 2D transesophageal echocardiography (2DTEE) and 2D transthoracic echocardiography (2DTTE) in detecting anatomic and functional abnormalities of atrioventricular (AV) valves in patients with congenital heart disease.^6–8 This is mainly due to the unique 3D visualization and representation of the AV valves. RT3DE facilitates viewing of the mitral valve with its complex annular shape and interactions with the left ventricular shape and function and the subchordal apparatus.^7,9 RT3DE also facilitates increased understanding of the maturation of the dynamic function of the mitral valve. The mitral valve is saddle shaped, and its motion and dynamic function during the cardiac cycle are complex. In adults, the mitral valve annulus has its largest dimension at end systole and is smallest at end diastole.^10,11 However, RT3DE has demonstrated that in children, the mitral annular motion is somewhat different and that it has its largest area in systole and decreases in diastole.^12,13 The main advantage of 3DE is that the individual scallops of the mitral valve can be imaged in the same view, which helps define the surgical anatomy and enhances communication between the echocardiographer and the surgeon.

RT3DE has a clear advantage for imaging the tricuspid valve because the three leaflets are very difficult to view together by cross-sectional imaging. For congenital abnormalities of the tricuspid valve, RT3DE can be useful for a better representation of the valvar anatomy. A typical example is imaging of the tricuspid valve in Ebstein’s anomaly. In this lesion, RT3DE can provide better visualization of the morphology of the tricuspid valve leaflets, their attachments, their degree of coaptation, and the mechanism of regurgitation.¹⁴ The multiplanar review mode also facilitates appreciation of the degree of displacement and rotation of the tricuspid valve annulus, which is the key feature of this anomaly.⁷ Potentially, RT3DE could also help determine the right ventricular stroke volume, although no validation data on right ventricular volumes have been published yet in this disease (Figures 15-2 to 15-5; Videos 15-2 to 15-9).

Figure 15-3 A, Isolated cleft (asterisk) in the anterior leaflet of the mitral valve. The arrows demonstrate the free edges of the anterior leaflet. This patient also had large complex apical ventricular septal defects that were detected antenatally. The ventricular septal defects rapidly became restrictive and the mitral regurgitation was mild and well tolerated, so surgery can be deferred until the child is older (see Video 15-5). B, Mitral valve with prolapsing anterior (AL) and posterior (PL) leaflets from a 12-year-old boy. This patient presented with palpitations of unknown cause. He was found to have idiopathic dysplasia of the mitral valve and underwent successful mitral valve repair. The mitral valve is viewed in systole (left) and diastole (right) (see Video 15-6). C, Double-orifice mitral valve in a patient with transposition of the great arteries and a ventricular septal defect. This patient presented with cyanosis and tachypnea at 1 week of age. The asterisks mark the two orifices (see Video 15-7).

Figure 15-4 Ebstein’s anomaly of the tricuspid valve in a 13-year-old boy who presented with supraventricular tachycardia. Regurgitation was mild and the patient tolerated it well. A, A short-axis cut from the ventricular apex. The vertical arrow points to the septal leaflet, which has multiple abnormal attachments to the septum. The horizontal arrow points the anterosuperior leaflet, which has additional redundant tissue. The left ventricle (LV) is small (see Video 15-8). B, Displacement and rotation of the tricuspid valve toward the right ventricular outflow tract (RVOT); the arrow indicates the plane of opening of the valve (see Video 15-9). RV, right ventricle.

Figure 15-5 A 3-month-old infant presented with a double-outlet right ventricle and a large perimembranous ventricular septal defect (VSD) extending to the inlet septum and a straddling tricuspid valve. The great arteries are normally related. Because of the significant attachments of the tricuspid valve through the VSD into the left ventricle (LV, arrow), this patient was unable to have a two-ventricle repair and instead underwent successful single-ventricle palliation. In A, the three-dimensional dataset has been cropped to show the straddling valve. In B, the dataset has been cropped with the multiplanar review mode. Ao, aorta; LA, left atrium; PA, pulmonary artery; RA, right atrium; RV, right ventricle.

Atrioventricular Septal Defects

Patients with AV septal defects have a common AV junction with a single AV valve at the entrance of both ventricles. RT3DE can provide clear visualization of the anatomic variability, which is crucial in the preoperative planning. Studies have demonstrated that RT3DE can provide additional anatomic information to cross-sectional imaging in patients before and after surgical repair.^15–17 In preoperative assessment, the anatomy of the superior and inferior bridging leaflets, as well as that of the left-sided mural leaflet, provides useful clinical information. In postoperative patients with residual AV valve regurgitation, the mechanisms contributing to the regurgitation can be complex, and RT3DE can be useful in clarifying the origin of the regurgitant jets and in guiding surgical decision making by demonstrating defects such as residual cleft, central regurgitation, leaflet prolapse, dysplasia, annular dilation, and so on (Figures 15-6 and 15-7; Videos 15-10 to 15-12).

