1. (D) This clinical scenario is most consistent with a diagnosis of Alagille syndrome. Alagille syndrome is an autosomal dominant disorder associated with liver disease secondary to bile duct paucity, cholestasis, congenital heart disease (CHD), skeletal or ocular abnormalities, or typical facial features. Mutations in the Notch ligand, JAG1, are responsible for the clinical phenotype. Alagille syndrome is characterized by right-sided heart disease including peripheral pulmonary stenosis (diffuse hypoplasia of the pulmonary arterial bed as well as discrete stenosis), pulmonary valve stenosis, and tetralogy of Fallot (TOF). Left-sided lesions and septal defects have also been reported.

NOTCH1 mutations result in aortic valve pathology but not the other findings given here. PTPN11 mutations result in Noonan syndrome (characterized by hypertelorism, ptosis, short stature, and CHD, most commonly pulmonary valve stenosis and HCM). Additional cardiac manifestations include secundum-type atrial septal defect, VSD, TOF, pulmonary artery stenosis, coarctation of the aorta, partial AVSD (primum-type atrial septal defect), and polyvalvulopathy. Other noncardiac anomalies of Noonan syndrome include webbed neck, skeletal anomalies, bleeding diathesis, lymphatic disorders, mental retardation, and cryptorchidism. TBX1 is a gene that resides in the area of chromosome 22q11; mutations of TBX1 lead to features of DiGeorge syndrome (hypocalcemia, immunodeficiency, and severe CHD, most commonly interruption of the aortic arch [IAA] type B, truncus arteriosus, or TOF). GATA4 mutations appear to be involved in septation defects but are not associated with a classic syndrome as described in the vignette.

2. (E) Heart defects in congenital rubella syndrome include pulmonary stenosis (valvar, supravalvar, or peripheral) and patent ductus arteriosus. Tetralogy of Fallot has also been reported.

3. (E) Caffeine intake during pregnancy has not been shown to result in an increased risk of congenital heart disease in the fetus.

4. (C) Women with maternal phenylketonuria who have high levels of phenylalanine when pregnant have a high likelihood of having children with microcephaly and mental retardation. There is an increased risk for left-sided defects, septal defects, and tetralogy of Fallot.

5. (D) This vignette describes Williams syndrome, which is characterized in part by CHD, hypercalcemia in infancy, skeletal and renal anomalies, cognitive deficits, social personality, and so-called “elfin facies.” Approximately 90% of patients with the clinical diagnosis of Williams syndrome have a deletion at chromosome 7q11.23, which is not generally apparent on a routine karyotype but can be detected by FISH. Approximately 55% to 80% of patients with Williams syndrome have CHD, which typically includes supravalvar aortic stenosis and/or supravalvar pulmonary stenosis. Therefore, a click may not be present despite a murmur and significant gradient across the involved outflow tract.

18q deletion is associated with ASD, VSD, and pulmonary stenosis and is also associated with cleft palate and GU anomalies. Tetrasomy 22p is known as “cat eye syndrome” and is associated with rectoanal anomalies, coloboma, genitourinary anomalies, and preauricular pits/tags. Deletion of 8p23 is associated with septal defects, GU anomalies, abnormally formed ears, and minor hand anomalies. Chromosome 22q11 deletion is known as DiGeorge syndrome or velocardiofacial syndrome and is characterized by hypocalcemia, immunodeficiency, and severe CHD, most commonly IAA type B, truncus arteriosus, or TOF.

6. (C) Approximately 55% to 80% of patients with Williams syndrome have congenital heart disease, which typically includes supravalvar aortic stenosis and/or supravalvar pulmonary stenosis. The degree of cardiovascular involvement varies widely. Supravalvar pulmonary stenosis tends to improve with time, while supravalvar aortic stenosis usually progresses. Sudden death has been described in Williams syndrome. Suspected etiologic factors include coronary artery stenosis and severe biventricular outflow tract obstruction. Presumably, sudden cardiac death results from myocardial ischemia, decreased cardiac output, or arrhythmias. Patients with Williams syndrome are prone to develop hypertension because of renal artery stenosis.

7. (C) This scenario describes trisomy 18. The distinctive phenotype of trisomy 18 includes growth retardation, short palpebral fissures, small mouth, and micrognathia. Specific features include a prominent occiput, short sternum, small nipples, clenched hands, disorganized or hypoplastic palmar creases, hyperconvex nails, and “rocker bottom feet.” Congenital heart disease is the rule (>90% incidence). Most common associated defects include perimembranous VSD, TOF, DORV, and polyvalvular dysplasia. Approximately 90% of affected individuals die in the first year of life and usually not of their heart disease.

8. (C) The most common CHDs associated with a 22q11 deletion include tetralogy of Fallot, interrupted aortic arch type B, truncus arteriosus, perimembranous VSD, and aortic arch anomalies. A wide range of CHDs has been reported in patients with a 22q11 deletion, including pulmonary valve stenosis, atrial septal defect, heterotaxy syndrome, and hypoplastic left heart syndrome.

