1. Answer: D. The subcostal imaging window is optimal to demonstrate the atrial septum and any associated ASDs that may be present. To visualize the atrial septum without potential drop-out, the imaging plane of sound should be perpendicular to the cardiac structure of interest. With respect to the atrial septum, the imaging plane that is optimally perpendicular is the subcostal 4-chamber and sagittal views. ASDs can be demonstrated in other imaging windows including the parasternal short-axis, apical 4-chamber, and high right parasternal views but care must be taken not to diagnose an ASD when the plane of sound is more parallel to the atrial septum creating the potential for false drop-out in the two-dimensional image. The addition of color Doppler and spectral Doppler interrogation in these views may also facilitate the diagnosis of an ASD.

2. Answer: A. Sinus venosus ASDs are most commonly associated with anomalous connection of the right pulmonary veins. Either a single right upper pulmonary vein or the right upper and middle pulmonary veins insert anomalously to the superior vena cava (SVC) or the SVC-right atrial junction. Sinus venosus defects are found most commonly in the superior portion of the atrial septum creating a “biatrial” insertion of the SVC. These defects can also be located inferiorly near the entrance of the inferior vena cava into the right atrium. Inlet VSDs are most commonly associated with atrioventricular septal defects. Bicuspid AV can be an isolated anomaly or is frequently seen in patients with coarctation of the aorta. A persistent left superior vena cava is seen in approximately 10% of patients with congenital heart disease but is not frequently associated with a sinus venosus ASD. Coarctation of the aorta is seen commonly with other left-sided obstructive lesions but not commonly with a sinus venosus ASD.

3. Answer: D. Patients with Down syndrome (trisomy 21) have an almost 50% incidence of congenital heart disease, with AVSDs being the most common cardiac anomaly in this cohort. AVSD in association with tetralogy of Fallot is a common constellation of cardiac anomalies in patients with Down syndrome. Obstruction of the left ventricular outflow tract (LVOT) and coarctation of the aorta are also common cardiac abnormalities in patients with AVSD but are not as common in Down syndrome patients. LV hypoplasia can occur in the setting of AVSD (“unbalanced AVSD with right ventricular [RV] dominance”) but is less commonly seen in this cohort. Aortic valve stenosis and anomalous pulmonary venous connections are uncommon.

4. Answer: D. Anatomic hallmarks of AVSDs include a cleft in the anterior leaflet of the left atrioventricular valve, lateral rotation of the LV papillary muscles, and attachments of the left and right atrioventricular valves at the same level at the cardiac crux. In addition, due to the absence of the atrioventricular septum in these defects, the LV inflow is shortened and the LV outflow is elongated (“goose-neck deformity”) creating a ratio of LV inlet to LV outlet ratio <1. Due to the presence of a common atrioventricular valve, the aortic valve is no longer “wedged” between the tricuspid and mitral valves and is pushed anteriorly (“sprung”).

5. Answer: D. Subpulmonary VSDs are located adjacent to the pulmonary valve and aortic valve and have been termed subpulmonary, supracristal, or doubly committed defects. These defects can be optimally demonstrated in the parasternal short-axis scan plane but can also be demonstrated from the subcostal and apical windows with appropriate angulation into the right ventricular outflow tract (RVOT).

6. Answer: A. Aortic insufficiency is the most common associated abnormality because of prolapse of the aortic cusp into a subpulmonary VSD. While this associated prolapse of aortic tissue limits the size of the VSD and can lessen the left-to-right shunt, the progression of aortic insufficiency due to distortion of the aortic valve is well recognized. If this regurgitation is significant and progresses, then surgical closure is indicated (and is not dependent upon the size of the left-to-right shunt). LVOT obstruction is more characteristically present in patients with a posteriorly malaligned VSD or an atrioventricular septal defect while RV outflow tract obstruction is the hallmark of anterior malalignment VSDs in tetralogy of Fallot. Pulmonary stenosis and aortic stenosis are not characteristic findings in a patient with a subpulmonary VSD.

7. Answer: C. Large VSDs result in equalization of right and left ventricular pressures as well as elevated pulmonary arterial pressure. Left-to-right shunting at the ventricular level results in a substantial increase in pulmonary blood flow with left atrial and ventricular volume overload. Systemic blood flow is not significantly increased in this setting.

