Congenital Cardiac Malformations
M. Eric Ferguson
Benjamin W. Eidem
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1. A 4-month-old girl is referred to you because of a cardiac murmur. She appears jaundiced. She has a grade 2 to 3/6 systolic ejection murmur along the left upper sternal border that radiates to the back bilaterally. She has prominent facial features including a broad forehead and pointed chin. Her mother has similar features. A defect in which of the following genes would most likely explain her clinical findings?
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. A 28-year-old woman develops severe rubella infection late in the second month of pregnancy. The fetus is at increased risk for which congenital heart defect?
A. Complex heterotaxy
B. Ebstein anomaly
C. Coarctation of the aorta
D. d-Transposition of the great arteries (d-TGA)
E. Valvar and supravalvar pulmonary stenosis
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. A 31-year-old primigravid woman drinks three cups of coffee daily. She is otherwise healthy. The fetus is at increased risk for which congenital heart defect?
A. Tetralogy of Fallot (TOF)
B. Tricuspid atresia
C. Patent foramen ovale
D. Secundum atrial septal defect
E. No increased risk of cardiac defects
3. (E) Caffeine intake during pregnancy has not been shown to result in an increased risk of congenital heart disease in the fetus.
4. Which of the following defects is most likely to occur in a newborn whose mother had phenylketonuria?
A. Ebstein anomaly
B. Tricuspid atresia
C. Coarctation of the aorta
D. Anomalous pulmonary venous return
E. Right aortic arch
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. You are asked to evaluate a 2-year-old boy for a cardiac murmur. You note that the child, for a 2 year old, is quite friendly and has stellate irises, a long philtrum, depressed nasal bridge, prominent lower lip, and enamel hypoplasia. There is a grade 3/6 systolic ejection murmur and no click. Which of the following chromosomal deletions is most likely in this patient?
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. A 4-month-old boy develops tachypnea and poor feeding. On examination, the blood pressure in the right arm is 110/60 mm Hg, in the left arm 105/60 mm Hg, and in the right leg 108/60 mm Hg. An echocardiogram demonstrates increased left ventricular (LV) wall thickness, moderate supravalvar aortic stenosis with estimated mean outflow gradient of 44 mm Hg, and mild supravalvar pulmonary stenosis. The aortic and pulmonary valves appear normal. The estimated LV ejection fraction (EF) is 20% with evidence of inferior wall hypokinesis. Which of the following is the most likely diagnosis in this patient?
A. Velocardiofacial syndrome
B. Down syndrome
C. Williams syndrome
D. Rheumatic heart disease
E. Coarctation of the aorta
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. You are consulted to assess a small-for-gestational-age newborn with a heart murmur. Dysmorphic features include microcephaly, microphthalmia, short palpebral fissures, micrognathia, a prominent occiput, short sternum, and small nipples. The hands are clenched with overlapping fingers, and the feet have a convex shape. Which of the following statements is correct regarding this clinical scenario?
A. Trisomy 13 is the most likely clinical diagnosis
B. Associated congenital heart disease (CHD) occurs in ˜50% of patients
D. Most patients survive well into the second decade of life without surgery
E. If corrective cardiac surgery is performed successfully, the risk of death is decreased 10-fold
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. An infant presents in the newborn nursery with feeding difficulty and is noted to have cleft palate, hypocalcemia, and lymphopenia. FISH testing is positive for a 22q11 deletion. Among the following, what is his echocardiogram most likely to demonstrate?
A. Ebstein anomaly of the tricuspid valve
B. Pulmonary atresia + intact ventricular septum (IVS)
C. Interruption of aortic arch between the left common carotid and left subclavian arteries
D. Left ventricular diverticulum
E. Double-outlet right atrium
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. You are seeing a female patient for a chief complaint of dyspnea with exertion. You note in her medical chart that she has a history of a large secundum atrial septal defect (ASD) that apparently went unrepaired. She last saw a physician at age 10 years, where the defect was noted to be 18 mm by echocardiography. The patient is now 31 years old. She has not had any cardiovascular interventions in the interim. You listen and fail to appreciate a widely split S2. In fact, you think the split is narrow and P2 is loud. There is a very short systolic murmur over the left upper sternal border (LUSB). There is no diastolic murmur. What is the most likely cause of the physical findings?
A. Spontaneous closure of the defect
B. Severe mitral valve regurgitation
C. Nonsustained ventricular tachycardia
D. Left ventricular diastolic dysfunction
E. Significant pulmonary hypertension
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. A 19-year-old male patient is found by echocardiogram to have a large sinus venosus defect with partial anomalous pulmonary venous connection with drainage of the right upper and middle pulmonary veins to the superior vena cava. The right ventricle appears severely dilated with moderately decreased function. The ventricular septum appears flattened throughout the cardiac cycle. The tricuspid valve does not leak. There is trace pulmonary insufficiency. What is your recommendation to the patient?