9. (E) This clinical scenario describes pulmonary hypertension resulting from a large unrepaired atrial septal defect. Although rare, severe irreversible hypertensive pulmonary vascular disease can develop from unrepaired ASDs. There is a female preponderance for this association. Spontaneous closure is rare for defects >8 mm in size. Although severe mitral regurgitation, nonsustained VT, and LV diastolic dysfunction can contribute to dyspnea on exertion, they are not the primary cause as indicated by this scenario.

10. (D) In general, cardiac catheterization is unnecessary for the diagnosis of sinus venosus ASD. Occasionally, however, questions about pulmonary vascular obstructive disease or associated cardiac defects arise that require catheterization. In this case, it is important to assess the presence and degree of pulmonary vascular vasoreactivity to determine appropriate treatment. It would be premature to start therapy without a thorough understanding of the pulmonary artery pressures and reactivity.

11. (B) Sinus venosus ASD accounts for 5% to 10% of ASDs and is located posterior and superior to the fossa ovalis. The sinus venosus defect commonly is associated with anomalous connection of the right pulmonary veins to either the right atrium or the superior vena cava near the caval-atrial junction. Electrocardiogram shows that about half of patients have a frontal plane P-wave axis of <30 degrees. The other types of ASDs are associated with normal P-wave axes.

12. (A) The complete form of AVSD is characterized by a large septal defect with interatrial and interventricular components and a common atrioventricular valve that spans the entire septal defect. The septal defect extends to the level of the membranous ventricular septum, which is usually deficient or absent.

The common atrioventricular valve has five leaflets. Beneath the five commissures are five papillary muscles. The two left-sided papillary muscles are oriented closer together than in a normal heart, and the lateral leaflet is smaller than usual. In addition, the two papillary muscles are often rotated counterclockwise, thus positioning the posterior muscle farther from the septum than normal and the anterior muscle closer to the septum. This papillary muscle arrangement, along with a large anterolateral muscle bundle, can contribute to progressive LVOT obstruction.

13. (A) In partial AVSD, the mitral and tricuspid annuli are separate. Partial AVSD consists of a primum ASD and a “cleft” anterior mitral valve leaflet. Although patients with partial AVSD may be asymptomatic until adulthood, symptoms of excess pulmonary blood flow typically occur in childhood. Tachypnea and poor weight gain occur most commonly when the defect is associated with moderate or severe mitral valve regurgitation or with other hemodynamically significant cardiac anomalies. Patients with a primum ASD usually have earlier and more severe symptoms, including growth failure, than patients with a secundum ASD. Repair of residual/recurrent mitral valve regurgitation or stenosis is the most common reason for reoperation.

In this clinical scenario, surgical correction was required early, suggesting a hemodynamically significant cleft mitral valve. This patient presents with progressive shortness of breath. Physical examination and chest x-ray findings suggest mitral valve regurgitation. Mitral stenosis may also be involved, but the murmur on examination suggests regurgitation is significant. The patient may indeed have pulmonary hypertension, but it would be secondary rather than primary in origin. LVOT obstruction is an important consideration for all forms of AVSD, and it is usually progressive. However, it would be characterized by a systolic ejection-type murmur. Pulmonary stenosis also would have an ejection murmur but would be heard best over the left upper sternal border.

14. (C) In the normal heart, the aortic valve is wedged between the mitral and the tricuspid annuli. In AVSD, the aortic valve is displaced or “sprung” anteriorly. This anterior displacement creates an elongated, so-called gooseneck deformity of the LVOT. LVOT obstruction may occur in all forms of AVSD. It is more frequent when two atrioventricular valve orifices are present than when there is a common orifice. Ten percent of patients with AVSD may require reoperation to relieve LVOT obstruction (while the most common indication for reoperation is left AV valve regurgitation or stenosis). Progressive LVOT obstruction is more common in partial than in complete AVSD. Mechanisms of LVOT obstruction include attachments of superior bridging leaflet to ventricular septum, extension of the anterolateral papillary muscle into the LVOT, discrete fibrous subaortic stenosis, and tissue from an aneurysm of the membranous septum bowing into the LVOT. Obstruction may develop de novo after initial repair of the AVSD and closure of the mitral valve cleft.

15. (D) Right bundle branch block is common and may be due to ventriculotomy or direct injury to the right bundle itself. However, right bundle branch block occurs after a transatrial repair as well. Of the other options, a residual ASD would likely not be the cause of a newly split S₂, a residual VSD would be accompanied by a murmur. Ventilation changes would not result in a newly split S₂.

16. (C) The valve closure sounds in patients with a small VSD are usually normal. Some patients, however, have wide splitting of the second sound. If there is associated pulmonary stenosis or mitral insufficiency in a patient with VSD, these lesions may be suspected when the systolic murmur is transmitted to the upper left sternal border or apex, respectively. Flow across a large (unrestrictive) VSD is limited primarily by relative resistances of the systemic and pulmonary circulations.

Minor anomalies of the tricuspid valve may be acquired secondary to left-to-right shunting across perimembranous defects. These anomalies include redundant septal leaflet tissue that can partially or completely occlude the defect. After VSD repair, the LV mass and volume decrease, but volume decreases at a much greater rate than mass. Finally, patients who develop Eisenmenger physiology typically begin manifesting cyanosis before 2 years of age.