8. Answer: B. The most common type of subaortic stenosis is related to a discrete membrane proximal to the aortic valve within the LVOT. This membrane is most often circumferential and can be adherent to both the aortic valve as well as the anterior leaflet of the mitral valve. LVOT obstruction in the setting of hypertrophic cardiomyopathy is often related to asymmetric septal hypertrophy in combination with systolic anterior motion of the mitral valve chordal and leaflet tissue. Anomalous mitral chordal insertions within the LVOT can be isolated or found in association with congenital heart disease and may result in obstruction but are not as common as discrete membranes.

9. Answer: A. Utilizing the simplified Bernoulli equation to obtain the peak instantaneous gradient across the pulmonary valve, 4 × [velocity]², then 4 × [4.1]² = 67 mm Hg.

10. Answer: A. Bicuspid aortic valve is the most commonly associated cardiac finding in patients with simple coarctation with some studies showing as high as an 80% occurrence in patients with coarctation. ASDs and VSDs are also common in patients with coarctation. Pulmonary valve stenosis and coronary arterial anomalies are much less frequent in this cohort.

11. Answer: C. The aortic lumen must be narrowed by at least 50% to significantly affect systemic arterial pressure.

12. Answer: C. The most common VSD associated with coarctation is a perimembranous defect. While less common, a posterior malalignment VSD often results in severe coarctation or interruption of the aortic arch. Muscular VSD as well as inlet VSD can also occur in the setting of coarctation, in particular with an unbalanced RV-dominant AVSD. Anterior malalignment VSDs are more commonly associated with RV outflow obstruction, most notably tetralogy of Fallot.

13. Answer: A. The systolic jet in patients with supravalvar aortic stenosis propagates further than the jet originating with aortic valvar stenosis and has a tendency to be entrained along the aortic wall thereby transferring its kinetic energy into the right innominate artery. This physical principle, termed the Coanda effect, often is expressed clinically in these patients by marked discrepancy in upper arm blood pressures, with the right arm pressure higher than the left arm blood pressure.

14. Answer: A. Interruption of the aortic arch is most commonly found in DiGeorge syndrome and is a deletion in chromosome 22q11. This chromosome deletion results in conotruncal defects, with interruption of the aortic arch type B being the most frequent cardiac abnormality. Down syndrome (trisomy 21) is frequently associated with congenital heart disease, most commonly atrioventricular canal defects and VSDs. Turner syndrome (45 XO) has coarctation and bicuspid aortic valve as hallmark lesions while Holt-Oram is associated with secundum ASDs. Alagille syndrome is most characteristically associated with pulmonary branch stenosis or RVOT obstruction.

15. Answer: D. Type A interruption of the aortic arch occurs distal to the origin of the left subclavian artery. Type B interruption occurs between the left common carotid and left subclavian arteries. Type C interruption occurs between the right innominate and left common carotid arteries.

16. Answer: A. The parasternal short-axis image in Figure 30-1 is a classic demonstration of a membranous VSD adjacent to the tricuspid valve. Color Doppler demonstrates a high-velocity mosaic jet from the left ventricle to the right ventricle. Muscular VSDs in the trabecular septum are best demonstrated in the apical 4-chamber and parasternal long- and short-axis views. Aneurysmal septal tricuspid leaflet tissue that obliterates a membranous VSD resulting in absence of a left to right shunt is termed a membranous septal aneurysm. While aortic insufficiency can rarely be associated with a membranous VSD, it is not demonstrated in this figure. Pulmonary valve stenosis can also be present in the setting of a VSD but is also less common.

17. Answer: D. The apical 4-chamber image in Figure 30-2 demonstrates the muscular ventricular septum with a midmuscular defect occluded by a closure device. The apical 4-chamber view demonstrates the inlet portion of the ventricular septum (near the atrioventricular valves) and the mid and apical muscular septum. Membranous VSDs can also be closed with these types of devices and would be best visualized in the apical and parasternal short-axis imaging planes. Due to their proximity to either the atrioventricular valves (inlet VSD) or semilunar valves (supracristal VSD), these VSDs are not candidates for device closure in the cardiac catheterization laboratory.

