Pediatric Cardiology Board Review

Chapter 1. Cardiac Anatomy and Physiology

Jennifer A. Johnson and Jonathan N.Johnson

   1. A newborn infant presents with a systolic murmur heard best at the apex. An echocardiogram is diagnostic of mitral arcade. Which of the following would best describe a mitral arcade?

A. Thickened mitral valve leaflets

B. Absent/abnormal chordal insertions

C. Absent papillary muscles

D. Fused papillary muscles

E. Decreased interpapillary muscle distance

   2. A 2-day-old male infant presents with d-transposition of the great arteries (d-TGA). In the consideration for potential repair, the surgeon asks you about the coronary anatomy. Which of the following do you tell him is the most common coronary arterial abnormality in d-TGA?

A. Intramural left coronary artery

B. Left anterior descending from the right coronary artery (RCA)

C. Left circumflex from the RCA

D. Single left coronary artery

E. Single RCA

   3. A 6-month-old patient is seen with Tetralogy of Fallot (TOF). Fibrous continuity of which cardiac valves is present in the majority of patients with TOF?

A. Aortic—pulmonary

B. Aortic—tricuspid

C. Pulmonary—tricuspid

D. Tricuspid—mitral

E. Pulmonary—mitral

   4. A 2-year-old female is in the intensive care unit after repair of a ventricular septal defect and is hypotensive. In response to the decreased renal arterial pressure, which of the following hormones is released from the kidney?

A. Angiotensin II

B. Prostaglandin

C. Vasopressin

D. Norepinephrine

E. Renin

   5. A 14-year-old male undergoes a chest CT after direct chest trauma in a sporting event. He was previously asymptomatic. The radiologist calls and tells you that the patient has an abnormality of the aortic arch. Which of the following is the most likely aortic arch malformation in this patient?

A. Left aortic arch with anomalous right subclavian artery

B. Double aortic arch

C. Right aortic arch with left ductus arteriosus

D. Isolation of left pulmonary artery

E. Anomalous right pulmonary artery from ascending aorta

   6. In the mature cardiac myocyte, the majority of calcium involved in the binding of troponin-C, and thus, the initiation of myocyte contraction is stored in which cellular space?

A. Extracellular space

B. T-tubule

C. Sarcoplasmic reticulum

D. Mitochondria

E. Lysosomes

   7. A neonate is diagnosed with truncus arteriosus. Which of the following are you most likely to find regarding the morphology of the truncal valve?

A. Unicuspid

B. Bicuspid

C. Tricuspid

D. Quadricuspid

E. Pentacuspid

   8. A 12-year-old male is diagnosed with mild aortic stenosis. You suspect that he has an abnormal aortic valve. Which of the following is the most likely aortic leaflet pattern present in this patient?

A. Bicuspid valve with fusion of the right and noncoronary cusps

B. Bicuspid valve with fusion of the right and left cusps

C. Unicuspid valve with fusion of more than one cusp

D. Quadricuspid valve with a cleft of the left coronary cusp

E. Bicuspid valve with fusion of the left and noncoronary cusps

   9. Which of the following is the best anatomic hallmark of the morphologic left atrium?

A. Smooth surfaced free wall

B. Fingerlike trabeculated atrial appendage

C. Valve of fossa ovalis (septum primum)

D. Entrance of pulmonary veins

E. Connection to mitral valve

 10. Which of the following is true regarding the atrioventricular (AV) node?

A. AV nodal artery is most commonly a branch of the left coronary artery

B. AV node is positioned within triangle of Koch

C. AV node is posterior to coronary sinus

D. AV node is anterior to membranous septum

E. AV node is a subepicardial structure

 11. Which of the following is the most reliable anatomic feature that distinguishes the normal right ventricle from the left ventricle?

A. Course apical trabeculations

B. Presence of moderator band

C. Continuity between semilunar and AV valve

D. Shape of the ventricle

E. Level of insertion of AV valve at cardiac crux

 12. Which of the following factors has the greatest impact on the pressure drop across two points in the vascular system?

A. Maximum velocity of blood flow

B. Blood viscosity

C. Vessel length

D. Vessel radius

E. Vessel diameter

 13. Which of the following factors would shift the O2 dissociation curve to the left?

A. Increased temperature

B. Increased pH

C. Increased PCO2

D. Increased 2, 3-DPG

E. Increased fetal hemoglobin concentration

 14. Embryologically, where do the left pulmonary artery and the ductus arteriosus arise from?

A. Left sixth aortic arch

B. Left fourth aortic arch

C. Left sixth and fourth aortic arches, respectively

D. Left fourth and sixth aortic arches, respectively

E. Left fifth aortic arch

 15. Which coronary artery typically supplies the posteromedial papillary muscle of the mitral valve?

A. Left circumflex

B. Left anterior descending

C. Obtuse marginal

D. Right coronary

E. Conal branch

 16. Which vascular structure has the highest oxygen content in the fetal circulation?

A. Aorta

B. Umbilical vein

C. Superior vena cava

D. Umbilical artery

E. Ductus arteriosus

 17. Which of the following structures is located within the pericardium?

A. SVC-innominate vein junction

B. Pulmonary artery bifurcation

C. Transverse aortic arch

D. Hepatic vein

E. Left subclavian artery

 18. What is the ligament of Marshall?

A. The remnant of ductus arteriosus

B. The remnant of left superior vena cava

C. The remnant of ductus venosus

D. The remnant of the oblique vein of left atrium

E. The remnant of the fossa ovalis

 19. You diagnose a 2-month-old male with TOF. Which of the following are you most likely to also find on echocardiography in this patient?

A. Atrial septal defect (ASD)

B. Right aortic arch

C. Aortic stenosis

D. Coarctation of the aorta

E. Mitral valve prolapse

 20. Which of the following is the best anatomic hallmark of the morphologic right atrium?

A. Broad-based atrial appendage

B. Prominent pectinate muscles

C. Ostium of SVC

D. Ostium of IVC

E. More posterior location than LA

 21. A 10-year-old female with newly diagnosed systemic lupus erythematosus (SLE) is referred for an echocardiography. During the study, a verrucous Libman–Sacks lesion was noted. On which valve is this lesion most commonly found?

A. Aortic valve

B. Mitral valve

C. Tricuspid valve

D. Pulmonary valve

E. Eustachian valve

 22. Which is the normal location of the sinus node?

A. Subepicardial at junction of SVC and right atrial appendage

B. Subendocardial at junction of SVC and crista terminalis

C. Subendocardial within triangle of Koch

D. At junction of right atrial appendage and transverse sinus

E. Subepicardial at junction of the IVC and right atrium.

 23. You are performing an angiogram on a 5-year-old with a history of cardiac surgery. You note that the aortic arch has only two cephalic branches (Fig. 1.1). Which of the following is the most likely explanation for this finding?

Figure 1.1.

A Left vertebral artery arises from the aortic arch

B. Left common carotid artery arises from the brachiocephalic artery

C. Left subclavian artery arises from the brachiocephic artery

D. Right common carotid arises from the aortic arch

E. Right subclavian artery arises from the descending aorta

 24. What is the sinus that lies anterior to the superior vena cava and posterior to the ascending aorta and pulmonary trunk called?

A. Transverse sinus

B. Oblique sinus

C. Coronal sinus

D. Pericardial recess

E. Longitudinal sinus

 25. A 2-year-old female with a history of a ventricular septal defect presents to your office for follow-up. On examination, you hear a diastolic murmur at the apex. Echocardiography confirms that she has an infundibular or subarterial type of VSD, with aortic regurgitation. Prolapse of which aortic cusp is most likely causing the regurgitation?