17. (B) Prolapse of one of the aortic valve cusps may occur with outlet or perimembranous VSDs. Patients with outlet defects usually have deficiency of muscular or fibrous support below the aortic valve with herniation of the right coronary leaflet through the VSD. The aortic commissures themselves are usually normal. In contrast, patients with perimembranous VSDs and aortic insufficiency have herniation of the right or much less commonly the noncoronary cusp, have frequent abnormalities of aortic commissures (usually the right/noncoronary), and may have associated infundibular pulmonary stenosis. Echocardiography and angiography can show that the prolapsed aortic leaflet partially closes a moderate to large VSD and limits the left-to-right shunt. The associated aortic valve insufficiency is progressive.

The murmur of an incompetent tricuspid valve or mitral valve would be systolic. The patient is asymptomatic and acyanotic; hence, Eisenmenger physiology is not present. Therefore, RV and LV pressures have not equalized.

18. (B) The relationship of the atrioventricular conduction pathways to VSDs is important to surgical repair. In perimembranous defects, the bundle of His lies in a subendocardial position as it courses along the posterior-inferior margin of the defect. In inlet defects, the bundle of His passes anterosuperiorly to the defect. In muscular VSDs and outlet defects, there is little danger of heart block because the conduction tissue generally is far removed unless these defects extend into the perimembranous area.

19. (A) When signs of necrotizing enterocolitis develop in an infant with significant left-to-right shunting through a PDA, early surgical closure of the ductus arteriosus has significantly reduced mortality. Therefore, if abdominal distention is persistent, increasing residuals before feedings, blood in the stools or gastric aspirate, decreasing bowel sounds, and, particularly, intramural air occurs in association with a significant left-to-right shunt through a PDA, immediate surgical closure is recommended.

20. (A) This vignette describes a child with a hemodynamically significant PDA that has gone unrepaired and now is infected. Streptococcus viridans and Staphylococcus aureus are the most common organisms. Vegetations are almost always seen on the pulmonary artery end of the duct.

21. (B) Postnatal closure of the ductus arteriosus occurs in two phases. The first phase, “functional closure,” occurs within 12 hours after birth. There is contraction and cellular migration of the medial smooth muscle in the wall of the ductus arteriosus that causes the vessel walls to become thick and protrude into the vessel lumen. The second stage usually is completed by 2 to 3 weeks and results from infolding of the endothelium, disruption and fragmentation of the internal elastic lamina, proliferation of the subintimal layers, and hemorrhage and necrosis in the subintimal region. There is connective tissue formation and replacement of muscle fibers with fibrosis with subsequent permanent sealing of the lumen, thus forming the ligamentum arteriosum.

22. (E) Ibuprofen has been evaluated as a possible alternative to indomethacin in preterm infants. Studies have shown a similar rate of ductal closure after ibuprofen treatment with fewer negative effects on renal function, cerebral vasculature, and cerebral blood flow than indomethacin. The risk of intraventricular hemorrhage is equivocal. Of note, using ibuprofen for prophylaxis is associated with increased risk of pulmonary hypertension.

23. (A) Surgical correction of ALCAPA involves direct reimplantation of the origin of the left coronary artery into the aorta and is considered the standard corrective surgical approach in many centers. An alternative approach is the Takeuchi procedure, in which an aortopulmonary window is created and then a tunnel fashioned that directs blood from the aorta to the left coronary ostium.

Because of papillary muscle infarction and dysfunction, significant preoperative mitral insufficiency has been found to be a risk factor for both mortality and need for late mitral valve surgery.

24. (A) A localized weakness of the wall of a sinus of Valsalva leads to aneurysmal bulging. If the aneurysm ruptures, the size of the fistula determines how large the shunt will be, and its site of entry into the heart often determines the specific features. Thus, aneurysmal rupture into the left heart does not produce signs of a left-to-right shunt, whereas rupture into the right heart produces a left-to-right shunt. With a small fistula, there may be only a continuous murmur with its maximal intensity in the third or fourth intercostal space near the sternal edge. If the fistula enters the right atrium, the murmur may be maximal to the right of the sternum. With larger fistulae, there will be a wide pulse pressure, a collapsing pulse, and left ventricular hyperactivity. If the fistula enters the right side, there will be right ventricular hyperactivity as well. A large fistula entering the left ventricle may display a to-and-fro murmur and simulate aortic incompetence. Occasionally, there is only a diastolic murmur in fistulae entering the left ventricle or the high-pressure right ventricle in a neonate.

25. (C) In this anomaly, the left coronary artery arises from the pulmonary artery, usually from the left posterior facing sinus. In fetal life, pressures and oxygen saturations are similar in the aorta and pulmonary artery, so myocardial perfusion is normal. After birth, the pulmonary arteries have low pressures and desaturated blood, which does not bode well for myocardial perfusion. Myocardial ischemia subsequently occurs. Ischemia is worsened with exertion such as feeding or crying. As time passes, infarction of the anterolateral LV free wall occurs. The mitral valve papillary muscles are affected, and mitral regurgitation develops.

Anomalous coronary artery origins from the wrong sinus of Valsalva are generally asymptomatic in infancy. The most common anomaly (a third of all major coronary arterial anomalies) is origin of the left circumflex from the right main coronary artery. This anomaly has no general clinical significance in the absence of intracardiac surgery.