A. Dismiss from follow-up as there is nothing to be done
B. Begin propranolol immediately
C. Start IV epoprostenol
D. Cardiac catheterization with pulmonary vascular reactivity testing
E. Counsel that there is little to do at this point, as he is past the point of medical benefit
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. In a patient with typical auscultatory findings of an atrial septal defect (ASD) and a P-wave axis of <30 degrees on the electrocardiogram, one should think immediately of which of the following types of atrial septal defect?
A. Unroofed coronary sinus
B. Sinus venosus
E. Patent foramen ovale
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. Which of the following papillary muscle arrangements are seen most commonly with complete atrioventricular canal (septal) defect (AVCD, or AVSD)?
A. The papillary muscles are closer together, the anterior muscle is closer to the septum than normal, and the posterior muscle is farther from the septum than normal
B. The papillary muscles are closer together, the anterior muscle is farther from the septum than normal, and the posterior muscle is closer to the septum than normal
C. The papillary muscles are closer together and positioned clockwise from their normal location
D. The papillary muscles are farther apart, the anterior muscle is closer to the septum than normal, and the posterior muscle is farther from the septum than normal
E. The papillary muscles are farther apart, the anterior muscle is farther from the septum than normal, and the posterior muscle is closer to the septum than normal
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 17-year-old male who underwent complete repair of a partial atrioventricular septal defect (AVSD) at 15 months of age presents with progressive shortness of breath. He has a grade 3/6 holosystolic murmur that is loudest over the apex and is less prominent with Valsalva maneuver. Chest x-ray reveals mild cardiomegaly and mildly increased pulmonary vascularity. Which of the following is the most likely cause of these symptoms?
A. Mitral regurgitation
B. Primary pulmonary hypertension
C. Left ventricular outflow tract obstruction
D. Mitral stenosis
E. Pulmonary valve stenosis
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.
A. Obstruction may be due to displacement of the left atrioventricular (AV) valve annulus, resulting in shortening and narrowing of the LVOT
D. Preoperative LVOT obstruction is often progressive, while postoperative obstruction is frequently static
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. An 18-month-old boy undergoes operative repair of a moderate-sized ASD and moderate-sized mid-muscular ventricular septal defect (VSD). His preoperative chest x-ray revealed borderline cardiomegaly and an ECG at the same time was normal. He remains intubated on post-op day 2, at which time you note a new finding of a widely split S2 with no murmur. Which of the following is the most likely reason for your findings?
A. Residual ASD
B. Residual VSD
C. Postoperative decrease in pulmonary artery pressure
D. Right bundle branch block
E. Mechanical ventilation
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. Which of the following statements is true regarding VSD?
A. Flow across a large (unrestrictive) VSD is limited primarily by the size of the defect
B. Frequently, supracristal defects are partially or completely occluded by redundant tricuspid valve tissue
C. Prominent S2 splitting is occasionally heard with a small VSD
E. Patients who develop Eisenmenger physiology typically first manifest cyanosis between ages 4 and 6 years
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. You are seeing a 19-year-old female who was diagnosed at age 6 months with a moderate-sized, isolated perimembranous VSD with outlet extension. The patient was then lost to cardiology follow-up. The patient presents for evaluation of a murmur that was noted during her required physical for her new job. She is asymptomatic and plays golf 2 to 3 times per week. On examination, she is acyanotic. There is a grade 2/6 systolic murmur over right upper sternal border and a grade 3/4 highpitched decrescendo diastolic murmur at the left sternal border. What is the most likely explanation for the murmur?
A. Prolapse of the left aortic cusp has closed the VSD, and the aortic valve is insufficient
B. Prolapse of the right aortic cusp has closed the VSD, and the aortic valve is insufficient
C. Prolapse of the septal leaflet of the tricuspid valve has closed the VSD, and the tricuspid valve is insufficient
D. Right and left ventricular pressures have equalized, and new pulmonary insufficiency has developed
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.
18. What is the relationship of the bundle of His to an inlet VSD?
A. The bundle passes posterior-inferiorly to the defect
B. The bundle passes anterior-superiorly to the defect
C. The bundle courses caudally around the defect
D. The bundle courses through the right AV groove
E. The bundle passes laterally to the defect through the left ventricle
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 28-week preemie develops persistent abdominal distention, increasing residuals before feedings, blood in the stools, and decreasing bowel sounds. Abdominal x-ray reveals evidence of intramural air in the right lower quadrant. The patient has bounding pulses, and an echocardiogram confirms the presence of a hemodynamically significant patent ductus arteriosus (PDA). What is the best next step in management?