A. Left

B. Right

C. Anterior

D. Septal

E. Noncoronary

 26. An overriding AV valve:

A. Has chordal attachments into both ventricles

B. Must have chordal attachments to the ventricular septal crest

C. Empties into two ventricles

D. Cannot coexist with straddling

E. Is never associated with malalignment type of VSD

 27. Which of the following is true about a straddling cardiac valve?

A. Cannot coexist with overriding

B. Is not associated with malalignment type of VSD

C. Is most commonly involving the pulmonary valve

D. Is a common component of TOF

E. Involves anomalous insertion of chordae tendineae

 28. You diagnose a neonate with asplenia syndrome. Which of the following is most likely to be present in this patient?

A. The liver is midline with two mirror-image left lobes

B. The biliary tree is patent with associated multiple gall bladders

C. Stomach position is fixed to the right side

D. Normal rotation of the bowels

E. Descending aorta and IVC are on the same side of vertebral column

 29. You diagnose a neonate with polysplenia. Which of the following is true regarding this patient?

A. The situs of abdominal viscera is almost always ambiguous

B. There are multiple spleens on both the left and right sides

C. The IVC is typically interrupted, with azygous continuation to SVC

D. Multiple gallbladders are common

E. The SVC is typically interrupted

 30. Which is the most reliable feature of the normal AV valve that distinguishes the mitral valve from the tricuspid valve?

A. Shape of the orifice

B. AV valve—semilunar valve continuity

C. Presence of septal chordal attachments

D. Level of attachment of AV valve at cardiac crux

E. Number of leaflets

 31. A neonate is diagnosed with double-outlet right ventricle (DORV). Which of the following positions of the aorta are you most likely to find (relative to the pulmonary artery)?

A. Side by side

B. Right anterior

C. Left anterior

D. Left posterior

E. Right posterior

 32. A neonate is diagnosed with pulmonary atresia/VSD. The patient undergoes a cardiac catheterization. What do you tell the interventionalist is the most common origin for systemic-to-pulmonary collaterals in this diagnosis?

A. Ascending thoracic aorta

B. Descending thoracic aorta

C. Abdominal aorta

D. Left subclavian artery

E. Coronary artery

 33. A single SA node in a normal position is typically found in which of the following?

A. Left juxtaposition of the atrial appendages

B. Right juxtaposition of the atrial appendages

C. Right atrial isomerism

D. Left atrial isomerism

E. Situs inversus of the atria

 34. What is the crescent-shaped valvular remnant at the coronary sinus ostium called?

A. Thebesian valve

B. Eustachian valve

C. Valve of the fossa ovalis

D. Chiari network

E. Valve of the SVC

 35. Mutations in which protein may cause disassociation of the intracellular cytoskeleton and the extracellular matrix in cardiac myocytes, in addition to causing muscular dystrophy?

A.α-Dystroglycan

B. Syntrophin

C. Cytoplasmic actin

D. Dystrophin

E. Caveolin

 36. From what does closure of the foramen ovale shortly after birth result directly or indirectly?

A. Endothelial release of prostaglandin

B. Endothelial release of prostacyclin

C. Smooth muscle contraction within the septum secundum

D. Postnatal decline of pulmonary vascular resistance

E. Decreased right ventricular compliance

 37. Among the following fetal venous structures, which has the lowest oxygen saturation?

A. Ductus venosus

B. Inferior vena cava

C. Left hepatic vein

D. Coronary sinus

E. Right pulmonary vein

 38. A 6-month-old infant status post repair of a complete AV canal has the following results of a blood gas:

pCO2: 36 mm Hg

HCO3: 14 mm/L

pH: 7.21

Which of the following is the acid–base abnormality present in this patient?

A. Acute respiratory alkalosis

B. Acute respiratory acidosis

C. Acute metabolic acidosis

D. Acute metabolic alkalosis

E. Chronic respiratory acidosis

 39. The direction in which blood flows through an ASD primarily is related to what?

A. Relative compliances of the LV and RV

B. Pulmonary vascular resistance

C. Systemic vascular resistance

D. Morphology of Eustachian valve

E. Redundancy of atrial septum

 40. Which of the following events is responsible for early, functional closure of the patent ductus arteriosus (PDA)?

A. Hemorrhage and necrosis in the subintimal region

B. Medial smooth muscle cell migration into the wall of the ductus

C. Equalization of pulmonary and systemic vascular resistance

D. Infolding of the endothelium

E. Thinning of the intimal layer

 41. A 12-year-old male is referred to you for a murmur. On taking the history, you find out that he is a recent immigrant from Nepal, just arriving yesterday. Which of the following are you most likely to find on a hemodynamic evaluation of this patient, compared to a patient living at sea level?

A. Elevated pulmonary artery pressure

B. Left atrial enlargement

C. Decreased LV systolic function (EF ~40%)

D. Decreased tricuspid regurgitant velocity

E. Elevated systemic blood pressure

 42. What does the formation of an ostium primum ASD result from?

A. Abnormal endocardial cushion development

B. Excessive resorption of the septum primum

C. Insufficient growth of the septum secundum

D. Abnormal resorption of the pulmonary vein

E. Abnormal rotation of the dextrodorsal conal swelling

 43. The normal left aortic arch is primarily derived from which embryologic aortic arch?

A. First (I) arch

B. Second (II) arch

C. Third (III) arch

D. Fourth (IV) arch

E. Sixth (VI) arch

 44. In the cardiac sarcomere, which of the following named feature includes the entirety of the myosin contractile elements?

A. E-line

B. I-band

C. H-zone

D. Z-disk

E. A-band

 45. The resting potential of which ion is primarily responsible for the baseline (phase 4) resting conductance of cardiac myocytes?

A. Calcium

B. Sodium

C. Potassium

D. Chloride

E. Magnesium

 46. The rapid depolarization of cardiac myocytes (phase 0) is driven by the rapid influx of which ion into the myocytes?

A. Sodium

B. Potassium

C. Chloride

D. Magnesium

E. Calcium

 47. An 8-year-old male is diagnosed with a sinus venosus ASD on echocardiography. Relative to the fossa ovalis, where would you expect to find a sinus venosus ASD?

A. Anterior and superior

B. Anterior and inferior

C. Posterior and superior

D. Posterior and inferior

E. Anterior and apical

 48. Atrial systole accounts for what percentage of ventricular filling in the normal patient?

A. <1%

B. 5%

C. 15%

D. 75%

E. 90%

 49. A 3-year-old female is diagnosed with Ebstein’s anomaly. Of the following, which additional diagnosis is most likely to be found in this patient?

A. Ventricular septal defect

B. Coarctation of the aorta

C. PDA

D. Mitral valve prolapse

E. Pulmonary stenosis

 50. Which of the following structures are specialized cell junctions between adjacent myocytes and include fascia adherens, desmosomes, and gap junctions?

A. Z-disks

B. Intercalated disks

C. Costameres

D. T-tubules

E. Sarcolemma

 51. Which of the following structures typically pass under the transverse aortic arch in the normal heart?

A. Right pulmonary artery and right bronchus

B. Left pulmonary artery and left bronchus

C. Left pulmonary artery and right bronchus

D. Right pulmonary artery and left bronchus

E. Left pulmonary artery and thoracic duct

 52. A 3-year-old girl undergoes repair of coarctation of the aorta. Post-operatively, she is able to be extubated, but develops intermittent stridor. Chest radiography is unremarkable. Which of the following is the most likely structure that was injured during the operation?

A. Left vagus nerve

B. Right recurrent laryngeal nerve

C. Left recurrent laryngeal nerve

D. Thoracic duct

E. Right vagus nerve

 53. The normal right superior vena cava is derived from which of the following embryologic structures?

A. Right anterior cardinal vein

B. Left anterior cardinal vein

C. Right vitelline vein

D. Ductus venosus

E. Left umbilical vein

 54. Which of the following embryologic aortic arches regresses and typically does not contribute to any structure in the normal neonate?

A. Left fourth arch

B. Right fourth arch

C. Left third arch

D. Left sixth arch

E. Left fifth arch

 55. Systemic arteriolar vasodilation occurs in response to:

A.Decreased pO2

B.Decreased pCO2

C.Decreased H+

D.Decreased K+

E.Decreased Mg++

 56. A term neonate presents with tachycardia, poor perfusion, and respiratory failure. The liver is enlarged on examination. Echocardiography reveals dilation of all four heart chambers. You note that the echo-calculated cardiac output is markedly elevated. Which of the following is the most likely source of the high-output cardiac failure?