The origin of the left main coronary artery from the right sinus of Valsalva is less common but more important clinically. If the anomalous vessel passes between the aorta and the RVOT, the child is at risk for sudden death during or just after vigorous exercise. In many of these cases, the ostium of the left main coronary artery is slit-like, increasing further the risk.

26. (C) A localized weakness of the wall of a sinus of Valsalva leads to aneurysmal bulging. Localized aneurysms are usually congenital, with thinning just above the annulus at the leaflet hinge. However, aneurysms can follow infective endocarditis. Approximately 75% of patients are male. Approximately 65% of aneurysms are located in the right aortic sinus, 25% in the noncoronary sinus, and 10% in the left aortic sinus. Up to 50% of cases may be associated with VSDs, especially right sinus aneurysms associated with defects of the outlet septum. Aneurysms can rupture into any cardiac chamber. Rupture is most often of the right sinus aneurysm into the right ventricle in the setting of an outlet VSD. Rupture into the pericardium is rare.

27. (E) Central nervous system AVMs manifest symptoms according to their hemodynamic effects. Infants presenting with CHF typically have large AVMs. The most common cerebral AVMs presenting with CHF are located deep (vein of Galen), superficial (pial), or dural. Affected infants have high-output CHF with dilation of all cardiac chambers, feeding arteries, and draining veins. If there is venous obstruction, flow can be restricted through the AVM, so patients may present with venous hypertension or cerebral ischemia.

The prognosis for most patients with large cerebral arterial malformations is grave. If untreated, most newborns (90%) die during the first week of life from intractable CHF or neurologic complications (seizures, intracranial hemorrhage). Those who do survive the neonatal period often suffer profound neurologic morbidity (hydrocephalus, mental retardation, hemorrhage).

28. (C) Most pulmonary AVMs are congenital or associated with HHT. Pulmonary AVMs enlarge as the child grows older. A high proportion (>85%) of patients with multiple pulmonary AVMs have HHT. Overall, 30% to 50% of patients with pulmonary AVMs have HHT.

Patients with pulmonary AVMs generally are hemodynamically stable. In contrast to systemic AVMs, cardiac output is not increased, while pulmonary blood flow and pressures are unchanged. Of note, during cardiac catheterization, the total PVR is normal. That is, resistance within the AVM is low, whereas the resistance in the other lung segments may be elevated.

29. (B) Transcatheter embolization has become the treatment of choice for pulmonary AVMs. Embolization provides persistent relief of hypoxemia, resolution of orthodeoxia, and minimal growth of small remaining AVMs. The embolization procedure is effective for preventing stroke and transient ischemic attacks but does not appear to reduce the risk of brain abscess.

To avoid device embolization (through the AVM to the systemic circulation), transcatheter occlusion of the afferent artery or fistula is usually accomplished using a coil or umbrella rather than liquid adhesive or beads. The goal is to raise the systemic arterial oxygen tension (some authors suggest to 60 mm Hg) by occluding the most significant afferent arteries (generally considered those to be >3 mm in diameter).

30. (C) Large AVMs and large patent ductus arteriosus have similar hemodynamic effects (large extracardiac left-to-right shunts) and thus are indistinguishable in terms of pulse pressure, liver span, cardiothoracic ratio on chest x-ray, and QRS axis on ECG. Diagnostic cardiac catheterization is usually unnecessary, as the diagnosis is suspected by clinical examination and confirmed by noninvasive imaging. When performed, catheterization demonstrates high cardiac output, elevated atrial and ventricular end-diastolic pressures, a widened systemic arterial pulse pressure, and a large difference in the oxygen saturation between the superior and inferior vena cava (higher saturation from the involved area).

31. (B) A barium esophagram that shows an anterior indentation is virtually pathognomonic for a pulmonary artery sling or a tumor. Origin of the left pulmonary artery from the right pulmonary artery, known as a pulmonary artery sling, is a rare anomaly in which the lower trachea is partially surrounded by vascular structures. The left pulmonary artery arises as a very proximal branch of the right and then loops around the trachea. It is the only situation in which a major vascular structure passes between the trachea and esophagus.

Pulmonary sling is frequently associated with complete cartilaginous rings in the distal trachea resulting in tracheal stenosis. It usually appears as an isolated abnormality but can be associated with other congenital cardiac defects, including tetralogy of Fallot.

32. (B) Right aortic arch with mirror-image branching describes an aortic arch that traverses the right mainstem bronchus. The first branch is a left innominate artery that divides into left carotid and left subclavian arteries. The second branch is the right carotid, and the third is the right subclavian. The ductus arteriosus (or ligamentum arteriosum) is usually on the left side and arises from the base of the innominate artery. This lesion typically does not form a vascular ring. However, this arch anomaly is frequently associated with congenital intracardiac disease. The most common association is with TOF, but other conotruncal anomalies may also be seen, as well as DORV. Therefore, an echocardiogram should be considered in this patient to evaluate the intracardiac anatomy.

The patient is asymptomatic at this time, so further workup for a vascular ring (such as swallowing study or bronchoscopy) is not necessary.

