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ABIM ACHD practice questions

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Question 1Basic Science and Epidemiology of Congenital Heart Disease

Cardiac neural crest cells migrating into the pharyngeal arches are most important for forming which structure?

  1. Primitive ventricle
  2. Atrioventricular cushions
  3. Aorticopulmonary septum Correct answer.
  4. Sinus venosus

Explanation

Cardiac neural crest cells form the aorticopulmonary septum and conotruncal ridges, separating the truncus arteriosus into the aorta and pulmonary trunk. Failure of this process produces conotruncal defects such as truncus arteriosus and tetralogy of Fallot. The other structures arise mainly from endocardial or lateral plate mesoderm.

Question 2Basic Science and Epidemiology of Congenital Heart Disease

A neonate with truncus arteriosus and hypocalcemia is most likely to have which genetic abnormality?

  1. Trisomy 13
  2. FBN1 mutation
  3. 22q11.2 deletion Correct answer.
  4. JAG1 mutation

Explanation

22q11.2 deletion syndrome (DiGeorge syndrome) causes conotruncal cardiac defects and hypocalcemia due to parathyroid hypoplasia. Truncus arteriosus is a classic conotruncal lesion in this disorder. FBN1 and JAG1 mutations cause Marfan and Alagille syndromes, respectively.

Question 3Basic Science and Epidemiology of Congenital Heart Disease

Approximately what proportion of live-born infants has congenital heart disease?

  1. 5%
  2. 0.1%
  3. 1% Correct answer.
  4. 10%

Explanation

Congenital heart disease occurs in approximately 0.8% to 1.2% of live births, making it the most common major birth defect. Higher figures often include minor lesions detected only by sensitive screening. A prevalence of 5% to 10% would vastly exceed observed birth-cohort data.

Question 4Basic Science and Epidemiology of Congenital Heart Disease

Functional closure of the ductus arteriosus shortly after birth is primarily driven by which change?

  1. Rise in arterial oxygen tension Correct answer.
  2. Rise in pulmonary vascular resistance
  3. Fall in systemic vascular resistance
  4. Closure of the foramen ovale

Explanation

After birth, a rise in arterial oxygen tension constricts the ductal smooth muscle, and falling prostaglandin E2 levels contribute to closure. The fall in pulmonary vascular resistance and loss of placental circulation accompany this process but are not the direct constrictor signal. Anatomic closure follows functional closure over days to weeks.

Question 5Basic Science and Epidemiology of Congenital Heart Disease

Which cardiac defect is most characteristic of Down syndrome?

  1. Transposition of the great arteries
  2. Atrioventricular septal defect Correct answer.
  3. Ebstein anomaly
  4. Anomalous left coronary artery from the pulmonary artery

Explanation

Atrioventricular septal defect is strongly associated with trisomy 21 and occurs in a large minority of affected children. Transposition, Ebstein anomaly, and ALCAPA are not characteristic of Down syndrome. Echocardiography is recommended for all infants with trisomy 21.

Question 6Basic Science and Epidemiology of Congenital Heart Disease

Which cardiovascular lesion is most strongly associated with Turner syndrome?

  1. Tricuspid atresia
  2. Coarctation of the aorta Correct answer.
  3. Tetralogy of Fallot
  4. Total anomalous pulmonary venous return

Explanation

Turner syndrome (45,X) is associated with left-sided obstructive lesions, especially coarctation of the aorta and bicuspid aortic valve. These patients also require lifelong surveillance for aortic dilation and dissection. The other lesions are not typical of Turner syndrome.

Question 7Basic Science and Epidemiology of Congenital Heart Disease

Maternal rubella infection during early pregnancy is most associated with which cardiac finding?

  1. Atrioventricular septal defect
  2. Aortic dissection
  3. Myocardial infarction
  4. Pulmonary artery stenosis Correct answer.

Explanation

Congenital rubella syndrome classically causes pulmonary artery branch stenosis and patent ductus arteriosus, along with cataracts and deafness. The virus affects early fetal development during maternal viremia. Aortic dissection, AV septal defect, and myocardial infarction are not part of the classic syndrome.

Question 8Basic Science and Epidemiology of Congenital Heart Disease

In the normal fetus, the foramen ovale primarily allows blood to pass in which direction?