A. Referral to surgery for immediate surgical closure
B. Percutaneous closure of PDA with occluding coil
C. Trial of indomethacin
D. Trial of ibuprofen
E. Do nothing
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. You see an 8-year-old child who presents for evaluation of a cardiac murmur. As an infant, he had poor feeding, irritability, and tachypnea. Weight gain was slow. The symptoms gradually resolved after age 3 to 4 months, and he has grown steadily along the third percentile since then. He tires more easily than his peers. He has progressive myalgias, arthralgias, headache, and general malaise. Fever is relapsing and low grade, and his parents report marked diminution in appetite.
On examination, peripheral pulses are full and bounding. The precordium is hyperdynamic, and there is a thrusting apical impulse. A systolic thrill is palpable at the upper left sternal border. S1 and S2 are difficult to hear because they are masked by a loud continuous murmur. The murmur is intense and is heard throughout the precordium as well as posteriorly. It has a harsh quality with low-frequency components, and eddy sounds that vary from beat to beat give it a machinery quality. A third heart sound is heard at the apex. Blood cultures are positive for Streptococcus viridans. His CXR is shown in Figure 2.1.
Which of the following statements is most likely to be true in this clinical setting?
A. Vegetation is likely, and it will be seen on the pulmonary arterial (PA) end of the ductus arteriosus
B. Vegetation is likely, and it will be seen on the aortic end of the ductus
C. Streptococcus viridans is very unlikely to cause endocarditis in this setting
D. Abscess is much more common than vegetation in this setting
E. Vegetation is unlikely but, if present, would be seen on the aortic end of the ductus
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. Which of the following events is most responsible for early, functional closure of the ductus arteriosus?
A. Hemorrhage and necrosis in the subintimal region
B. Medial smooth muscle cell migration in the wall of the ductus
C. Equalization of pulmonary and systemic vascular resistance
D. Infolding of the endothelium
E. Thinning of the intimal layer
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. What is the theoretical benefit of ibuprofen over indomethacin for closure of PDA in premature infants?
A. Decreased risk of intraventricular hemorrhage
B. Decreased risk of pulmonary hypertension
C. Decreased risk of gastrointestinal bleeding
D. Greater rate of ductal closure
E. Less effect on cerebral blood flow
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 2-week-old infant is found to have anomalous left coronary artery from the pulmonary artery (ALCAPA). Surgical correction is planned. What preoperative comorbidity has been found to be a risk factor for mortality and for late reoperation?
A. Mitral insufficiency
B. Tricuspid insufficiency
C. Aortic valve insufficiency
D. Pulmonary valve insufficiency
E. Patent foramen ovale
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. You examine a 17-year-old male with a 2-year history of progressive dyspnea on exertion and 2 months of orthopnea. Vital signs: pulse 80 beats per minute, BP 118/44 mm Hg, respiratory rate 24 breaths per minute. Physical examination reveals a lift along the left sternal border and a continuous murmur with maximal intensity in the third to fourth intercostal space near the right sternal edge. On the basis of the available information, of the following diagnoses, which is most likely?
A. Sinus of Valsalva fistula from the aorta to the right atrium
B. Sinus of Valsalva fistula from the aorta to the left atrium
C. Anomalous left coronary artery from the pulmonary artery
D. Patent ductus arteriosus
E. Severe isolated aortic regurgitation
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. A 3-week-old infant has had several episodes of acute onset of agitation and crying. During these episodes, the baby is inconsolable. On examination, there is a high-frequency systolic murmur audible at the apex with radiation to the left axilla. Which of the following coronary artery anomalies most likely would be responsible for these symptoms?
A. Anomalous origin of right coronary artery from left sinus of Valsalva
B. Anomalous origin of left main coronary artery from right sinus of Valsalva
C. Anomalous origin of left coronary artery from the pulmonary artery
D. Anomalous origin of left anterior descending artery from the right main coronary artery
E. Origin of left circumflex coronary artery from the right main coronary artery
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. Which of the following is true regarding aneurysms of the sinus of Valsalva?
A. The most common location is the noncoronary sinus
B. There is no gender predilection for aneurysm formation
C. Concomitant VSD is seen up to 50% of the time
D. The most common site of rupture is into the left atrium
E. Most VSDs seen with coronary sinus aneurysms are paramembranous
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. A neonate presents at birth with high-output cardiac failure secondary to a cerebral arteriovenous malformation (AVM). If left untreated, what is the approximate risk of mortality during the first week of life?