Figure 15-6 This patient had a balanced atrioventricular septal defect and trisomy 21 (Down syndrome). A, Four cardiac chambers with a deficient atrioventricular septum causing the ventricular septal defect (V) and primum atrial septal defect (1). There is an additional secundum atrial septal defect (2) (see Video 15-10). B, A view of the atrial and ventricular septa from the left ventricle. C, Subcostal view of the common atrioventricular valve. The common valve is composed of five leaflets, the superior and inferior bridging (SBL and IBL), left mural (LM), right mural (RM), and right anterior superior (RAS). This patient underwent echocardiography as screening for congenital heart disease when a postnatal diagnosis of trisomy 21 was made (see Video 15-11). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

Figure 15-7 This 12-year-old patient had left atrioventricular valve regurgitation following atrioventricular septal defect repair. A, The valve is closed. Note the thickening and rolling of both anterior (AL) and posterior (PL) leaflets. The arrow indicates the stitch line where the surgeon closed the zone of apposition between the superior and inferior bridging leaflets to create a bifoliate left atrioventricular valve. B, With the valve open, there is a tear in the leaflet (arrow) adjacent to the stitch line, which was an unusual source of valvar regurgitation in this patient. This echocardiographic study contributed to preoperative planning, and the patient was able to undergo successful repeat repair of the left atrioventricular valve (see Video 15-12).

Outflow Tracts

RT3DE allows accurate anatomic visualization of both left and right outflow tracts and is helpful in defining the mechanisms contributing to complex outflow tract obstruction.¹⁸ In both outflow tracts, the obstruction can be present at different levels (subvalvar, valvar, and supravalvar). In the left ventricular outflow tract, a subvalvar obstruction can be caused by a subvalvar membrane, abnormal AV valve tissue with septal attachments, or a tunnel-like obstruction. Here, RT3DE with multiplanar reconstructions can be helpful in defining the exact anatomic mechanisms. Semilunar valve abnormalities may, however, be well delineated by RT3DE, which has been demonstrated to correlate well with surgical findings.¹⁹

Subaortic obstructions usually are incompletely visualized by the surgeon, who approaches the lesion through the aortic valve. Therefore, accurate preoperative imaging is beneficial for surgical planning and may demonstrate additional lesions, such as abnormal mitral chordal attachments in subaortic stenosis.²⁰

The right ventricular outflow tract can be more difficult to visualize with RT3DE because of its anterior position. Right ventricular outflow tract obstruction also can be complex with subvalvar, valvar, and supravalvar components. The additional value of RT3DE still remains to be proven for this indication (Figures 15-8 to 15-11; Videos 15-13 to 15-18).

Figure 15-8 A 2-year-old child with subaortic stenosis and ventricular septal defect. There is a discrete subaortic ridge (A, horizontal arrow). In addition, there is a perimembranous ventricular septal defect (asterisk) partially occluded by tricuspid valve tissue (B, arrows) and minor prolapse of the right coronary cusp of the aortic valve (A, vertical arrow). This patient presented after premature birth with a murmur. Although he has remained asymptomatic, he requires careful echocardiographic follow-up to monitor for any progression of either the subaortic ridge or the aortic cusp prolapse (see Videos 15-13 and 15-14).

Figure 15-9 Tetralogy of Fallot in an unoperated 2-month-old patient, viewed from the subcostal position. There is anterior deviation of the outlet septum (arrow) causing a perimembranous ventricular septal defect (asterisk) and narrowing of the right ventricular outflow tract (RVOT). This patient presented at birth with dysmorphic features suggestive of 22q11 deletion, commonly associated with conotruncal cardiac defects, and underwent elective repair of the tetralogy of Fallot (see Video 15-15). RA, right atrium; RV, right ventricle.

Figure 15-10 Pulmonary valvar stenosis with thickening of the valve leaflets (arrows). A, Right ventricular (RV) outflow tract cropped from a three-dimensional dataset acquired from the subcostal position (see Video 15-16). LV, left ventricle; PA, pulmonary artery. B, A dataset acquired from the parasternal position showing an en face view of the valve with the leaflets open (top) and closed (bottom). This 6-month-old patient presented with a cardiac murmur and was found to have moderate pulmonary stenosis (see Video 15-17).