A. Lower extremity arteriovenous malformation (AVM)

B. Vein of Galen malformation

C. Upper extremity AVM

D. Hepatic AVM

E. Pulmonary AVM

 57. A 14-year-old male presents with shortness of breath and progressive fatigue over the previous 2 to 3 years. He denies any chest pain, syncope, wheezing, or chronic cough. His past medical history is otherwise unremarkable. While performing an echocardiogram, you note the Doppler flow pattern in the descending aorta seen in Figure 1.2.

Figure 1.2.

You note that there is no evidence of a ductus arteriosus or aortic insufficiency, and flow to the cranial vessels is normal. Which of the following is the most likely diagnosis?

A. Ascending aorta dilation

B. Mitral regurgitation

C. Aberrant right subclavian artery from the descending aorta

D. LV-aorta tunnel

E. Anomalous RCA from the left sinus

 58. A newborn infant presents with TOF. Of the following abnormal coronary patterns, which are you most likely to find on echocardiography?

A. Intramural left coronary artery

B. Left anterior descending from the RCA

C. Left circumflex artery from the RCA

D. Single left coronary artery

E. Single RCA

 59. A 3-day-old female is diagnosed with tricuspid atresia. Which of the following great artery relationships are you most likely to find on echocardiography?

A. D-TGA

B. L-TGA

C. Normally related great arteries

D. Left anterior aorta

E. Right anterior aorta

 60. Which of the following is true regarding the morphologic left atrium in the normal heart?

A. It contains the limbus of the fossa ovalis

B. There is a large, pyramidal appendage

C. There are pectinate muscles

D. There is a prominent crista terminalis

E. There is a small, fingerlike appendage

 61. You are seeing a 4-month-old female with tricuspid atresia, d-TGA, moderate pulmonary stenosis, and a mildly restrictive ventricular septal defect. In this patient, where is the AV node most likely to be positioned?

A. Floor of the blind right atrium

B. Posteriorly behind the ostium of the coronary sinus

C. Anteriorly along the atrial septum in the right atrium

D. In the left atrium just medial to the left AV valve annulus

E. Lateral to the ostium of the IVC in the right atrium

 62. Which of the following is true regarding the right ventricle in the normal heart?

A. Has small apical trabeculations

B. Has a prominent crista terminalis

C. Has a smooth upper septal surface

D. Is a tripartite chamber

E. There is tricuspid-pulmonary continuity

 63. At 1 month of gestation in the human embryo, the pulmonary venous plexus establishes a single connection to the sinoatrial portion of the developing heart, called the common pulmonary vein. What is the fate of this structure in the normal heart?

A. Disappears, with eventual independent appearance of the four pulmonary veins

B. Is incorporated into the back wall of the left atrium

C. Is incorporated into the coronary sinus

D. Is incorporated into the wall of the right atrium

E. Becomes the supero-posterior portion of the atrial septum

 64. Migration of cardiac neural crest cells into the developing heart induces which embryologic process?

A. Rightward looping of the primitive heart tube

B. Endocardial cushion development

C. Septation of the conotruncal outflow tract

D. Septation of the atria

E. Differentiation between atria and ventricles

 65. A 14-year-old male presents with cyanosis. An echocardiogram reveals severe Ebstein’s anomaly with severe tricuspid valve regurgitation. Which of the following is the most likely cause of his cyanosis?

A. Left to right shunt at atrial level

B. Right to left shunt at ventricular level

C. Coronary fistula

D. Stenotic outflow to pulmonary arteries

E. Right to left shunt at atrial level

 66. You are called to see a cyanotic neonate in the neonatal intensive care unit. You note that the patient has an oxygen saturation of 69%. His chest x-ray shows decreased vascular markings in the lung fields. Which of the following is the most likely anatomy you will find on examination and echocardiogram?

A. Critical pulmonary stenosis

B. Truncus arteriosus

C. Total anomalous pulmonary venous return

D. Hypoplastic left heart syndrome

E. Tricuspid atresia with transposed great arteries

 67. Which of the following is true regarding fetal hemoglobin?

A.Is composed of α- and β-subunits

B. Is present in normal children until the age of 6 years

C. Is replaced by adult hemoglobin by the 38th week of gestation

D. Has a higher affinity for oxygen than adult hemoglobin

E. Has a lower affinity for oxygen than adult hemoglobin

 68. A 4-month-old infant status post repair of a ventricular septal defect has the following results of a blood gas:

pCO2: 73 mm Hg

HCO3: 25 mm/L

pH: 7.15

Which of the following is the acid–base abnormality present in this patient?

A. Acute respiratory alkalosis

B. Acute respiratory acidosis

C. Acute metabolic acidosis

D. Acute metabolic alkalosis

E. Chronic respiratory acidosis

 69. Relative to the fossa ovalis, where would you expect to find a coronary sinus ASD?

A. Anterior and superior

B. Anterior and inferior

C. Posterior and superior

D. Posterior and inferior

E. Posterior and medial

 70. Which of the following changes occurs with inspiration in the normal heart and lungs?

A.Increase in pleural pressure by 3 to 5 cm-H2O

B. Decrease in intra-abdominal pressure

C. Decreased Doppler E velocity of the tricuspid valve

D. Increased Doppler E velocity of the mitral valve

E. Increased in right ventricular stroke volume

 71. A 3-year-old female is in the ICU status post modified Fontan operation and has poor-perfusion and desaturations. When negative-pressure ventilation is instituted, her saturations improve markedly. Which of the following is the most accurate explanation for this improvement?

A. The Fontan circulation is more dependent on inspiratory increases in cardiac output compared to a normal circulation

B. Improvement in atelectasis

C. Improved flow through the Fontan fenestration

D. Associated left (systemic) ventricular dysfunction

E. The Fontan circulation is more dependent on expiratory increases in cardiac output as compared to a normal circulation

 72. A circular structure is seen on a transesophageal echocardiogram running between the left pulmonary veins and the left atrial appendage, just posterior and superior to the mitral valve. What does this structure most likely represent?

A. Membrane of cor triatriatum

B. Persistent levo-atrial cardinal vein

C. Persistence of the left horn of the sinus venosus

D. Total anomalous pulmonary venous return

E. Descending aorta

 73. Which fetal remnant delivers blood from the right and left hepatic veins to the right atrium?

A. Ductus arteriosus

B. Foramen ovale

C. Ductus venosus

D. Aortic isthmus

E. Umbilical arteries

 74. Of the following, which structure in the fetus has the least saturated blood?

A. Superior vena cava

B. Inferior vena cava

C. Patent ductus arteriosus

D. Ductus venous

E. Ascending aorta

 75. The leftward and superior position of the Eustachian valve benefits fetal life by which of the following?

A. Directing oxygen-poor blood to the tricuspid valve

B. Directing oxygen-rich blood through the foramen ovale

C. Directing oxygen-rich blood from the superior vena cava

D. Directing oxygen-rich blood from the coronary sinus

E. Directing oxygen-poor blood from the inferior vena cave

 76. In fetal life, what percent of the total cardiac output is derived from the right ventricle?

A. 10%

B. 25%

C. 40%

D. 60%

E. 90%

 77. What fetal remnant diverts right ventricle blood from the lungs to the descending aorta?

A. Ductus arteriosus

B. Foramen ovale

C. Ductus venous

D. Aortic isthmus

E. Vitelline veins

 78. On average, at what age will the normal infant’s mean pulmonary arterial pressure decrease to half of their systemic arterial pressure?

A. 2 hours of life

B. 12 hours of life

C. 1 day of life

D. 2 weeks of life

E. 2 months of life

 79. On fetal echocardiogram, you diagnosed a fetus with pulmonary atresia. All blood in their right ventricle is directed through the foramen ovale to the left atrium. What is the most likely consequence of the total cardiovascular output going through the left ventricle in this patient?