33. (A) A vascular ring is an aortic arch anomaly in which the trachea and esophagus are completely surrounded by vascular structures. The clinical picture typically includes respiratory symptoms, especially stridor. Pneumonia, bronchitis, or cough may also be present. Infants may demonstrate a posture of hyperextension of the neck. A common history is that of a 1 to 3 month old with “noisy breathing since birth” who develops more significant respiratory distress in association with an intercurrent upper respiratory infection. Less commonly (and usually in toddlers or older children), the presentation will be swallowing difficulty. Of the listed options, only a right aortic arch with retroesophageal innominate artery and a left PDA complete the ring.

34. (D) Interrupted aortic arch (IAA) is defined as a complete separation of ascending and descending aorta. Celoria and Patton classified IAA into three types: type A if the interruption was distal to the left subclavian artery, type B if between carotid and subclavian arteries, and type C if between carotid arteries. These patients typically present with acute cardiovascular collapse or heart failure after spontaneous closure of the ductus arteriosus in the first days of life.

Absence of all limb pulses suggests a type B interruption with an anomalous subclavian artery. In this situation, both carotid arteries are proximal to the interruption, while both subclavians are distal to the interruption. Strong carotid pulses help to differentiate interrupted arch from critical aortic stenosis in which all pulses are diminished.

35. (A) Right aortic arch with diverticulum of Kommerell is the second most common vascular ring after double aortic arch.

In right aortic arch with mirror-image branching, there usually is no left-sided ductus arteriosus or ligamentum arteriosum and thus no vascular ring. Left aortic arch with retroesophageal right subclavian artery is the most common aortic arch anomaly, but does not form a ring and is usually asymptomatic. Right aortic arch with retroesophageal innominate artery is a very rare abnormality of the aortic arch system. The ductus arteriosus (or ligamentum arteriosum) completes a vascular ring as it connects the left pulmonary artery with the base of the innominate artery. However, it is much less common than right aortic arch with retroesophageal diverticulum of Kommerell.

36. (C) In classic cor triatriatum, a membrane separates the more proximal chamber, which receives the pulmonary veins, from the more distal left atrium, which communicates with the mitral valve. To allow for cardiac output, typically there is a hole in the membrane that ranges from <3 mm to about 1 cm. The distal, true left atrium is in continuity with the left atrial appendage. The fossa ovalis usually is located between the distal left atrial chamber and the right atrium; occasionally, a patent foramen ovale/ASD is present in this area. Right ventricular hypertrophy and dilation are almost invariably found. Right atrial hypertrophy and dilation are present in ˜25% of cases. Hypertrophy and dilation of the right atrium result in tall, broad, oftentimes peaked P waves on ECG.

The prognosis in TAPVC is influenced by the size of the interatrial communication and by the degree of obstruction in anomalous venous pathways. Overall mortality for unrepaired TAPVC is 80% or more at 1 year. Long-term prognosis depends on the state of the pulmonary vascular bed at the time of surgery as well as the patency of the pulmonary venous-left atrial anastomosis. Late arrhythmias may develop in a small number of these patients. Atrial arrhythmias are most common and include sinus bradycardia, atrial flutter, and supraventricular tachycardia. Ventricular rhythm problems are unusual.

Scimitar syndrome describes the chest x-ray findings present in anomalous connection of the right pulmonary veins to the IVC. There is a crescent-like shadow in the right lower lung field; the shape of the shadow resembles a Turkish sword, or scimitar. Frequent coexistent anomalies include hypoplasia of the right lung and chest, mesocardia or dextrocardia, and lung parenchymal abnormalities.

37. (E) A superior sinus venosus defect (also called SVC type) results from deficiency of the common wall between the SVC and the right upper pulmonary vein (RUPV). This defect “unroofs” the RUPV. The unroofed pulmonary vein then drains into the SVC, while its left atrial orifice becomes the interatrial communication. This interatrial communication is not a defect of the atrial septum.

38. (E) The correct catheter course is IVC → right atrium → SVC → innominate vein → vertical vein → anomalous pulmonary venous confluence.

39. (E) In infradiaphragmatic TAPVC, the most common site of obstruction is at the anomalous vessels’ connection with the portal vein or the hepatic veins. By 2D echo, there frequently is seen a dilated venous channel proximal to the site of stenosis. If unobstructed, the anomalous vessel is characterized by a low-velocity, phasic laminar flow pattern with brief flow reversal during atrial systole. Luminal narrowing is associated with flow acceleration and turbulence by color Doppler.

Corrective surgery for the infant or child with TAPVC should be performed as soon as possible. In the sickest infants, the patient’s clinical condition should be optimized, including the cardiorespiratory and metabolic states. When possible, surgery should be done on the basis of echocardiography rather than cardiac catheterization in an effort to lessen the time to operation and therefore reduce mortality.

Balloon atrial septostomy and blade atrial septostomy have been used in the past as palliative procedures. Septostomy delays the definitive procedure and is of little value when an anomalous venous channel is obstructed. Balloon dilation of obstructed anomalous venous channels is usually unsuccessful.

40. (D) The echocardiogram image demonstrates cor triatriatum. Most patients with classic cor triatriatum have onset of symptoms within the first few years of life. However, some patients present in the second or third decade of life. Frequently, these patients will present with a history of dyspnea, frequent respiratory issues including “asthma,” and pneumonia. They often are considered to have primary pulmonary disease.