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. Which of the following is true regarding pulmonary AVM?
B. In patients with pulmonary AVM, cardiac output typically is twice that of normal
C. If there are multiple pulmonary AVMs, there is a >80% chance of the patient having HHT
D. Patients with pulmonary AVMs typically are hemodynamically unstable and require significant respiratory support in infancy
E. Most pulmonary AVMs in children are acquired
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. Which of the following statements is correct regarding transcatheter embolization of pulmonary AVM?
A. To avoid device embolization, liquid adhesive is more effective than coil device closure
B. Embolization effectively prevents strokes and transient ischemic attacks, but not brain abscesses
C. Embolization effectively prevents brain abscess but does not prevent strokes
D. Greatest success is achieved by decreasing systemic arterial oxygen tension to <50 mm Hg
E. Embolization provides persistent relief of desaturation but not of orthodeoxia
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).
A. Pulse pressure as determined by sphygmomanometry
B. Cardiothoracic ratio on plain chest x-ray
C. Systemic vein oxygen saturation measurements obtained during cardiac catheterization
D. QRS axis on electrocardiogram
E. Liver span by physical examination
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. An 11-year-old boy is evaluated for swallowing difficulty and moderate exercise intolerance. A barium esophagram shows evidence of anterior indentation, and pulmonary function testing shows evidence of obstruction. What is the most likely diagnosis?
A. Retroesophageal left subclavian artery
B. Pulmonary artery sling
C. Tracheoesophageal fistula
D. Innominate artery compression of the trachea
E. Retroesophageal fistula of Phillips
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. A CT scan is done to assess a neck mass in a 3-year-old patient with a history of murmur but no prior cardiac history. This patient has no trouble swallowing and has no history of respiratory problems. The scan incidentally showed a right aortic arch with mirror-image branching. What additional action is warranted?
A. Barium swallow
D. Surgical referral
E. No further action needed
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. Which of the following typically results in a vascular ring?
A. Right aortic arch with retroesophageal innominate artery, left patent ductus arteriosus
B. Right aortic arch, retroesophageal left subclavian artery, no patent ductus arteriosus
C. Right aortic arch with mirror-image branching, right ligamentum arteriosus
D. Left aortic arch with cervical origin of right subclavian artery
E. Left aortic arch with retroesophageal right subclavian artery
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. An infant presents with acute cardiovascular collapse on day 3 of life. Physical examination reveals absence of all limb pulses with strong carotid pulses bilaterally. Echocardiography is most likely to reveal which of the following?
A. Critical aortic stenosis
B. Interruption of the aortic arch, type A, with anomalous subclavian artery
C. Interruption of the aortic arch, type B
D. Interruption of the aortic arch type B with anomalous subclavian artery
E. Right aortic arch with retroesophageal diverticulum of Kommerell
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 5-month-old girl presents with stridor and wheezing since birth. She has been treated with albuterol and inhaled steroids without any improvement. Her parents have noticed that she has been coughing and gagging since starting baby foods 2 weeks prior. Which of the following diagnoses is most likely?
A. Right aortic arch with retroesophageal diverticulum of Kommerell
B. Left aortic arch with retroesophageal diverticulum of Kommerell
C. Right aortic arch with mirror-image branching
D. Left aortic arch with retroesophageal right subclavian artery
E. Right aortic arch with retroesophageal innominate artery
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. Which of the following statements is true regarding anomalies of pulmonary venous return?
A. An untreated infant born with total anomalous pulmonary venous connection (TAPVC) has a 50% chance of surviving until the age of 1 year
B. The cardiothymic silhouette tends to be shifted leftward in Scimitar syndrome
C. Patients with cor triatriatum have enlargement of the right atrium and right ventricle
D. Normal P-wave size (<2.5 mm) on ECG effectively rules out cor triatriatum
E. Ventricular arrhythmias are common following TAPVC repair
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. A 3-year-old asymptomatic boy has a 2/6 systolic ejection murmur at the left upper sternal border and fixed splitting of S2. An echocardiogram reveals a sinus venosus ASD. This defect results from which of the following?
A. Deficiency of septum primum
B. Deficiency of septum secundum
C. Excessive resorption of septum primum
D. Anomalous insertion of the superior pulmonary vein
E. Deficiency of the common wall of the superior vena cava and the pulmonary vein
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. What is the catheter course in Figure 2.2?