A. Aortic diameter greater than normal

B.In utero left ventricular failure

C. Under-development of the right ventricle

D. Large patent ductus arteriosus

E. Increased oxygen delivery to the brain

 80. The sarcomere is the fundamental contractile unit of striated muscle. Which contractile protein binds to calcium, allowing cross bridges to form and permitting contraction?

A. Actin

B. Myosin

C. Tropomyosin

D. Troponin I

E. Troponin C

 81. Baroreceptors are stretch receptors located in the carotid sinus and aortic arch. What is the outcome of increased arterial pressure on these receptors?

A. Decrease in afferent impulses to CNS

B. Decreased parasympathetic efferent output

C. Decreased heart rate

D. Increased sinus atrial stimulus

E. Increased cardiac output

 82. Many metabolic factors are responsible for regulating coronary arterial blood flow. Which of the following metabolic factors is derived from the breakdown of high energy phosphates?

A. Prostaglandin

B. Adenosine

C. Nitric oxide

D. Endothelin-1

E. Vascular endothelial growth factor

 83. Which arterial vessel is partially formed by the remnants of the third aortic arch?

A. Left subclavian artery

B. Brachiocephalic artery

C. Maxillary artery

D. Common carotid artery

E. Right subclavian artery

 84. In a normal 10-year-old female, left ventricular isovolumic contraction continues until what cardiac event occurs?

A. Mitral valve opens

B. Aortic valve opens

C. Passive atrial filling

D. Increased ventricular volume

E. Aortic pressure greater than left ventricular pressure

 85. What is the primary mechanism by which the myocardium compensates for increased oxygen demand?

A. Increased oxygen extraction

B. Increased coronary blood flow

C. Increased parasympathetic stimulus

D. Decreased adenosine release

E. Decreased cardiac output

 86. In resting conditions, what percentage of oxygen in coronary blood flow is extracted by the myocardium?

A. 10%

B. 20%

C. 40%

D. 70%

E. 90%

 87. A 3-month-old female is brought to the emergency room with cyanosis, tachypnea, and irritability. Her mother states that she has a heart condition, but does not know any specific information regarding her cardiac history. What acute event is causing this patients cyanosis?

A. Increased pulmonary blood flow

B. Increased right to left shunting

C. Increased systemic vascular resistance

D. Decreased pulmonary vasculature resistance

E. Increased left to right shunting

 88. Which of the following conditions would accurately describe a 4-month-old female with un-repaired TOF, who has severe right ventricular outflow obstruction?

A. Absent femoral pulses

B. Qp > Qs

C. Congestive heart failure

D. Arterial desaturation

E. Left to right shunting at ventricular level

 89. The most common coexisting anomaly associated with d-TGA is?

A. Mitral valve abnormalities

B. Coarctation of the aorta

C. Leftward juxtaposition of the atrial appendages

D. Ventricular septal defect

E. Left ventricular outflow obstruction

 90. A neonate is diagnosed with d-TGA. You hear a loud, single second heart sound. What is the explanation behind this finding?

A. Ventricular septal defect

B. Anterior position of aorta

C. Pulmonary atresia

D. Severe aortic stenosis

E. Pulmonary vascular obstructive disease

 91. A 2-week-old male has an echocardiogram performed for a murmur. You note that the patient has moderate mitral valve stenosis and a single papillary muscle. Which of the following is the correct anatomical description of this patient’s left AV valve?

A. Parachute mitral valve

B. Supravalvar mitral web

C. Congenitally stenotic mitral valve

D. Mitral arcade

E. Mitral valve prolapse

 92. When assessing a neonate with hypoplastic left heart syndrome, what other abnormal anatomic feature is most commonly seen?

A. Tricuspid stenosis

B. Anomalous pulmonary venous return

C. Ventricular septal defect

D. Coarctation of the aorta

E. Persistent left superior vena cava

 93. What is the most common location of the pulmonary artery in patients with truncus arteriosus?

A. Main pulmonary artery arises from the truncus

B. Branch pulmonary arteries arise independently from posterior sides of the truncus

C. Branch pulmonary arteries arise independently from lateral sides of the truncus

D. Branch pulmonary arteries arise from descending aorta

E. Main pulmonary artery arises from innominate artery

 94. A newborn is diagnosed with hypoplastic left heart syndrome. Of the following, which anatomic form of HLHS is the most common?

A. Aortic valve atresia with patent mitral valve

B. Aortic valve atresia with mitral valve atresia

C. Aortic valve stenosis with patent mitral valve

D. Aortic valve stenosis with mitral valve stenosis

E. Aortic valve atresia with mitral valve regurgitation

 95. You diagnose a neonate with truncus arteriosus. It appears that this patient has a single pulmonary artery. Which artery is most likely to be absent?

A. Left pulmonary artery

B. Right pulmonary artery

C. The pulmonary artery on the same side of the aortic arch

D. The pulmonary artery on the opposite side of the aortic arch

E. Both left and right pulmonary arteries

 96. What is the most common anatomic abnormality associated with coarctation of the aorta?

A. Ventricular septal defect

B. Parachute mitral valve

C. Bicuspid aortic valve

D. Subaortic stenosis

E. Tricuspid valve stenosis

 97. Which of the following is true regarding T-tubules?

A. Do not participate in excitation–contraction coupling

B. Are a component of intercalated disks

C. Envelop myofibrils at the level of the A-band

D. Do not contain calcium ion channels

E. Are a continuation of the sarcolemma

 98. A 2-year-old male presents with cyanosis. Which of the following is true regarding the diagnosis of cyanosis in this patient?

A. This patient most likely has an ASD

B. The best indicator of cyanosis in this patient is the nail beds

C. The patient most likely has rib notching on chest radiography

D. To visualize cyanosis, the patient has to have at least 5 g/dL of deoxygenated hemoglobin

E. This patient most likely has a PDA.

 99. A 17-year-old male is involved in a head-on motor vehicle accident. In the emergency department, the physicians suspect he has pericardial tamponade secondary to myocardial rupture. Which of the following is the most likely chamber for the rupture to occur?

A. Right ventricle

B. Left ventricle

C. Right atrium

D. Left atrium

E. Atrial appendage

100. In a normal 4-year-old female, a typical left ventricular isovolumic relaxation continues until what cardiac event occurs?

A. Mitral valve opens

B. Aortic valve opens

C. Passive atrial filling

D. Increased ventricular volume

E. Aortic pressure greater than left ventricular pressure

Answers

1. ANSWER: B.  The mitral arcade, or hammock mitral valve, is characterized by absent or abnormal chordal insertions, and the leaflet edges may connect directly to the papillary muscles. The papillary muscles themselves are often small and abnormal. The leaflet edges are often thickened and rolled. Owing to this direct insertion of the leaflets to the papillary muscles, the leaflets are relatively tethered and display poor coaptation. Mitral regurgitation is most common, although a functional mitral stenosis can also occur.

2. ANSWER: C  Patients with d-TGA most commonly have normal coronary anatomy (67%), but ~15% of patients will have an anomalous circumflex coronary artery arising from the right coronary. The next most common abnormalities are a single RCA and an inverted right coronary and left circumflex (inverted origins of the RCA and LCx but normal origin of the LAD from the anterior facing sinus).

3. ANSWER: B  In ~80% of patients with TOF, there is fibrous continuity between the tricuspid and the aortic valves. In the remainder, there is a rim of tissue along the posterior and inferior rim of the defect, preventing aortic-tricuspid continuity.

4. ANSWER: E  The juxtaglomerular apparatus of the kidney, in response to lower renal perfusion pressures, will secrete renin. Renin induces cleavage of angiotensinogen to angiotensin I. This is then converted to angiotensin II by angiotensin-converting enzyme (ACE) in the lungs and vasculature. Angiotensin II will induce vasoconstriction and stimulate ADH (vasopressin) secretion.

5. ANSWER: A  The most common abnormality of the aortic arch is an anomalous right subclavian artery from a left aortic arch. This occurs in ~0.5% of the general population and is usually asymptomatic. The diagnosis is often made at autopsy, or during imaging for another condition. It is seen commonly in patients with Down syndrome who have congenital heart disease.