  1. Right ventricle to aorta
  2. Right atrium to left atrium Correct answer.
  3. Left atrium to right atrium
  4. Pulmonary artery to aorta

Explanation

The foramen ovale is a right-to-left shunt that directs oxygenated umbilical venous blood from the right atrium to the left atrium in fetal life. This streaming supplies the developing brain and coronary circulation. After birth, rising left atrial pressure closes the flap functionally.

Question 9Basic Science and Epidemiology of Congenital Heart Disease

A couple has one child with a ventricular septal defect and no family history. What is the approximate recurrence risk for a future sibling?

  1. 25%
  2. 0.1%
  3. 50%
  4. 3% Correct answer.

Explanation

Most isolated congenital heart defects show multifactorial inheritance, with sibling recurrence risk of about 2% to 4%. This is higher than the population risk but far below Mendelian expectations. Recurrence can be higher when multiple relatives are affected or a syndrome is present.

Question 10Basic Science and Epidemiology of Congenital Heart Disease

A secundum atrial septal defect results from deficiency of which structure?

  1. Bulbus cordis
  2. Septum primum
  3. Septum secundum Correct answer.
  4. Endocardial cushion

Explanation

A secundum atrial septal defect is caused by deficiency of the septum secundum or excessive resorption of the septum primum, leaving an opening at the fossa ovalis. Primum defects instead involve the endocardial cushions and are part of atrioventricular septal defects. The bulbus cordis contributes to the right ventricle and outflow tract.

Question 11Basic Science and Epidemiology of Congenital Heart Disease

Maternal use of lithium during pregnancy is most associated with which cardiac anomaly?

  1. Transposition of the great arteries
  2. Ebstein anomaly Correct answer.
  3. Atrioventricular septal defect
  4. Coarctation of the aorta

Explanation

Lithium exposure in early pregnancy has been linked to Ebstein anomaly, a malformation of the tricuspid valve with downward displacement of its septal leaflet. The absolute risk is low, so lithium is not absolutely contraindicated when clinically necessary. The other listed lesions have different teratogenic or genetic associations.

Question 12Basic Science and Epidemiology of Congenital Heart Disease

Pregestational maternal diabetes increases the risk of congenital heart disease by approximately what factor?

  1. No increase
  2. Twofold
  3. Fiftyfold
  4. Fivefold Correct answer.

Explanation

Pregestational diabetes roughly triples to quintuples the risk of congenital heart disease, with conotruncal and septal defects among the most common. Hyperglycemia during early cardiogenesis is thought to mediate teratogenesis. A fiftyfold increase would be far beyond observed epidemiologic data.

Question 13Basic Science and Epidemiology of Congenital Heart Disease

In the normal near-term fetus, blood in the umbilical vein has an oxygen saturation closest to which value?

  1. 20%
  2. 80% Correct answer.
  3. 60%
  4. 40%

Explanation

Umbilical venous blood is the most oxygenated fetal blood, with saturation around 80% to 85% because of placental gas exchange. The umbilical arteries return desaturated blood at about 55% to 60%. Fetal tissues tolerate lower oxygen tension than adult tissues.

Question 14Basic Science and Epidemiology of Congenital Heart Disease

What proportion of infants born with congenital heart disease now survive to adulthood?

  1. 30%
  2. 90% Correct answer.
  3. 10%
  4. 60%

Explanation

With advances in diagnosis, surgery, and catheter intervention, more than 90% of children born with congenital heart disease now survive to adulthood. This has produced a rapidly growing adult congenital heart disease population. Survival is lower for the most complex lesions but has also improved substantially.

Question 15Basic Science and Epidemiology of Congenital Heart Disease

A family has atrial septal defects and progressive atrioventricular block across generations. Which gene mutation is most likely?

  1. NKX2-5 Correct answer.
  2. FBN1
  3. PTPN11
  4. CHD7

Explanation

NKX2-5 mutations cause familial atrial septal defects with conduction abnormalities, especially progressive atrioventricular block. FBN1 causes Marfan syndrome, PTPN11 causes Noonan syndrome, and CHD7 causes CHARGE syndrome. These other genes are not classically associated with familial ASD and heart block.

Question 16Basic Science and Epidemiology of Congenital Heart Disease

A child with butterfly vertebrae, cholestasis, and peripheral pulmonary stenosis most likely has a mutation in which gene?