Figure 15-11 This 8-year-old boy has a bicuspid aortic valve. The arrows indicate the valve leaflets, shown in long-axis (A) and short-axis (B) views. He was referred in early childhood for screening because of a family history positive for significant cardiac abnormalities; his father had marfanoid aortic root dilation, and his sister had mitral valve prolapse. Genetic testing in the family was negative (see Video 15-18).

Valve Orifice

In certain congenital heart diseases, accurate assessment of valve size may be important in determining surgical management. RT3DE enables the operator to view the true plane of the valve orifice more accurately. For stenotic lesions, this allows direct measurement of the effective orifice using planimetry on 3D images.²¹ RT3DE for area calculation has been shown to be more reliable, with a lower interobserver variability, compared with cross-sectional imaging (Figure 15-12).²²

Figure 15-12 A patient with aortic stenosis. In the multiplanar review mode, the aortic valvar annulus has been transected in three planes, positioned such that two planes were in the valve’s long axis and perpendicular to each other and the third plane was in the true short axis of the valve. These three planes were used to define the hinge points of the valve; the short-axis plane was then slid to the leaflet tips to determine the valve’s effective orifice area, maintaining reference to the other two planes and tilting the plane, if necessary, to account for eccentric valve opening. The perimeter of the orifice was then planimetered to determine the area. This patient had two previous balloon aortic valvoplasties, the first at age 6 months and the second at age 13 years. This echocardiogram was performed just prior to his third valvoplasty at age 15 years, which yielded an excellent result, with significant relief of the transvalvar gradient.

Regurgitant Jets

Valvar regurgitation in patients with congenital heart disease may have complex mechanisms that are difficult to evaluate fully by 2DE; RT3DE helps elucidate these details. The regurgitant jet may have an irregular shape, which makes it more readily appreciated in 3D than in 2D (Figures 15-13 and 15-14; Video 15-19).

Figure 15-13 This patient has ulcerative colitis and presented at the age of 8 years with infective endocarditis affecting his mitral valve. After full resolution of the endocarditis, he had significant mitral regurgitation requiring surgical repair. A, Prolapse of the anterior leaflet (AL) of the mitral valve and restriction of movement of the posterior leaflet (PL) caused failure of coaptation. There is “folding” of the anterior leaflet (arrow) seen from the atrial aspect in B and the ventricular aspect in C. D, The multiplanar review allows more complete visualization of the complex shape of the regurgitant jet.

Figure 15-14 This 6-month-old patient with hypoplastic left heart syndrome, which was antenatally diagnosed, has had palliation in the form of a Norwood procedure, with the right ventricle (RV) acting as the systemic ventricle. There is significant tricuspid regurgitation. Note the thickening of the anterosuperior leaflet and the failure of coaptation of all three leaflets, with the regurgitant jet arising along all three commissures (see Video 15-19). AS, anterosuperior leaflet; P, posterior leaflet; RA, right atrium; S, septal leaflet.

Ventricular Volume and Mass Quantification

There are many congenital lesions in which quantification of left ventricular volume or mass is important. RT3DE demonstrates excellent intraobserver and interobserver reproducibility in left ventricular quantification.^23,24 This can be a useful adjunctive investigation in patients in whom determination of left ventricular adequacy is important for clinical decision making, such as in those with borderline left ventricles when the choice is either two-ventricle repair or single-ventricle palliation. In patients with a functional single ventricle, RT3DE measurements of mass and volume correlate well with cardiac magnetic resonance imaging (MRI) measurement and allow monitoring of ventricular size and function over time.²⁵

Evaluation of right ventricular function is extremely important in congenital heart disease, particularly in patients with right-sided lesions, such as tetralogy of Fallot, or in patients in whom the right ventricle is the systemic ventricle, such as in congenitally corrected transposition of the great arteries, or after an atrial switch procedure. 3DE has been demonstrated to be a sensitive tool to identify right ventricular dysfunction and also may be useful to assess which patients would benefit from quantitative analysis, for which cardiac MRI remains the gold standard.^26–28

RT3DE also allows excellent visualization of intracardiac masses, which may be monitored by RT3DE assessment of the volume of the mass (Figures 15-15 to 15-17; Videos 15-20 and 15-21).