6. ANSWER: C  In mature myocytes, the sarcoplasmic reticulum stores the most important source of calcium involved in the initiation of myocyte contraction. Calcium enters the myocyte during the action potential through L-type voltage-gated calcium channels. This calcium then activates the calcium-release channel (also called the ryanodine receptor), causing release of calcium from the sarcoplasmic reticulum. In immature cardiac myocytes, the function and organization of the sarcoplasmic reticulum is not yet to mature levels, and activation is more dependent on flow through the L-type calcium channels.

7. ANSWER: C  The truncal valve in truncus arteriosus is most commonly tricuspid (~70%), but can also be quadricuspid (~20%), bicuspid (~10%), pentacuspid (<1%), or unicommissural (<1%). The valve is in fibrous continuity with the mitral valve in all patients, but can also rarely be in fibrous continuity with the tricuspid valve.

8. ANSWER: B  Of patients with a bicuspid aortic valve, by far the most common form is fusion of the right and left cusps (75%). The next most common pattern are patients with fusion of the right and noncoronary cusps, followed by those with left and noncoronary cusp fusion. Fusion of more than one cusp can result in a unicuspid valve.

9. ANSWER: C  All the options listed above are anatomic features of the morphologic left atrium, but the best and most specific hallmark is the valve of the fossa ovalis. In contrast, one of the hallmarks of the right atrium is the limbus of the fossa ovalis.

10. ANSWER: B  The AV node is located in the subendocardium within the triangle of Koch. It is adjacent to the central fibrous trigone (the central fibrous body). The borders of the triangle of Koch include the septal tricuspid annulus, the coronary sinus ostium, and tendon of Todaro. The AV node gives rise to the bundle of His, which then travels through the central fibrous body.

11. ANSWER: E  The most reliable feature that distinguishes the right ventricle from the left ventricle is the level of insertion of the respective AV valve at the cardiac crux. The pattern of trabeculations and the shape of the ventricle are not reliable in many forms of congenital heart disease. Continuity between AV and semilunar valves may be useful but is not as reliable as the level of AV valve insertion.

12. ANSWER: D  This question refers to the Poiseuille–Hagen relationship, where the resistance R between two points is a function of pressure and flow. This is ultimately described by the equation R = (8*L*η)/(π*r4), where the radius is raised to the fourth power (L = length of the vessel, η = viscosity).

13. ANSWER: B  The hemoglobin-oxygen dissociation curve is key to understand the relationship between pO2 and oxygen saturations. Increasing the pH (alkalosis), decreasing temperature, and decreasing 2, 3-DPG will shift the curve to the left; likewise, acidosis, increased temperature, and increasing 2, 3-DPG shift the curve to the right.

14. ANSWER: A  The pulmonary arteries and ductus arteriosus arise from the left sixth aortic arch. The majority of the aortic arch arises from the left fourth aortic arch, while the right fourth aortic arch gives rise to the proximal portion of the right subclavian artery.

15. ANSWER: D  While the anterolateral papillary muscle typically has a dual blood supply from the left anterior descending and circumflex coronary arteries, the posteromedial papillary muscle is typically solely supplied by the RCA.

16. ANSWER: B  The umbilical vein is the structure that brings blood from the placenta to the fetus and has the highest oxygen content within the fetal circulation. The blood then passes from the umbilical vein, through the ductus venosus and left hepatic vein into the atrium.

17. ANSWER: B  The pericardium encloses the great arteries superiorly at the junction between the ascending aorta and the transverse aortic arch, the pulmonary artery just beyond the bifurcation, and the superior vena cava just below the azygous vein. The pericardium also encloses the most superior portion of the inferior vena cava inferiorly and the proximal pulmonary veins posteriorly.

18. ANSWER: B  The left superior vena cava persists in a minority of individuals. When present, it often provides a source of venous return through the coronary sinus into the right atrium. The remnant of the left superior vena cava is termed the ligament of Marshall.

19. ANSWER: A  An ASD or a patent foramen ovale is present in over 80% of patients with TOF. Abnormalities of the left side of the heart are rare in patients with TOF. A right aortic arch occurs in ~25% of patients.

20. ANSWER: D  Since some patients with congenital heart disease may have absence of the typical left atrial (valve of the fossa ovalis) and right atrial (limbus of the fossa ovalis) characteristics, the next best marker for the right atrium is the ostium of the IVC. The suprahepatic IVC nearly always connects directly to the right atrium. This rule is particularly useful in the evaluation of complex heterotaxy patients.

21. ANSWER: B  The classic valve abnormality of SLE is the Libman–Sacks endocarditis lesion, a verrucous, nonbacterial lesion. These are most commonly found on the left-sided valves and predominantly on the mitral valve. They appear in ~10% of patients newly diagnosed with SLE. On echocardiography, they are irregular vegetations, <0.5 cm in diameter, on the valve or chordal apparatus.

22. ANSWER: A  The SA node is located subepicardially, unlike the AV node that is subendocardial. It is found at the border of the embryonic atrium and the sinus venosus, in the sulcus terminalis. Blood supply is derived from the sinus nodal artery.

23. ANSWER: B  In ~10% of normal individuals, the left common carotid artery originates from the brachiocephalic artery. This has been called the “bovine arch, ” and only the brachiocephalic artery and left subclavian artery will directly arise from the aorta. Option A will result in four vessels arising from the aorta and occurs in ~5% of individuals. Option C is rare, and options D and E will result in more than two branches from the arch.

24. ANSWER: A  The transverse sinus includes the intra-pericardial space between the great arteries anterosuperiorly and the atrial walls posteroinferiorly. It can be visualized in some post-operative patients as the echo-dark space around the aortic sinus in the parasternal short-axis echocardiographic image, if fluid is present in the sinus. The oblique sinus refers to the sinus between the posterior left atrium and the reflections of the great veins (superior vena cava and pulmonary veins).

25. ANSWER: B  The subarterial type of VSD comprises ~5% of VSDs at autopsy, but is significantly more common in Asian populations. Owing to the location of the VSD, there is deficiency of the support structure below the aortic valve, with subsequent herniation of the right coronary leaflet through the defect. This may also occur in some patients with perimembranous defects.

26. ANSWER: C  The categorical definition of an overriding AV valve is one that empties into two ventricles. It is always associated with a malalignment ventricular septal defect. If there are also anomalous insertions of the chordae tendineae into the contralateral ventricle, then the valve is considered to be overriding and straddling.

27. ANSWER: E  The definition of a straddling AV valve is one that involves anomalous insertion of the chordae tendineae. It is important to identify pre-operatively as it may prevent the surgeon from attempting certain repairs. There has to be a VSD, but it may or may not be a malalignment-type VSD.

28. ANSWER: E  In most asplenia patients, the descending aorta and IVC will travel on the same side of the vertebral column. There is a high incidence of bowel malrotation, and the stomach can be located on the left, right, or midline. There is typically only one gall bladder, but it can be variable in position, depending on the site of the liver. Biliary atresia is uncommon. The liver is most commonly midline with two mirror-image right lobes.

29. ANSWER: C  In polysplenia, the multiple spleens are typically located all on the same side of the vertebral column as the stomach. The gall bladder is typically single, but patients may have concurrent biliary atresia. The abdominal situs is variable and can be normal, mirror-image, or indeterminate. The IVC commonly is interrupted with azygous continuation to the SVC.

30. ANSWER: D  The level of attachment of the AV valve is crucial in determining both the specific type of AV valve as well as ventricular morphology. The mitral valve typically inserts into the cardiac crux between 0 and 8 mm/m2 higher than the tricuspid valve. Exceptions to this include Ebstein anomaly, where >8 mm/m2 difference exists, and partial AV canal defects or double-inlet ventricles, where no difference between the valvular insertions exist. The other options are helpful in determining valve type, but are not as reliable in patients with congenital heart disease.