18. Answer: C. The parasternal short-axis image in Figure 30-3 demonstrates a defect in the subpulmonary region (supracristal) of the ventricular septum adjacent to the pulmonary valve. This defect has also been termed an infundibular or conal VSD due to the defect’s position within the infundibular muscular septum. Membranous VSDs are also demonstrated best in the parasternal short-axis scan plane but are adjacent to the tricuspid valve (within the membranous septum) instead of the pulmonary valve (within the infundibular septum). Inlet VSDs are best imaged in the apical 4-chamber plane and are adjacent to the atrioventricular valves. Trabecular muscular VSDs can be imaged in multiple imaging planes including the parasternal longand short-axis, subcostal, and apical views. Anterior malalignment VSDs are the hallmark of tetralogy of Fallot and are optimally imaged in the parasternal short- and long-axis as well as the subcostal imaging planes.

19. Answer: D. The high left parasternal short-axis image in Figure 30-4 demonstrates a patent ductus arteriosus. Color Doppler is consistent with a left-to-right shunt from the aorta to the pulmonary artery (red color flow). Continuous-wave Doppler confirms an exclusive left-to-right shunt in both systole and diastole. The peak Doppler velocity is approximately 4.0 m/s predicting a peak instantaneous pressure gradient of 64 mm Hg utilizing the simplified Bernoulli equation.

20. Answer: D. The high left parasternal short-axis image in Figure 30-5 demonstrates a PDA. Color Doppler is consistent with a bidirectional shunt from the aorta to the pulmonary artery (right-toleft shunting in systole and left-to-right shunting in diastole). Continuous-wave Doppler confirms bidirectional low-velocity shunting consistent with pulmonary hypertension.

21. Answer: B. The parasternal long-axis image in Figure 30-6 demonstrates a circumferential subaortic membrane within the LVOT (see arrow). Note the significant narrowing of the LVOT and the association of the membrane with the anterior leaflet of the mitral valve. The peak Doppler velocity obtained from a high right parasternal location predicts a mean gradient of ˜34 mm Hg (moderate stenosis). While aortic stenosis cannot be excluded from this still frame image, the major obstruction appears to be the membrane within the LV outflow tract. No systolic anterior motion (SAM) or anomalous mitral valve chord is demonstrated within the LVOT. Cardiac rhabdomyomas can rarely be present within the cardiac chambers or be adherent to cardiac valves, including the aortic valve; however, the majority of rhabdomyomas are intramyocardial, most typically within the LV or RV myocardium.

22. Answer: A. The apical 4-chamber image in Figure 30-7 demonstrates a large primum ASD. The large left-to-right shunt is demonstrated across this defect by color flow imaging (arrow). Both atrioventricular valves are inserted at the same level at the cardiac crux consistent with an AVSD with a large primum component. No shunt is evident at the ventricular level. Significant atrioventricular valve regurgitation is also demonstrated by color Doppler. Sinus venosus ASDs are uncommon in the setting of an atrioventricular VSD and would be best demonstrated in the subcostal sagittal imaging plane. Malalignment outlet VSDs (posterior malalignment with LVOT obstruction or anterior malalignment with RVOT obstruction) are best imaged in the parasternal long- and short-axis imaging planes or anteriorly in the apical 4-chamber orientation. A persistent left SVC is also imaged optimally in the apical 4-chamber view with the plane of sound angled posteriorly demonstrating the dilated coronary sinus emptying into the right atrium. A left SVC can also be imaged well from the parasternal long-axis and high left parasternal windows.

23. Answer: C. The suprasternal long-axis image of the aortic arch in Figure 30-8 demonstrates a juxtaductal coarctation of the aorta. Note the posterior shelf present in the descending aorta in the twodimensional image and the area of coarctation demonstrated with color Doppler. Both LPA branch stenosis and PDA would be best imaged in the parasternal short-axis or high left parasternal imaging planes. D-TGA, with a parallel relationship of the great arteries, would be best visualized in the parasternal long-axis, subcostal, and suprasternal short-axis windows. Interruption of the aortic arch can be imaged in the suprasternal and subcostal windows but has lack of continuity between the aortic segments with supply to the distal arch via the PDA.