A. Aorta → right aortic arch → innominate artery → BT shunt → RPA
B. Aorta → right aortic arch → right sinus of Valsalva
39. A newborn is diagnosed with infradiaphragmatic TAPVC to the portal vein. Echocardiography demonstrates high-velocity, continuous, nonphasic venous flow in the anomalous vein. PGE1 has been started. The cardiorespiratory and metabolic states have been optimized. What is the best immediate plan of action?
A. Supportive therapy for 24 to 48 hours to allow PA pressures to fall before operation
B. Bedside balloon atrial septostomy
C. Cardiac catheterization to determine pulmonary vascular resistance (PVR) and to perform blade atrial septostomy if needed
D. Balloon dilation +/- stent placement in anomalous pulmonary vein
E. Immediate corrective surgery
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. A 19-year-old female presents with a several-month history of worsening breathlessness. Past medical history is significant for five episodes of pneumonia over her lifetime. Chronic medications include inhaled fluticasone, budesonide, and montelukast. She carries a rescue inhaler of albuterol. Physical examination reveals an RV heave, loud P2, and pulmonary systolic ejection click. There is a soft, blowing systolic murmur along the left sternal border. Echocardiography reveals the following (Figure 2.3):
What is the most correct statement about this condition?
A. Surgical correction is universally futile
B. Medical management offers a better chance of 20-year survival than operative correction
C. Perioperative risk is low
D. In patients who survive operative correction, prognosis is excellent
E. Atrial fibrillation is common
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. Which of the following statements is correct regarding anomalous drainage of the left pulmonary veins to the left innominate vein (LIV)?
A. The left lung drains typically by a left SVC
B. A primum ASD is common
C. The vertical vein represents a persistent embryologic connection between the splanchnic plexus of the lung buds and the cardinal veins
D. This is a normal variant and found in 0.5% of the general population
E. This condition has never been described
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.
42. A 3-year-old child has complex single ventricle, bilateral superior vena cavae, and interrupted IVC with azygous continuation to the right SVC. At operation, he has construction of bilateral bidirectional superior vena caval-pulmonary anastomoses. Two months postoperatively his systemic arterial blood oxygen saturation is 87%, and he is doing well. Six months postoperatively his saturation is 82%, and he is doing well. Two years postoperatively his saturation is 75%, and he is a bit more fatigued. Which of the following factors, unique to the operation he had, contributes the most to his progressive desaturation?
A. Increased coronary sinus drainage
B. Increased pulmonary arteriolar resistance
D. Pulmonary arteriovenous fistulae
E. Decreased chest wall compliance
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. An 8-year-old girl with palpitations has an echocardiogram that demonstrates an outpouching originating in the coronary sinus that has a distinct neck and extends behind the LV. What is the most likely source of her palpitations?
A. RVOT-origin ventricular tachycardia
B. Accessory pathway-mediated SVT
C. AV nodal reentry tachycardia
D. Torsades de pointes
E. Brugada syndrome
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. A 14-day-old infant presents with irritability. He has been eating poorly due to tachypnea (RR = 80s) and he is 15% below his birthweight of 3,216 g. Physical examination reveals tachypnea and a loud systolic murmur over his entire precordium. There is a soft low-pitched diastolic murmur at the apex. Distal pulses are slightly diminished. An ABG demonstrates pH = 7.27, pCO2 = 31, HCO3 = 16 on room air. Echocardiogram reveals tricuspid atresia, d-TGA, and a moderately restrictive VSD. His aortic arch is moderately hypoplastic, although there is no evidence of a definite posterior shelf at the isthmus. Of the following procedures, what is the best initial surgical palliation option?
A. Modified Blalock-Taussig (BT) shunt only
B. PA banding only
C. Bidirectional cavopulmonary anastomosis
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. Which of the following features are more specific for Uhl anomaly than Ebstein anomaly?
A. The presence of significant cyanosis on physical examination
B. Large P waves and diminished right ventricular voltages on ECG
C. Thin appearing, dysfunctional RV myocardium on echocardiography
E. Ventricular endocardial potentials recorded past the expected anatomic tricuspid valve annulus during electrophysiologic assessment
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. An 11-year-old boy with a history of pulmonary stenosis presents for evaluation. His blood pressure at rest is 100/70 mm Hg. Echocardiography reveals normal inspiratory collapse of his IVC. The following Doppler-derived velocities are obtained (at rest):
Tricuspid regurgitation (CW) = 3.5 m/s
Infundibulum (PW) = 2 m/s
RVOT (CW) = 4 m/s
Assume RA pressure is 6 mm Hg. Using traditionally accepted Doppler-derived criteria to determine severity, what degree of pulmonary stenosis is present in this patient?