31. ANSWER: A  The most common aortic-pulmonary positions in DORV are the side-by-side configurations (aorta to the right of the pulmonary artery), accounting for ~2/3 of DORV patients. The aorta may arise more anterior (right-anterior aorta) or posterior (right-anterior aorta) in some patients or may be leftward and anterior to the pulmonary artery.

32. ANSWER: B  The most common site of origin for systemic-to-pulmonary collaterals in pulmonary atresia with VSD is the descending thoracic aorta. They can also arise (albeit more rarely) from the subclavian arteries, abdominal aorta or its branches or from the coronary arteries. Over half of these collaterals have some form of stenosis.

33. ANSWER: B  In patients with right atrial isomerism, bilateral sinus nodes can be encountered. In left atrial isomerism, the sinus node can be absent or malpositioned. In left-sided juxtaposition of the atrial appendages, the sinus node is often displaced anteriorly or inferiorly. Left-juxtaposition is associated more with abnormal ventriculo-arterial connections, while right-sided juxtaposition is more commonly associated with simpler lesions, like ASDs.

34. ANSWER: A  This valvular remnant is known as the Thebesian valve. The Eustachian valve is located at the entrance of the inferior vena cava. Chiari network is a fine, filamentous structure that represents persistence of the valve of the sinus venosus and typically extends from the crista terminalis to the Eustachian or Thebesian valves. They direct blood flow from the SVC and IVC through the foramen ovale to the left atrium. In normal patients, this regresses to form the crista terminalis, a ridge in the right atrium separating the sinus venosus portion of the right atrium from the muscular right atrium.

35. ANSWER: D  Dystrophin is a protein that links the extracellular matrix and cytoplasmic actin, providing a vital link between extracellular and intracellular structures of the myocyte. Mutations in the gene encoding for this protein cause muscular dystrophy and are a known cause of dilated cardiomyopathy. Caveolin and syntrophin are proteins that are also involved in the linking of intracellular and extracellular structures and cause long QT syndrome and SIDS when mutated. Cytoplasmic actin and the dystroglycan complex are mutated in some patients with dilated cardiomyopathy.

36. ANSWER: D  The majority of changes in the post-natal circulation occur as a result of a rapid and large drop in pulmonary resistance, as well as the sudden absence of the placental circulation. Closure of the patent foramen ovale, unlike the ductus arteriosus and ductus venosus, is largely passive, due to the changes in blood return to the left and right atria post-natally and thus a higher left atrial pressure than right atrial pressure.

37. ANSWER: D  The least saturated blood in the fetus is in the coronary sinus and the superior vena cava, the oxygen having been used by the head and brain or the myocardium. The inferior vena cava, left hepatic vein, and ductus venosus will all receive some or all their flow from the umbilical vein, and thus will not be at maximal desaturation.

38. ANSWER: C  The patient has an acute metabolic acidosis, as evidenced by the low pH, relatively normal pCO2, and low bicarbonate.

39. ANSWER: A  The primary determinant of the direction of blood flow through an ASD is the relative compliances of the left and right ventricles. In the otherwise normal patient, the right ventricle will be more compliant than the left ventricle, with less resistance to filling from the right atrium, and thus left to right shunting across the ASD. The vast majority of patients with ASDs have a relatively normal pulmonary resistance.

40. ANSWER: B  Immediately after birth, in the first stage of closure, contraction and migration of medial smooth muscle cells into the wall of the PDA produce increased wall thickness and luminal protrusion of the thickened intima. This results in functional closure of the PDA and occurs within 12 hours of birth in normal full-term infants. The second stage of closure includes infolding of the endothelium, disruption of the elastic lamina, and necrosis of the subintima. There is eventual replacement of muscle and endothelium with fibrotic tissue, producing the ligamentum arteriosum.

41. ANSWER: A  Children living at elevation have been shown to have higher mean pulmonary artery pressures as compared to those living at sea level. This increase in pulmonary pressure is even more exacerbated with exercise. This may have a role in explaining the relatively increased risk of persistence of the PDA in children living at altitude.

42. ANSWER: A  A primum ASD is located anteriorly to the fossa ovalis in the inlet portion of the septum. Failure of the endocardial cushions to develop is the embryologic basis behind AV canal defects, including primum ASDs.

43. ANSWER: D  The majority of the aortic arch arises from the left fourth aortic arch, while the right fourth aortic arch gives rise to the proximal portion of the right subclavian artery. The pulmonary arteries and ductus arteriosus arise from the left sixth aortic arch.

44. ANSWER: E  The A-band, bisected by the M-line, contains all the myosin contractile elements of the sarcomere. The I-band, bisected by the Z-disk, contains purely actin elements of the sarcomere. The H-zone is a central subsection of the A-band that does not include the areas of myosin-actin overlap.

45. ANSWER: C  The IK1 potassium current is the dominant resting conductance of the myocyte. It keeps the myocyte negatively polarized around −85 mV, until an action potential arrives to activate the cell into phase 0.

46. ANSWER: A  When an action potential arrives at the cardiac myocyte, the cardiac sodium channels open, resulting in a rapid depolarization of the myocyte (phase 0). Once this primary depolarization has occurred, the sodium channels are inactivated in a time-dependant manner. Potassium and calcium conductance takes over at that point, providing the prolonged phase 1 and phase 2 depolarization required to achieve muscle contraction. Mutations in the sodium channel gene, SCN5A, may cause type 3 long QT syndrome or Brugada syndrome.

47. ANSWER: C  Relative to the fossa ovalis, a sinus venosus ASD will be posteriorly and superiorly placed. The defect is typically secondary to the absence of the usual rim of tissue between the right pulmonary veins and the right atrium. As such, it occurs commonly in the presence of anomalous right upper pulmonary venous return.

48. ANSWER: C  The majority of blood fills the ventricle in a passive manner during diastole, but an additional amount of blood flows across the AV valves after atrial contraction in late diastole or atrial systole (the atrial kick). This amount is estimated in the normal patient to be between 10% and 30% of ventricular filling. Flow dynamics are highly dependent on ventricular function, both systolic and diastolic, and atrial filling may increase or decrease depending on the physiologic milieu. The atrial kick may be absent in patients with heart block or atrial arrhythmias.

49. ANSWER: E  By far, the most common additional abnormality seen in patients with Ebstein’s anomaly is an ASD, seen in >80% of patients. The next most common associated abnormality is pulmonary stenosis, followed by a ventricular septal defect. The degree of RV outflow obstruction is critical to determine before designing treatment plans in the neonate with severe Ebstein’s anomaly. Functional or true pulmonary atresia may be present in the neonate.

50. ANSWER: B  Intercalated disks are junctions between adjacent myocytes. They link the myofibrils to costameres (which are intracellular protein complexes), transmitting force from the sarcomere to the extracellular matrix and adjacent myocytes. They also function to link the cytoplasmic actin filaments to the cytoskeleton and connect intermediate filaments between adjacent cells. T-tubules are a continuation of the sarcolemma, enveloping myofibrils at the level of the Z-disks, and are important for rapid activation of the entire myocyte after arrival of an action potential. The sarcolemma refers to the plasma membrane of the myocyte.

51. ANSWER: D  The trachea divides into left and right bronchi just after passing the aortic arch, with the left bronchus heading under the arch. The pulmonary artery at its bifurcation is leftward of the ascending aorta. The right pulmonary artery heads under the arch to get to the right lung. The left pulmonary artery heads more posteriorly over the left bronchus.

52. ANSWER: C  The left recurrent laryngeal nerve is a branch of the vagus nerve that travels inferiorly around the aortic arch before traveling superiorly to innervate muscles in the larynx. The right recurrent laryngeal nerve takes a similar course but loops around the right subclavian artery. Injury to the left recurrent laryngeal nerve is possible during surgical manipulation of the aortic arch and often results in post-operative hoarseness and stridor.

53. ANSWER: A  The right anterior cardinal vein and right common cardinal vein give rise to the right superior vena cava. The left anterior cardinal vein typically regresses but may be persistent as a left superior vena cava. The ductus venosus remnant is termed the ligamentum venosum, and the umbilical vein remnants include the round ligament of the liver.