  1. TBX1
  2. MYH7
  3. GATA4
  4. JAG1 Correct answer.

Explanation

Alagille syndrome is caused by JAG1 mutations (or less often NOTCH2) and features bile duct paucity, butterfly vertebrae, posterior embryotoxon, and peripheral pulmonary artery stenosis. TBX1 is implicated in 22q11.2 deletion, while GATA4 and MYH7 cause other cardiac phenotypes. The constellation is not explained by those genes.

Question 17Basic Science and Epidemiology of Congenital Heart Disease

Bicuspid aortic valve occurs in approximately what proportion of the general population?

  1. 0.01%
  2. 10%
  3. 0.1%
  4. 1% Correct answer.

Explanation

Bicuspid aortic valve is the most common congenital cardiac malformation, affecting about 1% to 2% of the population. It can lead to aortic stenosis, regurgitation, and aortopathy. A prevalence of 10% would be far too high, while 0.01% and 0.1% are too low.

Question 18Basic Science and Epidemiology of Congenital Heart Disease

After birth, pulmonary vascular resistance falls primarily because of which change?

  1. Decreased systemic vascular resistance
  2. Oxygen-induced pulmonary vasodilation Correct answer.
  3. Increased left atrial pressure
  4. Closure of the ductus arteriosus

Explanation

Lung expansion, increased oxygen tension, and increased pulmonary blood flow cause active pulmonary vasodilation immediately after birth. Structural remodeling of the pulmonary arteries then lowers resistance further over weeks to months. Ductal closure and left atrial pressure changes are consequences of the transition, not the primary cause of the fall.

Question 19Basic Science and Epidemiology of Congenital Heart Disease

The ductus venosus shunts oxygenated umbilical venous blood directly into which structure?

  1. Inferior vena cava Correct answer.
  2. Portal vein
  3. Descending thoracic aorta
  4. Right ventricle

Explanation

The ductus venosus connects the umbilical vein to the inferior vena cava, bypassing the hepatic sinusoids. This allows well-oxygenated blood to reach the heart and then stream preferentially through the foramen ovale. It closes functionally after birth as umbilical flow ceases.

Question 20Basic Science and Epidemiology of Congenital Heart Disease

A neonate with ductal-dependent pulmonary blood flow is started on prostaglandin E1. The drug works by doing which of the following?

  1. Reducing pulmonary vascular resistance
  2. Closing the ductus arteriosus
  3. Increasing myocardial contractility
  4. Dilating the ductus arteriosus Correct answer.

Explanation

Prostaglandin E1 relaxes the smooth muscle of the ductus arteriosus, keeping it patent in ductal-dependent lesions such as pulmonary atresia. It does not directly increase contractility or lower pulmonary vascular resistance. Side effects include apnea and hypotension.

Question 21Basic Science and Epidemiology of Congenital Heart Disease

Familial bicuspid aortic valve with early aortic valve calcification has been linked to mutations in which signaling pathway?

  1. NOTCH1 Correct answer.
  2. TGFBR2
  3. FBN1
  4. PTPN11

Explanation

Loss-of-function NOTCH1 mutations have been identified in families with bicuspid aortic valve and premature valve calcification. NOTCH1 signaling is important for endothelial-to-mesenchymal transition and valve development. TGFBR2, PTPN11, and FBN1 are associated with other connective tissue or syndromic disorders.

Question 22Basic Science and Epidemiology of Congenital Heart Disease

Exposure to isotretinoin during early gestation is most strongly associated with which pattern of cardiac defects?

  1. Atrioventricular septal defect
  2. Ebstein anomaly
  3. Pulmonary vein stenosis
  4. Conotruncal anomalies Correct answer.

Explanation

Retinoic acid embryopathy causes conotruncal defects such as tetralogy of Fallot and transposition, along with aortic arch anomalies. The critical exposure window overlaps early neural crest and pharyngeal arch development. AV septal defect, pulmonary vein stenosis, and Ebstein anomaly have other classic associations.

Question 23Basic Science and Epidemiology of Congenital Heart Disease

Coronary artery ostia are normally formed by ingrowth of vessels from which embryonic structure into the aortic sinuses?

  1. Endocardial cushions
  2. Cardiac neural crest
  3. Epicardial ring Correct answer.
  4. Second aortic arch

Explanation

Coronary vessels arise from an epicardial peritruncal vascular ring that grows into the aortic root and connects to the aortic sinuses. Defects in this process can cause anomalous coronary origins. Endocardial cushions, neural crest, and the second aortic arch do not form the coronary ostia.