Untreated cor triatriatum results in pulmonary hypertension. Physical examination findings include a loud pulmonary component of the second heart sound, right ventricular heave, and pulmonary systolic ejection click. A murmur of tricuspid regurgitation may be present. Less often, a diastolic murmur is detected at the mitral area, or a continuous murmur may be heard. Right-sided heart failure is common. Pulmonary rales are heard if pulmonary edema is present.

In the patient with pulmonary edema or right heart failure, the disease frequently is progressive despite maximal medical management. Surgical intervention should be planned as soon as possible. Surgical resection of the cor triatriatum membrane under cardiopulmonary bypass is the effective treatment of choice. When pulmonary edema and right heart failure occur, survival is usually only a matter of months. However, in patients who survive operative correction, the severe pulmonary arterial changes that result in pulmonary hypertension can regress. In these patients, the prognosis seems excellent.

41. (C) Other than partial anomalous pulmonary venous connection (PAPVC) to the right SVC and to the right atrium (sinus venosus defect and malposition of the septum primum, respectively), the most common type of PAPVC is of the left pulmonary veins to the left innominate vein (LIV). The left-sided pulmonary vein(s) connect(s) to the LIV through a persistent early embryonic pathway. The connecting vein (often called a “vertical vein”) between the left pulmonary veins and the LIV may incorrectly be termed a persistent left superior vena cava (LSVC). This term is incorrect both embryologically and anatomically.

Embryologically, the vertical vein represents a persistent early embryonic connection between the splanchnic plexus of the lung buds and the cardinal veins. Anatomically, it is positioned more posteriorly than the LSVC, which is located immediately behind the left atrial appendage. An LSVC usually connects with the coronary sinus, although it may connect with the left atrium when the coronary sinus is unroofed. When a left pulmonary vein drains into the LSVC, the LSVC still should connect with the coronary sinus or with the left atrium.

A secundum atrial septal defect is commonly associated with PAPVC to the LIV. A primum atrial septal defect is very uncommon. Rarely, the atrial septum is intact.

42. (D) Absence of the hepatic segment of the IVC with azygous continuation into the right or left SVC is referred to as an interrupted IVC. Pulmonary AVMs have been known to develop after a classic or bidirectional Glenn anastomosis owing to the exclusion of hepatic venous blood or “hepatic factor” to the lungs. This malformation can develop in one or both lungs if preferential blood flow is present. In the case described in this vignette, there is likely inadequate hepatic venous blood flow to the pulmonary arteries.

43. (B) Congenital malformations of the coronary sinus frequently are associated with arrhythmias. SVT and sudden cardiac death have been reported in a significant percentage of patients with diverticula of the coronary sinus. Patients with diverticula of the coronary sinus usually present with SVT associated with accessory pathways that transverse the diverticulum to form an atrioventricular connection.

44. (D) This patient is a setup for inadequate systemic blood flow, given his tricuspid valve atresia and transposition of the great arteries with a restrictive VSD. He has evidence of systemic underperfusion with acidosis. He requires a stable source of systemic blood flow. Of the given options, only a DKS procedure results in a stable systemic circulation.

45. (E) Uhl anomaly is a congenital cardiac malformation consisting of an almost total absence of the RV myocardium. Cyanosis and hepatomegaly are often present, as is jugular venous distention. The precordium usually is quiet, and peripheral pulses are diminished. The heart tones are decreased. A pansystolic murmur of tricuspid insufficiency may be present, but patients may have no murmurs or other nonspecific murmurs present.

ECG usually shows prominent P waves and diminished QRS amplitude, especially in the right precordial leads. The chest x-ray demonstrates cardiomegaly with normal to diminished pulmonary vascularity (which can appear similar to Ebstein anomaly of the tricuspid valve).

Echocardiography demonstrates marked dilation of the right-sided cardiac chambers. An important finding is the presence of the tricuspid valve leaflets arising appropriately from the annulus, differentiating this lesion from Ebstein anomaly.

At cardiac catheterization, similar pressure wave contours are obtained from the pulmonary artery, right ventricle, and right atrium. The right atrial a wave is dominant. Endocardial potentials, if recorded during catheterization, show normal transition between the ventricular and atrial complexes, helping to rule out Ebstein anomaly.

Most patients die in infancy or childhood. The typical pathologic finding is the markedly dilated, “parchment-like” right ventricle. Histologically, the endocardium is thickened, and there are few if any true myocardial cells in the right ventricular free wall. The tricuspid valve arises normally from a dilated valve annulus and may be dysplastic, but is not displaced into the right ventricular cavity.

46. (C) In patients with relatively normal cardiac output, classification of severity of pulmonary stenosis routinely is based on measurements of RV pressure and valve gradient. Mild stenosis is characterized by an RV pressure less than half the LV pressure or a peak valve gradient <35 mm Hg to 40 mm Hg. In moderate stenosis, the RV pressure is ˜50% to 75% of the LV pressure, or the peak gradient is ˜40 mm Hg to 60 mm Hg. Severe stenosis is defined as an RV pressure ≥75% of the LV pressure or a peak gradient >60 mm Hg to 70 mm Hg.