54. ANSWER: E  The fifth aortic arch is typically rudimentary and does not usually develop into any known vessels in the normal neonate. It is not even present in many embryo specimens. Rare cases have been reported of persistence of the fifth arch, which can either be asymptomatic or be associated with other cardiac findings. If the fifth arch persists, but there is interruption of the normal fourth arch, the patient may present with a clinical picture of coarctation.

55. ANSWER: A  Specific tissues are able to regulate local blood flow in response to changing metabolic demands. A decrease in the pO2 causes a systemic arteriolar vasodilation, as the local tissues attempt to get more oxygen delivery through increased volume of flow. Similarly, increasing pCO2, increasing H+ (acidosis), or increasing K+ will cause local vasodilation. Some tissues will also release adenosine as a vasodilator in response to increased oxygen demand.

56. ANSWER: B  The vein of Galen malformation is the most common hemodynamically significant extracardiac AVM in neonates. It affects male infants three times more commonly than female infants. The infants commonly present with high-output cardiac failure soon after birth. A bruit can often be heard through the fontanelle. Other types of cerebral AVMs may also be present similarly, but the vein of Galen malformation is the most common.

57. ANSWER: D  The Doppler pattern shows evidence of large flow reversals in the abdominal aorta. This can be caused by a large ductus arteriosus, severe aortic insufficiency, or an intracranial AVM such as a vein of Galen malformation. Another potential cause of this is a large LV-aorta tunnel, as occurred in this patient. LV-aorta tunnels typically arise above the right aortic sinus of Valsalva.

58. ANSWER: B  Approximately 5% of patients with TOF have an origin of the left anterior descending artery arising from the RCA. This coronary then takes a course anterior to the right ventricular outflow tract. This is an important anomaly to rule out, as the coronary’s course can prevent the surgeon from using a transannular patch to open the right ventricular outflow tract. Approximately 10% to 15% of patients will have an accessory LAD (large conal branch). Other coronary patterns are rare, occurring in <5% of patients.

59. ANSWER: C  The most common form of tricuspid atresia is type 1, or tricuspid atresia with normally related great arteries. The pulmonary outflow can vary from pulmonary atresia to widely patent pulmonary outflow without stenosis. The associated ventricular septal defect is expectedly larger in the presence of a widely patent pulmonary outflow and smaller in patients with pulmonary stenosis. Approximately 70% to 80% of patients with tricuspid atresia have normally related great arteries.

60. ANSWER: E  The left atrial free wall typically has a small, finger-like appendage in the normal heart. The appendage rests over the left AV groove and covers the proximal portion of the left circumflex coronary artery. All other answers in this question are features of the right atrium.

61. ANSWER: A  The AV node in tricuspid atresia is on the floor of the blind right atrium. The bundle of His then courses onto the crest of the intraventricular septum (muscular) and runs posterior to the VSD rim. This is important in the eventual repair or palliation of tricuspid atresia, in that care needs to be taken with any surgical procedure involving the VSD for fear of inducing heart block.

62. ANSWER: D  The right ventricle is composed of the inlet, trabecular, and outlet regions. There is typically a coarse septal surface, with large apical trabeculations. The tricuspid and pulmonary valves are not in continuity in the normal patient.

63. ANSWER: B  The common pulmonary vein is the initial connection between the pulmonary venous plexus and the heart. The vein typically has four (or more) primary feeding veins, which eventually become the left and right upper and lower pulmonary veins. The common pulmonary vein is eventually incorporated into the back wall of the atrium so that the individual pulmonary veins connect independently to the atrium.

64. ANSWER: C  The heart tube derived from the primary heart field is the embryologic basis for formation of the primitive ventricle and atrium. The primary heart field cells ultimately form the left ventricle and bilateral atria. The secondary heart field consists of cells that migrate and expand into cardiac chambers using the “scaffold” of the primary heart field. These secondary heart field cells eventually form the majority of the right ventricle and conotruncal outflow. Migration of cardiac neural crest cells into the outflow tract after the rightward looping of the heart tube causes septation of the outflow tract into aorta and pulmonary segments and patterns the aortic arch branches into their bilateral, symmetric state (especially the third, fourth, and sixth arches).

65. ANSWER: E  Most patients with Ebstein’s anomaly will also be present with an ASD or patent foramen ovale. Patients with Ebstein’s anomaly and cyanosis often have right to left shunting at atrial level. This cyanosis will often worsen with exercise.

66. ANSWER: A  This patient is presenting with cyanosis and decreased pulmonary blood flow as evidenced by the lack of vascular markings in the lung fields. Critical pulmonary stenosis can present in this manner. All other options more commonly present with cyanosis and increased pulmonary vascularity.

67. ANSWER: D  Fetal hemoglobin has a higher affinity for oxygen as compared to adult hemoglobin and is composed of α- and γ-subunits. Adult hemoglobin meanwhile is composed of α- and β-subunits. The fetal hemoglobin has to have a higher affinity for oxygen in order for transport of oxygen across the placenta to be achieved. In the normal newborn, fetal hemoglobin has been replaced by adult hemoglobin by the age of 3 months.

68. ANSWER: B  The patient has an acute respiratory acidosis, as evidenced by the low pH, elevated pCO2, and normal bicarbonate. After the acute period of a respiratory acidosis, the bicarbonate will typically begin to increase to compensate and bring the pH closer to normal values.

69. ANSWER: B  Relative to the fossa ovalis, which lays in a relatively midline position in the atrial septum, a coronary sinus ASD will be inferior and anteriorly placed, at the typical site of the coronary sinus ostium. It is typically seen in association with unroofing of the coronary sinus and a persistent left SVC.

70. ANSWER: E  With inspiration, there is a fall in pleural pressure and a rise in intra-abdominal pressure. These changes lead to increased right-sided venous return and increased RV stroke volume. Doppler E velocity across the tricuspid valve is increased (~5% to 10%), while the Doppler E velocity across the mitral valve is slightly decreased (~5% to 10%).

71. ANSWER: A  Up to 1/3 of the cardiac output in the Fontan patient is directly attributable to the passive work of breathing. Patients with a Fontan circulation may poorly tolerate positive pressure ventilation for this reason, as they are unable to drop intrathoracic pressure sufficiently to allow adequate increases in forward flow. Several investigators have reported success in ventilating patients with cuirass negative pressure ventilation.

72. ANSWER: C  The circular structure seen in this location most commonly represents a dilated coronary sinus, due to a persistent left superior vena cava, which is the remnant of the left horn of the sinus venosus. This can be mistaken for the descending aorta, which should be seen more posteriorly outside the pericardium. The left SVC runs posteriorly along the left atrium before joining the coronary sinus in the left AV groove.

73. ANSWER: C  The ductus venosus receives blood flow from the hepatic veins and umbilical vein and delivers it to the right atrium. After birth the ductus venosus becomes the ligamentum venosum.

74. ANSWER: A  The superior vena cava drains unoxygenated blood from the upper body to the right atrium. The inferior vena cava carries blood from the lower body and the placenta. The patent ductus arteriosus carries mixed oxygenated blood from the pulmonary artery to the descending aorta. The ductus venosus carries mixed blood from the hepatic veins to the inferior vena cava. The ascending aortic arch supplies the most oxygen-rich blood to heart and brain. The superior vena cava and coronary sinus have the lowest oxygen saturations of all vascular pathways in the fetus.

75. ANSWER: A  The least oxygenated blood from the superior vena cava and coronary sinus are directed through the tricuspid valve to the right ventricle. The leftward and superior position of the Eustachian valve directs 95% of blood flow caudally from the superior vena cava away from the foramen ovale and toward the tricuspid valve. Right ventricular outflow ejects to the pulmonary artery and preferentially through to the descending aorta, where it passes through the umbilical artery to the placenta to be oxygenated.

76. ANSWER: D  In the fetus, ~60% of total fetal cardiac output is derived from the right ventricle, while 40% is being derived from the fetal left ventricle.