Question 24Basic Science and Epidemiology of Congenital Heart Disease

The pulmonary veins develop primarily from which embryonic structure?

  1. Splanchnic venous plexus
  2. Sixth pharyngeal aortic arch
  3. Primitive left atrium Correct answer.
  4. Sinus venosus

Explanation

The common pulmonary vein develops as an outpouching of the primitive left atrium and connects to the pulmonary venous plexus. Failed connection can produce total anomalous pulmonary venous return. The sinus venosus contributes to systemic venous return, and the sixth arch contributes to the ductus arteriosus.

Question 25Basic Science and Epidemiology of Congenital Heart Disease

Chromosomal microarray is preferred over standard karyotype in many children with congenital heart disease because it can detect which finding?

  1. Submicroscopic deletions Correct answer.
  2. Mitochondrial DNA rearrangements
  3. Balanced reciprocal translocations
  4. Single-gene point mutations

Explanation

Chromosomal microarray detects copy-number variants, including submicroscopic deletions and duplications such as the 22q11.2 deletion, that karyotype may miss. It does not reliably detect balanced translocations, point mutations, or mitochondrial DNA rearrangements. Those require other tests such as sequencing or specific cytogenetic methods.

Question 26Basic Science and Epidemiology of Congenital Heart Disease

A newborn has a ventricular septal defect, an overriding aorta, and severe pulmonary stenosis, and genetic testing shows a 22q11.2 microdeletion. Which category of cardiac defect does this lesion belong to?

  1. Atrioventricular septal defect
  2. Conotruncal defect Correct answer.
  3. Left-sided obstructive lesion
  4. Anomalous pulmonary venous connection

Explanation

The 22q11.2 deletion removes TBX1 and disrupts neural-crest-dependent outflow tract septation, producing conotruncal anomalies such as tetralogy of Fallot, truncus arteriosus, and type B interrupted aortic arch. The lesion described is tetralogy of Fallot, which sits in this conotruncal group.

Question 27Basic Science and Epidemiology of Congenital Heart Disease

Which congenital cardiac lesion is most characteristic of trisomy 21?

  1. d-Transposition of the great arteries
  2. Ebstein anomaly
  3. Valvar pulmonary stenosis
  4. Atrioventricular septal defect Correct answer.

Explanation

Trisomy 21 is strongly associated with atrioventricular septal defects, including complete forms with a common valve and a primum-type atrial communication. Roughly 40% to 50% of children with Down syndrome have congenital heart disease, and an atrioventricular septal defect is the single most characteristic lesion.

Question 28Basic Science and Epidemiology of Congenital Heart Disease

Approximately what proportion of liveborn infants has congenital heart disease?

  1. 5%
  2. 1% Correct answer.
  3. 0.3%
  4. 0.1%

Explanation

Congenital heart disease is present in roughly 8 to 9 per 1000 live births, which is about 1%. The figure rises to about 13 per 1000 when bicuspid aortic valve and small muscular septal defects detected only by echocardiography are included.

Question 29Basic Science and Epidemiology of Congenital Heart Disease

Which congenital cardiac lesion is the most common overall?

  1. Tetralogy of Fallot
  2. Secundum atrial septal defect
  3. Coarctation of the aorta
  4. Ventricular septal defect Correct answer.

Explanation

Ventricular septal defect accounts for roughly 30% to 40% of all congenital cardiac lesions and is the single most common defect, although many small muscular defects close spontaneously. Secundum atrial septal defect, patent ductus arteriosus, and pulmonary stenosis follow in frequency.

Question 30Basic Science and Epidemiology of Congenital Heart Disease

A 16-year-old boy is unusually tall with arachnodactyly, upward lens dislocation, and a dilated aortic root. Which genetic abnormality best explains this presentation?

  1. FBN1 encoding fibrillin-1 Correct answer.
  2. ACTA2 encoding smooth muscle actin
  3. COL3A1 encoding type III collagen
  4. TGFBR2 encoding a TGF-beta receptor

Explanation

Marfan syndrome results from heterozygous FBN1 mutations that reduce fibrillin-1 in the extracellular matrix, producing cystic medial degeneration of the aortic root. Progressive aortic root dilation with risk of dissection is the major cardiovascular complication.

Question 31Basic Science and Epidemiology of Congenital Heart Disease

A child has absent thumbs, a hypoplastic radius, and a large secundum atrial septal defect, and the father has a similar radial limb anomaly. Which gene is most likely mutated?