E. Not enough information provided
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.
The following clinical scenario pertains to Questions 47 and 48:
A 1-day-old term newborn is admitted to the NICU with cyanosis and a murmur. He is diagnosed with critical pulmonary stenosis and a moderate-sized PDA. Percutaneous pulmonary valvotomy is performed. Cardiac hemodynamics obtained during the catheterization are shown in Table 2.1.
TABLE 2.1 Cardiac Hemodynamics Obtained During Catheterization
That night, the baby continues to have low oxygen saturations in the mid-80s despite being mechanically ventilated and on PGE1. On examination, there is a grade 4/6 late-peaking harsh systolic murmur at the left upper sternal border, which is increased in intensity from his admission exam, and a new, soft diastolic murmur. Blood pressure is 52/24 mm Hg. Blood gas reveals a base deficit of -2.
47. Which of the following would be the next best step?
A. Urgent repeat percutaneous valvotomy
B. Urgent open pulmonary valvotomy
C. STAT echocardiogram
D. Increase the PGE dosage
E. Continued close observation
47. (E) If discontinuation of prostaglandin E1 and subsequent ductal constriction are not tolerated immediately after valvuloplasty, these infants can be maintained on prostaglandin for 2 to 3 weeks while intermittently assessing whether constriction of the ductus is tolerated with O2 saturations remaining ≥70%. Neonates who immediately remain cyanotic following valvuloplasty often demonstrate improvement over weeks to months as RV compliance improves and the atrial right-to-left shunt decreases. Ultimately, those in whom a shunt was created can undergo shunt closure either surgically or by transcatheter techniques.
48. Which of the following is the most likely underlying cause of his desaturation?
A. Pulmonary vein stenosis
B. Infundibular RVOT obstruction
C. Right-to-left shunting across the PDA
D. Undiagnosed VSD
E. Severe pulmonary regurgitation
48. (B) As a result of pulmonary valve stenosis, secondary changes in the RV and pulmonary arteries can occur. The infundibular region of the RV becomes hypertrophied with resultant dynamic subvalvular obstruction. This hypertrophy can persist in the immediate post-valvuloplasty period, resulting in limited pulmonary outflow. Over time, once the fixed pulmonary obstruction is removed, this hypertrophy resolves.
49. You are performing an echocardiogram on an asymptomatic 4-month-old girl referred for a cardiac murmur. You note discrete stenosis of the proximal LPA, measuring 2 mm. The distal LPA is 6 mm. The RPA is 8 mm. The pulmonary valve and MPA are normal. There is no ASD or VSD. Peak Doppler velocity across the LPA stenosis is 2.0 m/s. Right ventricular systolic pressure (RVSP) is estimated to be 25 mm Hg. There is mild RV hypertrophy. Which of the following statements is true?
A. The degree of LPA stenosis is mild
C. Invasive pressure measurements would be likely to show an MPA-to-LPA gradient that is much higher than that estimated by Doppler flow velocity.
D. If angioplasty is performed, a 6- to 8-mm balloon should be used
E. The risk of restenosis after angioplasty is approximately 3% to 5%
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. A newborn infant is cyanotic, and echocardiography reveals pulmonary atresia with intact ventricular septum. The right ventricle is bipartite and quite small. The baby is receiving PGE1. Which of the following is the next step in the management of this patient?
A. Balloon atrial septostomy
B. Surgical outflow tract reconstruction
C. Cardiac catheterization and angiography
D. Cardiac CT scan
E. Cardiac MRI
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. Which of the following anatomical substrates most likely predicts a successful decompression of the RV using radiofrequency ablation and balloon pulmonary valvotomy in patients with pulmonary atresia with intact ventricular septum?
A. Unipartite RV
B. Muscular pulmonary atresia
C. RV-dependent coronary circulation
D. Severe tricuspid stenosis
E. Tricuspid valve Z-score = -2
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. The angiogram demonstrated in Figure 2.4 is performed in a 9-month-old boy with pulmonary atresia and intact ventricular septum.
Which of the following operations is best for this patient?
A. Bidirectional Glenn alone
B. RV-PA conduit with a bidirectional Glenn
C. RV-PA conduit alone
D. Pulmonary valvotomy alone
E. Pulmonary valvotomy with a bidirectional Glenn
A. Complete heart block
B. Left bundle branch block
C. ST-segment elevation in I, aVL
D. ST-segment elevation in II, III, aVF
E. Increased voltages in V1, V2, V3
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. You are seeing a 4-day-old infant with cyanosis. Echocardiography reveals pulmonary atresia with intact ventricular septum. There is significant subpulmonary (infundibular) obstruction. The RV appears tripartite but severely hypoplastic. By echocardiography, there is no evidence of RV-dependent coronary circulation. You are planning an eventual biventricular repair beginning with a surgical pulmonary valvuloplasty and RVOT patch enlargement. What is the best next step in surgical planning?