77. ANSWER: A  The patent ductus arteriosus carries mixed oxygenated blood from the pulmonary artery to the descending aorta. The superior vena cava drains unoxygenated blood from the upper body to the right atrium. The inferior vena cava carries blood from the lower body and the placenta. The ductus venosus carries mixed blood from the hepatic veins and umbilical vein to the inferior vena cava.

78. ANSWER: C  Approximately 24 hours after birth, a normal infant’s mean pulmonary arterial blood pressure should decrease to about half of systemic arterial pressure. It takes anywhere from 2 to 6 weeks for the pulmonary arterial blood pressure to reach adult levels.

79. ANSWER: A  All blood from the right side of the heart is directed through the foramen ovale and joins the pulmonary venous return to the left atrium. The total cardiac venous output is ejected to the ascending aorta. This is around double the normal blood flow through the aorta, which is typically increased in diameter.

80. ANSWER: E  Calcium binds to troponin C, changing the tertiary structure of troponin C and other troponin subunits. This allows tropomyosin to shift positions and allows myosin and actin binding, leading to muscle cell contraction.

81. ANSWER: C  Baroreceptors are found in each carotid sinus and aortic arch. These receptors respond to stretch of the arterial walls and send impulses to the brain. This stimulation results in a decreased blood pressure, by a decrease in heart rate and vasodilation.

82. ANSWER: B  Adenosine is produced from the breakdown of ATP, which cannot be regenerated at times of low oxygen tension. Therefore, at times of low oxygen tension, AMP is made and then further broken down into adenosine, which causes coronary artery vasodilation. Nitric oxide induces the cyclic guanosine monophosphate that causes muscle relaxation. Endothelin-1 causes tonic vasoconstriction. Prostaglandin induces smooth muscle relaxation.

83. ANSWER: D  The first aortic arch forms part of the maxillary axillary, while the second aortic arch forms portions of the stapedial arteries. The third aortic arch forms the common carotid artery and the proximal portion of the internal carotid artery.

84. ANSWER: B  At end diastole, the LV filling is complete, and the mitral valve closes. There is a period of isovolumic contraction, after which the aortic valve opens secondary to a higher pressure in the aorta compared to the LV.

85. ANSWER: B  Owing to high baseline oxygen extraction levels by the myocardium, the coronary oxygen tension is low (~20–25 mm Hg). An increase in oxygen demand is supplied by increasing coronary blood flow and not by changes in oxygen extraction.

86. ANSWER: D  The myocardium extracts 60% to 75% of oxygen from coronary blood flow. The majority of other organs will only extract ~30% in the normal patient. Coronary sinus saturations are typically the lowest in the circulation.

87. ANSWER: B  Hypercyanotic spells consist of abrupt onset of cyanosis, hypoxemia, dyspnea, and agitation. Events usually occur after the age of 2 months. Crying and agitation lead to increased pulmonary vascular resistance, with increased right to left shunting and decreased pulmonary blood flow. Infundibular spasm may also be involved in the limitation of RV outflow to the pulmonary arteries.

88. ANSWER: D  With severe RVOT obstruction and ventricular-level right-to-left shunting, this patient will most likely present with arterial desaturation. The Qp will be significantly less than the Qs, and the patient will not be in heart failure. Shunting at the ventricular level will be mostly right to left, contributing to the cyanosis.

89. ANSWER: D  A ventricular septal defect occurs in 40% to 45% of patients with d-TGA. The majority of VSDs are of the perimembranous, muscular, or malalignment type. Isolated LV outflow obstruction occurs in ~5% of patients. Coarctation, arch hypoplasia, or interrupted arch occurs in ~5% of patients. Leftward juxtaposition of the atrial appendages occurs in 2% to 5% of d-TGA patients. Approximately 20% of patients have been shown to have mitral valve abnormalities at autopsy; however, these are rarely functionally significant. Of these, cleft mitral valve is likely the most common.

90. ANSWER: B  The aorta and pulmonary artery are often located in an anterior-posterior position to each other, causing the narrow mediastinum and “egg-on-a-string” image seen on some chest x-rays. Owing to the anterior aorta, the second heart sound is often single and loud.

91. ANSWER: A  A mitral valve in which all the chordal attachments connect to a single papillary muscle is called a parachute mitral valve. There is also a variant with attachments to two distinct papillary muscles, but with most attachments occurring to one of the papillary muscles. The chordae may be shortened and thickened. If the valve leaflets insert directly onto the papillary muscle, it would then be called a mitral arcade.

92. ANSWER: D  80% of neonates with hypoplastic left heart syndrome will have evidence of a localized coarctation of the aorta, in addition to the typical ascending aorta hypoplasia and left ventricular hypoplasia. Anomalous pulmonary venous return and persistence of a left SVC each occur in <5% of patients. Right AV valve dysplasia can occur in <30% of patients and occurs more commonly in patients with patent mitral valves.

93. ANSWER: A  50% to 70% of patients with truncus arteriosus have type I, with the main pulmonary artery arising from the left postero-lateral aspect of the truncus right above the truncal valve. 25% to 45% of patients have type II, with the branch pulmonary arteries arising from the posterior surface of the truncus. 5% to 10% of patients have type III truncus, with the branch pulmonary arteries arising from the lateral sides of truncus. In type IV truncus, the branch pulmonary arteries arise from descending aorta.

94. ANSWER: B  Aortic atresia with mitral valve atresia occurs in 36% to 46% of patients with HLHS, compared to 13% to 26% of patients with aortic stenosis with mitral stenosis. 20% to 29% of patients have aortic atresia with a patent mitral valve.

95. ANSWER: C  In TOF, when a pulmonary artery is absent, the one affected is most commonly on the opposite side of the aortic arch. In contrast, in patients with truncus arteriosus, the absent pulmonary artery is typically on the same side of the aortic arch. This is a key distinction between absent pulmonary arteries in these two entities.

96. ANSWER: C  A bicuspid aortic valve may be seen in up to 80% of patients with coarctation of the aorta. Many investigators consider the combined findings as an indication of a true “aortopathy, ” which is now proven by genetic linkage studies. Approximately half of the patients with coarctation have a “simple” coarctation, implying normal intra-cardiac anatomy (other than the bicuspid aortic valve), while the other half have associated anomalies (VSD being the most common).

97. ANSWER: E  T-tubules are a continuation of the sarcolemma, enveloping myofibrils at the level of the Z-disks, and are important for rapid activation of the entire myocyte after arrival of an action potential (excitation–contraction coupling). They are the site of numerous L-type calcium channels, which provide the initial calcium flow into the cell during excitation. Intercalated disks are junctions between adjacent myocytes. They link the myofibrils to costameres (which are intracellular protein complexes), transmitting force from the sarcomere to the extracellular matrix and adjacent myocytes. They also function to link the cytoplasmic actin filaments to the cytoskeleton and connect intermediate filaments between adjacent cells.

98. ANSWER: D  In order for the examiner to be able to visualize true cyanosis, there must be at least 5 g/dL of deoxygenated hemoglobin. Thus, in a patient with anemia, a relatively low oxygen saturation may not result in the expected clinical cyanosis. The best indicator of cyanosis is the tongue due to the rich vascular supply and lack of pigmented cells. Rib notching is rare in a 2-year-old even in the presence of a significant coarctation of the aorta. ASD at 2 years of age will rarely cause significant right-to-left shunting.

99. ANSWER: A  The right ventricle, being thin walled and the most anterior structure, is more commonly ruptured than the left ventricle. Ventricular rupture overall is more common than atrial rupture. Multiple ruptures are not uncommon, such as a combination of ventricular and aortic rupture. Survival is poor in patients with myocardial rupture, and surgical exploration is required emergently. If there is atrial rupture, the most common site of rupture is the atrial appendage.

100. ANSWER: A  At end systole, LV ejection is complete, and the aortic valve closes. This begins the period of isovolumic relaxation, with a subsequent drop in LV pressure. At the end of this period, the mitral valve opens, allowing filling of the ventricle due to lower pressures in the ventricle.