  1. NKX2-5
  2. JAG1
  3. GATA4
  4. TBX5 Correct answer.

Explanation

Holt-Oram syndrome is caused by TBX5 haploinsufficiency and combines radial ray limb defects with atrial or ventricular septal defects and conduction disease. The autosomal dominant inheritance with limb involvement distinguishes it from isolated familial septal defects.

Question 32Basic Science and Epidemiology of Congenital Heart Disease

An infant has short stature, a webbed neck, hypertelorism, and a dysplastic pulmonary valve with stenosis, and karyotype is normal. Which diagnosis is most likely?

  1. Williams syndrome
  2. Noonan syndrome Correct answer.
  3. Marfan syndrome
  4. CHARGE syndrome

Explanation

Noonan syndrome is a RASopathy, most often caused by PTPN11 mutations, and characteristically produces dysplastic pulmonary valve stenosis and hypertrophic cardiomyopathy in a child with short stature, webbed neck, and hypertelorism. The normal karyotype distinguishes it from Turner syndrome, which shares some facial features.

Question 33Basic Science and Epidemiology of Congenital Heart Disease

The ductus arteriosus is derived from which pharyngeal arch artery?

  1. First
  2. Fourth
  3. Sixth Correct answer.
  4. Second

Explanation

The distal portion of the sixth pharyngeal arch artery persists as the ductus arteriosus, while its proximal portion contributes to the pulmonary artery. The fourth arch artery forms the definitive aortic arch on the left and the proximal right subclavian on the right.

Question 34Basic Science and Epidemiology of Congenital Heart Disease

Populations living at high altitude show a substantially higher birth prevalence of which congenital cardiac lesion than sea-level populations?

  1. Aortic stenosis
  2. Patent ductus arteriosus Correct answer.
  3. Secundum atrial septal defect
  4. Tetralogy of Fallot

Explanation

Chronic fetal hypoxemia at altitude impairs oxygen-mediated constriction of the ductus arteriosus, and high-altitude populations have a well-documented excess of patent ductus arteriosus. The same populations also show exaggerated pulmonary vascular reactivity.

Question 35Basic Science and Epidemiology of Congenital Heart Disease

A woman with poorly controlled phenylketonuria (phenylalanine above 1200 micromol/L) becomes pregnant. Which outcome is most strongly increased in her offspring?

  1. Isolated cleft palate only
  2. Congenital heart disease and microcephaly Correct answer.
  3. Neonatal thyrotoxicosis
  4. Congenital complete heart block

Explanation

Phenylalanine is teratogenic, and the risk of maternal phenylketonuria embryopathy rises with maternal concentrations. The characteristic features are cardiac defects, microcephaly, growth restriction, and intellectual disability rather than a single isolated malformation.

Question 36Basic Science and Epidemiology of Congenital Heart Disease

A pregnant woman with systemic lupus erythematosus is positive for anti-Ro/SSA antibodies. Serial fetal echocardiography is performed mainly to detect which complication?

  1. Fetal pericardial effusion with tamponade
  2. Progressive aortic root dilatation
  3. Complete atrioventricular block Correct answer.
  4. Ductal constriction with right heart failure

Explanation

Maternal anti-Ro/SSA and anti-La/SSB IgG cross the placenta from about 16 weeks and can cause immune-mediated fibrosis of the fetal atrioventricular node. The resulting complete heart block is irreversible and carries substantial morbidity, so serial fetal echocardiography is used for surveillance.

Question 37Basic Science and Epidemiology of Congenital Heart Disease

Newborn pulse oximetry screening for critical congenital heart disease is best performed in which way?

  1. A single measurement from the right hand at 24 hours of age
  2. A single right-hand reading taken at 6 hours of age
  3. A single foot reading taken before hospital discharge
  4. Paired right-hand and foot readings after 24 hours Correct answer.

Explanation

Screening pairs a pre-ductal right-hand reading with a post-ductal foot reading after 24 hours of age. A saturation below 90% at either site, or a difference of more than 3 percentage points between sites, is a positive screen that prompts echocardiography.

Question 38Basic Science and Epidemiology of Congenital Heart Disease

A 5-month-old with a large unrestrictive ventricular septal defect undergoes catheterization. Saturations are systemic artery 95%, mixed venous 70%, pulmonary vein 98%, and pulmonary artery 80%. What is the pulmonary-to-systemic flow ratio (Qp/Qs)?