In this case, TR velocity predicts an RV-to-RA pressure gradient of 49 mm Hg, or an RV systolic pressure of 55 mm Hg. Using the modified Bernoulli equation 4(V₂² – V₁²), the peak gradient across the pulmonary valve is 4(16 – 4) or 48 mm Hg. Both of these measurements indicate moderate pulmonary valve stenosis.

49. (D) In the setting of unilateral branch pulmonary artery stenosis without a significant left-to-right shunt, resting RV systolic pressure remains normal. The contralateral pulmonary artery accommodates the cardiac output without an increase in pressure. Because flow to the stenotic side is lower than normal, the severity of obstruction may be underestimated by systolic pressure difference estimations (though the diastolic pressure difference is proportional to the severity of obstruction).

The protocol for angioplasty consists of positioning a balloon dilation catheter across the stenotic segment of the pulmonary artery. In contrast to pulmonary valve dilation, the balloon diameter should be three to four times the narrowest pulmonary artery segment.

Percutaneous balloon angioplasty of peripheral pulmonary artery stenosis has a lower success rate than pulmonary valvuloplasty. The overall acute success rate for branch PA angioplasty is ˜50% to 60%. The rate of recurrent stenosis has been 15% to 20% in short- to mid-term follow-up.

50. (C) It is important to confirm the coronary circulation in patients with pulmonary atresia with intact ventricular septum before proceeding with an intervention. “Right ventricular-dependent coronary artery circulation” describes the situation whereby the myocardium is supplied by blood that originates in the RV at systemic or supersystemic systolic pressure and supplies the myocardium in a retrograde fashion. Myocardial ischemia, infarction, and death may result if significant ventriculo-coronary connections are present and the right ventricular pressure is reduced secondary to an intervention.

In the normal circulation, the aortic diastolic pressure primarily drives coronary blood flow. Factors that reduce aortic diastolic pressure (or shorten diastole) will compromise coronary blood flow. The presence of ventriculo-coronary artery connections may result in coronary artery stenosis and/or interruption. In this case, aortic diastolic pressure may not be sufficient to drive coronary blood flow; elevated RV pressures are necessary. Interference with blood flow into the RV or other reduction of RV systolic pressure has deleterious effects.

51. (E) Transcatheter perforation of the atretic pulmonary valve with subsequent balloon dilation is an alternative to surgical valvotomy. The ideal patient (lowest risk) would have a tripartite right ventricle of near-normal size with valvar pulmonary atresia and a well-developed pulmonary arterial circulation. There would not be RV-depending coronary circulation.

In general, the smallest RVs are associated with the most ventriculo-coronary connections. Unipartite or bipartite ventricles are much more likely to have ventriculo-coronary communications. Using the convention of the tricuspid Z value, data from the CHSS demonstrated a positive correlation with ventriculo-coronary connections—a more negative tricuspid Z value correlates with the presence of ventriculocoronary connections.

52. (A) This patient demonstrates evidence of RV-dependent coronary circulation. Therefore, decompression of the RV is not warranted, eliminating an RV-PA conduit or pulmonary valvotomy.

53. (D) The angiogram demonstrates evidence of RV-dependent coronary circulation in the inferior distribution. Therefore, he would exhibit evidence of myocardial ischemia in an inferior distribution, including ST elevation in leads II, III, and aVF.

54. (C) Despite the lack of evidence of RV-dependent coronary circulation by echocardiography, cardiac catheterization is still necessary to rule out such circulation. MRI does not have a role in the preoperative management of a 4-day-old infant. Biopsy is not indicated.

55. (E) These images demonstrate pulmonary atresia with intact ventricular septum. Ventriculo-coronary connections are observed in ˜45%, but <10% of patients are considered to have wholly RV-dependent coronary circulation (CHSS database). Confluent pulmonary arteries usually are supplied by a left-sided ductus arteriosus. A main pulmonary artery is almost always present. Rarely, nonconfluent pulmonary arteries are supported by bilateral ductus arteriosus or aortopulmonary collaterals. Some patients with this disease have all three RV components present; in others, the RV is extremely underdeveloped and may have an inlet only. There is no known gender predilection.

56. (E) For patients whose pulmonary artery anatomy appears amenable to reconstruction, procedures leading to complete repair are indicated. Connecting the RV to the central pulmonary artery using a conduit is performed; this may promote growth of the central pulmonary arteries. Unifocalization procedures are performed to incorporate the maximum number of pulmonary artery segments into the eventual RV outflow reconstruction. The ultimate goal is complete repair (closure of all septal defects, interruption of all extracardiac sources of pulmonary arterial blood flow, and incorporation of at least 14 pulmonary arterial segments in a connection to the right ventricle).

At the end of a full repair, the central pulmonary artery size should be at least 50% of normal size. At the end of the operation, the RV pressure should be ≤70% than that measured in the LV. If higher, the VSD should be reopened.

57. (D) At the end of the operation, the right ventricular pressure should be ≤70% of the left ventricle. If higher, the VSD should be reopened.

58. (C) This patient has an estimated RVSP of >50 mm Hg, based on the modified Bernoulli equation. Given that her systemic BP is 65 mm Hg, her VSD should be reopened. RV systolic pressure at the conclusion of the operation should be <70% of LV systolic pressure.