Figure 15-15 A, This 18-month-old patient has a complete atrioventricular septal defect that is slightly unbalanced, with the left heart structures being smaller than those of the right heart. B, Left ventricular volume analysis, which can be helpful in borderline cases such as this, can be used to determine suitability for biventricular repair versus single-ventricle palliation. This patient underwent biventricular repair, which resulted in some left atrioventricular valve stenosis in the postoperative period; it resolved over time with somatic growth (see Video 15-20). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

Figure 15-16 This 16-year-old patient had surgical repair of tetralogy of Fallot in infancy, with a patch across the hypoplastic pulmonary valve annulus, which has left her with free pulmonary insufficiency. The right ventricle is progressively becoming dilated and is being carefully monitored by echocardiography and cardiac magnetic resonance imaging to determine the optimal time for pulmonary valve replacement. Commercially available software allows the operator to trace the right ventricular endocardial border in several planes (top panels) and then generates a three-dimensional model (bottom) and calculations of right ventricular volume and function.

Figure 15-17 This patient was antenatally detected to have a large mass in the right ventricle but was asymptomatic at birth. There is a large mass in the right ventricle (RV) that is not obstructing the tricuspid valve. This is a rhabdomyoma, which has a benign course. Because there is no obstruction to inflow or outflow, conservative management was chosen. A, A three-dimensional dataset acquired from the apex (see Video 15-21). B, Image acquired subcostally. RV, right ventricle; LV, left ventricle.

Dyssynchrony Assessment: Regional Left Ventricular Volumes

As in adults, RT3DE has been used to demonstrate left ventricular dyssynchrony in children with left ventricular dysfunction.²⁹ In congenital heart disease, dyssynchrony is an important mechanism that can contribute to ventricular dysfunction. Data on the potential use of timing of the regional volume changes for the diagnosis of dyssynchrony in patients with congenital heart disease are still limited.

Presurgical Imaging

RT3DE can be used to enhance preoperative planning of procedures by enhancing understanding of intracardiac anatomy. RT3DE reduces operation time by giving improved anatomic detail before surgery in some patients, such as those with complex outflow tract obstruction.¹⁸ Findings on RT3DE correlate well with anatomic and surgical findings in congenital heart disease in both simple and complex defects.^18,20,30 New, clinically important information that substantially alters the course of management may be discovered with RT3DE analysis in a small subset of patients.²⁰

Intraprocedural Imaging

Both intraoperative epicardial RT3DE and intraoperative RT3DTEE have been demonstrated to be useful in the immediate postbypass evaluation of surgical repair of congenital heart defects.³¹ Both techniques may provide particular additive value in the intraoperative imaging of AV valves.³² Transcatheter closure of atrial septal defects has traditionally been guided by 2DTEE or intracardiac echocardiography, but RT3DE is increasingly being used either alone or as an adjunct to 2DE. RT3DE may minimize the use of fluoroscopy in some procedures; for example, it has been successfully used in guiding endomyocardial biopsy of the right ventricle in children (Figures 15-18 to 15-20; Videos 15-22 to 15-24).³³

Figure 15-18 This 2-year-old patient has double-outlet right ventricle, with the aorta (Ao) rightwards of the pulmonary artery (PA). A, A subcostal image with the tricuspid valve closed. The asterisk marks the ventricular septal defect. B, The tricuspid valve opening toward the outflow tract, an important view for planning surgical repair. The patient initially had been directed toward single-ventricle palliation but after this assessment had a successful biventricular repair (see Video 15-22). AS, Anterosuperior leaflet; LV, left ventricle; P, posterior leaflet; RV, right ventricle; S, superior leaflet.

Figure 15-19 Intraoperative live three-dimensional transoesophageal echocardiography from a 13-year-old patient with aortic regurgitation undergoing surgical repair. A, After the first bypass run and attempted repair, there was still a significant residual coaptation defect (arrow) causing significant aortic insufficiency. B, After the second bypass run, guided by this image, excellent coaptation of all three leaflets was seen, and there was no significant regurgitation. The patient made an excellent recovery from surgery and is now asymptomatic. L, Left coronary cusp; N, noncoronary cusp; R, right coronary cusp.

Figure 15-20 While undergoing balloon dilation of the aortic valve for severe aortic stenosis, this 5-year-old patient developed severe aortic insufficiency after the second inflation of the balloon. A, A dataset acquired from the parasternal position shows the right coronary cusp (arrow) to be flailing (see Video 15-23). B, View from the apical position in systole (left) and diastole (right). The patient proceeded to a successful Ross procedure a few weeks later (see Video 15-24).