  1. 1.0
  2. 2.5
  3. 0.7
  4. 1.4 Correct answer.

Explanation

Qp/Qs is calculated as (systemic arterial saturation minus mixed venous saturation) divided by (pulmonary venous saturation minus pulmonary arterial saturation), giving (95 minus 70) divided by (98 minus 80), or 25/18, which is approximately 1.4. A ratio above 1 confirms a net left-to-right shunt.

Question 39Basic Science and Epidemiology of Congenital Heart Disease

Growth of ventricular myocardium in the fetus and early neonate occurs predominantly by which mechanism?

  1. Fibroblast-to-myocyte transdifferentiation
  2. Recruitment of circulating progenitor cells
  3. Hypertrophy of existing myocytes
  4. Hyperplasia of cardiomyocytes Correct answer.

Explanation

Fetal and early neonatal cardiomyocytes proliferate, so cardiac growth at that stage results mainly from hyperplasia. Shortly after birth myocytes largely withdraw from the cell cycle, become binucleated or polyploid, and subsequent growth occurs by hypertrophy.

Question 40Basic Science and Epidemiology of Congenital Heart Disease

A 4-year-old has polysplenia, interruption of the inferior vena cava with azygos continuation, and complete atrioventricular block. Which diagnosis is most consistent with this combination?

  1. Right atrial isomerism
  2. Heterotaxia with normal situs
  3. Left atrial isomerism Correct answer.
  4. Isolated dextrocardia

Explanation

Left atrial isomerism, or polysplenia syndrome, features bilateral morphologic left atria, interruption of the inferior vena cava with azygos continuation, and displacement of the conduction system that predisposes to atrioventricular block. Cyanotic complex lesions are less typical than in right isomerism.

Question 41Anatomy, Pathophysiology, and Natural History of Congenital Lesions

A newborn has a small muscular ventricular septal defect. Which statement best describes the expected natural history?

  1. They typically enlarge as the child grows, increasing the left-to-right shunt
  2. Most small muscular defects close spontaneously during the first years of life Correct answer.
  3. They invariably progress to Eisenmenger syndrome in adulthood
  4. Most require surgical closure before 6 months of age because of heart failure

Explanation

Small muscular and perimembranous ventricular septal defects have a high rate of spontaneous closure, especially during early childhood. Large defects are the ones that cause heart failure and may need early intervention. Eisenmenger physiology is uncommon with a small restrictive defect.

Question 42Anatomy, Pathophysiology, and Natural History of Congenital Lesions

A secundum atrial septal defect is located in which portion of the atrial septum?

  1. Adjacent to the aortic root above the membranous septum
  2. At the superior vena cava–right atrial junction
  3. Inferior to the fossa ovalis, near the coronary sinus
  4. Within the central portion of the fossa ovalis Correct answer.

Explanation

A secundum defect lies within the fossa ovalis in the central atrial septum. Primum defects are inferior and adjacent to the atrioventricular valves, while sinus venosus defects are near the superior or inferior vena cava.

Question 43Anatomy, Pathophysiology, and Natural History of Congenital Lesions

In a term infant with a large patent ductus arteriosus, which hemodynamic pattern is expected?

  1. Right-to-left shunt causing differential cyanosis
  2. Left-to-right shunt confined to systole only
  3. No shunt because pulmonary vascular resistance exceeds systemic resistance at birth
  4. Continuous left-to-right shunt with pulmonary overcirculation Correct answer.

Explanation

After birth, pulmonary vascular resistance falls and aortic pressure exceeds pulmonary artery pressure throughout the cardiac cycle. This produces continuous left-to-right flow through the ductus, causing pulmonary overcirculation. Right-to-left ductal flow occurs when pulmonary vascular resistance remains very high.

Question 44Anatomy, Pathophysiology, and Natural History of Congenital Lesions

Which combination of findings defines tetralogy of Fallot?

  1. Transposition, VSD, and pulmonary stenosis
  2. VSD, overriding aorta, pulmonary obstruction, and RV hypertrophy Correct answer.
  3. Aortic stenosis, hypoplastic left ventricle, and mitral atresia
  4. VSD, ASD, PDA, and right aortic arch

Explanation

Tetralogy of Fallot consists of a ventricular septal defect, an overriding aorta, right ventricular outflow tract obstruction, and right ventricular hypertrophy. The hypertrophy is a consequence of the outflow obstruction. Associated lesions such as a right aortic arch may occur but are not part of the definition.