59. (C) In PA-VSD, the blood supply to the lungs is entirely from the systemic arterial circulation. These include the ductus arteriosus, multiple systemic-to-pulmonary collateral arteries, occasionally a coronary artery, and plexuses of bronchial or pleural arteries. Ductal and collateral sources may be present in the same patient but rarely in the same lung.

The caliber of the central pulmonary arteries appears to be directly related to the amount of blood flow present through that segment. When the ductus or collateral arteries connect proximally to the central pulmonary arteries (as in this patient), the pulmonary arteries may be mildly hypoplastic or even normal in size. When multiple collateral arteries are present more distally, the central pulmonary arteries are usually hypoplastic.

60. (A) In pulmonary atresia with VSD, the sinus node is normal. The AV node occupies its normal position within the triangle of Koch. The nonbranching proximal portion of the His bundle penetrates the central fibrous body and lies along the left ventricular aspect of the posteroinferior rim of the VSD.

61. (E) Hypercyanotic spells constitute a medical, and possibly surgical, emergency. Treatment is directed toward lowering impedance to pulmonary flow and further increasing systemic vascular resistance. Typical treatment includes administration of supplemental oxygen, volume expansion, β-blockade, and sedation with morphine or ketamine. If needed, vasopressors (such as phenylephrine) can be used to increase systemic vascular resistance and decrease the relative ratio between pulmonary and systemic resistance. Occasionally, emergent surgical palliation or repair is required.

To prevent such spells, dehydration should be avoided; hence, making the patient NPO after midnight and starting an IV at 7:00 am or performing phlebotomy to decrease Hgb to <14 before starting the IV are incorrect. Using a general anesthesia-inducing agent that decreases systemic vascular resistance more than PVR is the inverse of what is advisable. Starting an esmolol drip as soon as the procedure starts is not a bad choice, per se, because β-blockade is used to treat a hypercyanotic spell. However, making the patient NPO after midnight, starting IV fluid when NPO starts, and using a topical anesthetic such as EMLA before attempting vascular access is better because such measures can help prevent a spell, rather than treat a spell once it has started.

62. (E) Waterston shunts (anastomosis of the ascending aorta to the right pulmonary artery) or Potts shunts (descending aorta to the left pulmonary artery) may result in pulmonary artery distortion with consequent inconsistent transmission of flow and pressure to the pulmonary arterial bed. Pulmonary arterial stenosis and/or pulmonary vascular disease preclude routine use of these palliative procedures.

The catheterization data demonstrate a significant gradient between the MPA and the RPA. The patient may or may not benefit from sildenafil; further testing with inhaled NO would help make such a determination. She does not have evidence of a left-to-right shunt based upon her SpO₂ measurements. At this point, she does not have evidence of RV-PA conduit stenosis as the RV-to-MPA systolic gradient is <10 mm Hg. Her dyspnea on exertion more likely is due to her pulmonary vascular disease than her mild LV diastolic dysfunction (LVEDP = 10 mm Hg).

63. (E) Some newborns with TOF with absent pulmonary valve may be asymptomatic with only mild cyanosis and no findings of heart failure. Patients with TOF and absent pulmonary valve usually have some degree of RVOT obstruction, caused predominantly by a ring of tissue at the level where the pulmonary valve leaflets would be expected rather than the infundibulum. As PVR drops in early infancy, a net left-to-right shunt can develop with pathophysiology of a VSD. These patients may require minimal medical intervention and undergo elective surgical correction at a later age. Other newborns can present with respiratory failure. In the most serious cases, central bronchial compression from massively dilated pulmonary arteries can result in respiratory failure despite conventional mechanical ventilation. In this case, respiratory distress may be improved by placing the patient prone to suspend the pulmonary arteries off the airways.

64. (D) This patient demonstrates evidence of critically restricted antegrade flow to the lungs. Given a prenatal diagnosis of TOF, it is reasonable at this point to start prostaglandin to reopen the ductus arteriosus. Once he is stabilized, he can be considered for either total repair or a systemic-to-pulmonary shunt. While most newborns with TOF do not have ductal-dependent pulmonary blood flow and may be followed without specific early intervention, this patient demonstrates that he is “ductal dependent.” PGE1 should be started without delay. Then other studies, such as echocardiogram, can be performed. He should not go to surgery before attempts at medical stabilization have been made.

65. (C) All patients with TOF demonstrate anterior and cephalad deviation of the outlet septum. The degree and nature of this deviation determine the severity of subpulmonic obstruction, the size of the VSD, and the degree of aortic override. In virtually all patients with severe infundibular obstruction, there is an associated large, nonrestrictive VSD and a prominent overriding aorta. In this case, it is very uncommon to have a restrictive VSD. Among other findings, a large conal branch, or accessory left anterior descending artery, is seen in ≤15% of hearts. A left SVC is found in ˜10% of patients.

66. (C) A truly continuous murmur is uncommon in truncus arteriosus. When present, it usually suggests pulmonary artery ostial stenosis. Continuous murmurs are common in patients with PA/VSD. Patients with PA/VSD can have either a patent ductus arteriosus or systemic collateral arteries to the pulmonary arteries. Because the differential diagnosis of truncus arteriosus includes this lesion, a continuous murmur is strongly suggestive of pulmonary atresia rather than of truncus arteriosus.