A. Go to surgery without further testing
B. Cardiac catheterization with hemodynamic study only
C. Catheterization with hemodynamic assessment and RV angiography
E. Biopsy of RV myocardium to evaluate for spongy myocardium and/or endocardial sclerosis
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. A newborn is found to have cyanosis shortly after birth. A holosystolic murmur is heard and PGE1 is started. An echocardiogram is performed (Figure 2.5):
Color flow Doppler fails to show antegrade flow in the MPA. The ventricular septum is intact. Which of the following is true regarding neonates with this form of congenital heart disease?
A. Coronary artery perfusion is wholly RV dependent in about 45% of cases
B. Pulmonary blood flow most often is supplied by aortopulmonary collaterals
C. This form of congenital heart disease is more common in males
D. By definition, the right ventricle is always bipartite
E. A main pulmonary trunk almost always is present
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. A 3-year-old boy has pulmonary atresia with VSD. He has a history of hypoplastic central pulmonary arteries and multiple major aortopulmonary collateral arteries (MAPCA), with multiple surgeries including a central shunt as well as right and left unifocalization surgeries. He is admitted for complete repair. Following reconstruction of the central confluence, placement of an RV-PA conduit, takedown of two MAPCAs, and VSD closure, he does not tolerate coming off bypass. His blood pressure is 84/60 mm Hg on multiple pressors. His saturation is 87% on 100% oxygen. His RV pressure is 69/15 mm Hg. TEE demonstrates patency of the conduit. What is the best course of action?
A. Placement of ECMO until hemodynamics improve
B. Reinstitution of bypass, takedown of RV-PA conduit, and placement of a central shunt
C. Replacement of the RV-PA conduit with a larger conduit
D. Treatment with nitric oxide to improve PVR
E. Reopening the VSD
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).
57. An 11-year-old boy with history of pulmonary atresia with VSD is status post a BT shunt early in life and is also status post multiple unifocalization procedures. He is in the operating room for a complete repair. The surgeon has completed the operation. You are performing an echocardiogram. You note that the VSD is now closed and the RV-PA conduit has laminar flow by color Doppler. The estimated RV systolic pressure is 80 mm Hg. Biventricular function appears reasonable. You see that the radial arterial pressure tracing is 100/50 mm Hg. You advise the surgeon to:
A. Do nothing further
B. Replace the conduit with a smaller one
C. Replace the conduit with a larger one
D. Reopen the VSD
E. Place a BT shunt in addition to what has been done already
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. A 4-month-old infant with pulmonary atresia with VSD undergoes complete repair, including unifocalization, RV-PA conduit, and closure of the VSD. Before sternal closure in the operating room, she becomes hypotensive. Systemic arterial pressure is 65/45 mm Hg. She is edematous with hepatomegaly. TEE reveals RV hypertrophy and moderately decreased biventricular systolic function. She has moderate tricuspid regurgitation with a velocity of 3.5 m/s. Which of the following interventions is most urgent at this time?
B. Leave the chest open and return to the ICU
C. Reopen the VSD
D. Placement of a bidirectional Glenn
59. A neonate with pulmonary atresia (PA) with VSD undergoes heart catheterization. The angiogram in Figure 2.6 is obtained.
What is the primary source of pulmonary blood flow in this patient?
A. Ascending aorta
B. Descending aorta
C. Patent ductus arteriosus
D. BT shunt
E. Right subclavian artery
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.
A. Along the posteroinferior rim of the VSD on the left ventricular side
B. Along the posterosuperior rim of the VSD on the right ventricular side
C. Along the anterolateral rim of the VSD on the left ventricular side
D. Along the anteromedial rim of the VSD on the right ventricular side
E. Not enough information provided
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. A 12-year-old patient with unrepaired TOF presents to clinic for preoperative evaluation before a planned complete surgical repair. Physical examination reveals severe cyanosis with marked clubbing of the fingers. Cardiac examination reveals a normal S1, single S2, with a grade 2/6 systolic ejection murmur at the left upper sternal border. There is also a soft continuous murmur over interscapular area. Echocardiography demonstrates severe right ventricular hypertrophy, anterocephalad malalignment of the conal septum, and a large perimembranous VSD with an overriding aorta. Owing to difficult visualization of the pulmonary artery anatomy, a cardiac catheterization is planned for the next morning at 8:30 am. Which of the following should be done to decrease the chance of a hypercyanotic spell in the morning?