Question 45Anatomy, Pathophysiology, and Natural History of Congenital Lesions

A 6-year-old has hypertension in the arms with weak femoral pulses. Which lesion best explains these findings?

  1. Secundum atrial septal defect
  2. Patent ductus arteriosus
  3. Coarctation of the aorta Correct answer.
  4. Mild pulmonary valve stenosis

Explanation

Coarctation of the aorta obstructs flow distal to the arch, producing upper extremity hypertension and diminished lower extremity pulses. A pressure gradient and radiofemoral delay are typical. The other lesions do not produce this upper-lower blood pressure discrepancy.

Question 46Anatomy, Pathophysiology, and Natural History of Congenital Lesions

Which auscultatory finding is most characteristic of moderate valvar pulmonary stenosis?

  1. Systolic ejection murmur at the left upper sternal border with a click Correct answer.
  2. Decrescendo diastolic murmur at the right upper sternal border radiating to the apex
  3. Continuous machinery murmur below the clavicle
  4. Holosystolic murmur at the apex radiating to the axilla with an S3

Explanation

Valvar pulmonary stenosis produces a harsh systolic ejection murmur at the left upper sternal border, often with an ejection click and radiation to the back. The click reflects abrupt valve opening. Continuous murmurs and decrescendo diastolic murmurs indicate different lesions.

Question 47Anatomy, Pathophysiology, and Natural History of Congenital Lesions

Which statement best characterizes the natural history of a bicuspid aortic valve?

  1. It remains functionally normal throughout life in nearly all patients
  2. It usually causes severe neonatal heart failure requiring urgent surgery
  3. It predisposes to aortic stenosis, regurgitation, and aortopathy Correct answer.
  4. It is typically associated with pulmonary valve dysplasia

Explanation

Bicuspid aortic valves often function normally in childhood but commonly develop progressive calcific stenosis or regurgitation in adulthood. The associated aortopathy can lead to aortic dilation and dissection. Severe neonatal presentation is uncommon.

Question 48Anatomy, Pathophysiology, and Natural History of Congenital Lesions

A newborn with critical aortic valve stenosis typically presents with which findings?

  1. A continuous murmur and pulmonary plethora
  2. Cyanosis from a right-to-left atrial shunt and absent femoral pulses
  3. Wide pulse pressure and bounding pulses
  4. Poor perfusion, metabolic acidosis, and a systolic ejection murmur Correct answer.

Explanation

Critical aortic stenosis obstructs left ventricular output and can cause low cardiac output, poor perfusion, and metabolic acidosis in the newborn. Systemic flow may depend on ductal patency. A systolic ejection murmur is often present but may be soft when output is low.

Question 49Anatomy, Pathophysiology, and Natural History of Congenital Lesions

Which physiologic feature is expected after a Fontan operation?

  1. Passive pulmonary blood flow driven by systemic venous pressure Correct answer.
  2. A subpulmonary ventricle generating pulsatile pulmonary flow
  3. Systemic ventricular volume overload from a persistent left-to-right shunt
  4. Right-to-left shunting through a fenestration causing chronic cyanosis in all patients

Explanation

The Fontan circulation routes systemic venous return directly to the pulmonary arteries without a subpulmonary pumping chamber. Pulmonary blood flow is therefore passive and depends on systemic venous pressure and low pulmonary vascular resistance. A fenestration may allow some right-to-left shunting, but it is not present or symptomatic in all patients.

Question 50Anatomy, Pathophysiology, and Natural History of Congenital Lesions

A 35-year-old with a large ventricular septal defect has cyanosis and pulmonary hypertension. Which pathophysiologic process best explains the cyanosis?

  1. Increased pulmonary blood flow causing pulmonary edema
  2. Right-to-left shunting from elevated pulmonary vascular resistance Correct answer.
  3. Left ventricular outflow tract obstruction
  4. Severe tricuspid regurgitation

Explanation

In Eisenmenger syndrome, chronic pulmonary overcirculation leads to progressive pulmonary vascular disease and elevated pulmonary vascular resistance. When pulmonary resistance exceeds systemic resistance, the shunt reverses to right-to-left, causing cyanosis. Pulmonary edema is more typical of left heart failure or pulmonary venous obstruction.