A. Make the patient NPO after midnight and start an IV at 7:00 am
B. Use a general anesthesia-inducing agent that decreases systemic vascular resistance more than PVR
C. Make the patient NPO after midnight, perform phlebotomy to decrease Hgb to <14 before starting the IV
D. Start an esmolol drip as soon as the procedure starts
E. Make the patient NPO after midnight, start IV fluid when NPO starts, and use a topical anesthetic such as EMLA before attempting vascular access
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. A 17-year-old female with a history of tetralogy of Fallot (TOF) with a left aortic arch presents with progressive dyspnea on exertion. She describes a history of multiple operations including an RV-PA conduit revision 2 years ago. As part of her evaluation, cardiac catheterization is performed, from which the data in Table 2.2 are obtained.
TABLE 2.2 Cardiac Catheterization Data
On the basis of the information, which of the following is most likely to be true?
A. She would benefit from sildenafil
B. She would benefit from closure of her left-to-right shunt
C. She should have a conduit revision
D. Her symptoms are primarily related to diastolic dysfunction
E. She has a history of a Waterston shunt
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. A 6-day-old male infant presents with cyanosis and tachypnea. An echocardiogram confirms the diagnosis of tetralogy of Fallot (TOF) with absent pulmonary valve. He is in moderate respiratory distress. His heart rate is 190 bpm, respiratory rate is 55/min, and his ABG shows PaO2 = 67, PaCO2 = 68, pH = 7.25, Bicarb = 17, and an oxygen saturation of 84%. What should be done next in an attempt to alleviate his respiratory distress?
A. Inhaled albuterol
B. Intubation and mechanical ventilation
C. IV solumedrol
D. Emergent surgical repair of his congenital heart disease
E. Placement in prone position
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. A 3-day-old male infant presents to the emergency department with cyanosis. He was diagnosed prenatally with tetralogy of Fallot. He was born at home at 35 and 4/7 weeks of gestation. Over the first 48 hours of life, his color was good and he was nursing well. However, over the past 2 to 4 hours, he appeared progressively blue. At the time of presentation, his oxygen saturations are 60% to 65%, and he appears dusky. He is becoming more dusky. On examination, he has no appreciable murmur. A UVC has been placed. What is the best next step in management?
A. Echocardiogram to ascertain whether his prenatal echo had the correct diagnosis
B. Hyperoxia test to try to ascertain if he has a pulmonary component of his cyanosis
C. Emergent surgical repair
D. IV prostaglandin
E. IV morphine to encourage left-to-right shunting across his VSD
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. A 6-day-old male infant presents with a cardiac murmur and cyanosis. His saturation is 69% and his cuff blood pressure is 65/37 mm Hg. An echocardiogram reveals the following: TOF; severe infundibular obstruction (narrowest diameter 2 to 3 mm), a bicuspid pulmonary valve measuring ˜5 mm at the annulus; almost entirely right-to-left shunting at the VSD with a peak Doppler VSD velocity of 2.5 m/s; accessory tricuspid valve tissue prolapsing into the VSD during systole; and a tricuspid regurgitation velocity of 4.5 m/s. He has an enlarged coronary sinus draining a left SVC. He has a large conal branch from his right coronary artery. Among the findings below, which feature is the most unusual in patients with TOF?
A. Large conal branch
B. Left SVC
C. Restrictive VSD
D. Pulmonary valve stenosis
E. Predominant right-to-left shunting through the VSD
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. A 3-week-old infant presents with tachypnea and poor feeding. Her prenatal screening ultrasound was suggestive of a severe conotruncal defect, but she was lost to follow-up and was a home delivery. Today, vital signs are as follows: P = 140 beats per minute, BP = 80/35 mm Hg, RR = 60 breaths per minute, O2 saturation = 93% (room air). Cardiac examination reveals an active precordium, normal S1, single S2 with a grade 2/6 systolic murmur at left-mid sternal border. When the baby is quiet, a soft continuous murmur becomes apparent in the back. Which of the following statements is correct regarding this scenario?
A. The continuous murmur strongly suggests a diagnosis of truncus arteriosus
B. The continuous murmur is the result of truncal valve stenosis and regurgitation
C. Physical examination findings suggest a diagnosis of pulmonary atresia with VSD more than truncus arteriosus
D. Physical examination findings suggest a diagnosis of pulmonary atresia with intact ventricular septum more than truncus arteriosus
E. The presence of an apical diastolic murmur in this patient suggests anatomical mitral valve stenosis
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.
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