,2 A child with a history of a large ventricular septal defect repaired in infancy now
presents with exercise intolerance and a new continuous murmur.
Echocardiography reveals a small shunt at the level of the ascending aorta. Which
of the following is the most likely diagnosis?
A) Patent ductus arteriosus
B) Aortopulmonary window
C) Coronary cameral fistula
D) Ruptured sinus of Valsalva aneurysm
Answer: B
Rationale: An aortopulmonary window is a rare congenital defect that may be missed
or develop after surgical repair of VSD due to septal malalignment. It presents with
a continuous murmur and a left-to-right shunt at the great artery level. PDA is distal
to the left subclavian artery, while coronary fistulas and ruptured sinus of Valsalva
have different auscultatory and echocardiographic findings.
3 In a patient with hypertrophic cardiomyopathy, which of the following
hemodynamic findings best distinguishes obstructive from non-obstructive
disease?
A) Left ventricular end-diastolic pressure
B) Presence of a dynamic left ventricular outflow tract gradient
C) Degree of diastolic dysfunction
D) Mitral regurgitation severity
Answer: B
Rationale: The hallmark of obstructive HCM is a dynamic LVOT gradient, often
provoked by Valsalva or exercise, due to systolic anterior motion of the mitral valve.
Non-obstructive HCM lacks this gradient. While diastolic dysfunction and MR are
common, they do not define obstruction. LVEDP may be elevated in both forms.
4 A patient with complete transposition of the great arteries (d-TGA) status post
arterial switch operation presents with new-onset exertional chest pain and
ST-segment depression on exercise stress test. Which of the following is the most
likely cause?
A) Right ventricular outflow tract obstruction
B) Neoaortic root dilation with aortic regurgitation
C) Coronary ostial stenosis
D) Pulmonary vein stenosis
Answer: C
,Rationale: Coronary ostial stenosis is a known late complication after the arterial
switch operation, due to translocation of the coronary arteries and can cause
myocardial ischemia. While RVOT obstruction and neoaortic root dilation can
occur, they do not typically present with exertional chest pain and ST changes.
Pulmonary vein stenosis is not a typical complication of ASO.
5 A 4-year-old child presents with a heart rate of 220 bpm, narrow QRS
tachycardia, and no discernible P waves. Adenosine terminates the tachycardia.
Which of the following is the most likely mechanism?
A) Atrioventricular reentrant tachycardia using a concealed accessory pathway
B) Atrioventricular nodal reentrant tachycardia
C) Atrial flutter with 2:1 conduction
D) Automatic ectopic atrial tachycardia
Answer: A
Rationale: In a young child, the most common cause of paroxysmal supraventricular
tachycardia is AVRT, typically via a concealed accessory pathway. AVNRT is less
common in children under 5 years. Atrial flutter and ectopic atrial tachycardia would
have different P wave morphologies and may not terminate with adenosine; atrial
flutter is often seen in structurally abnormal hearts.
6 A patient with a single ventricle physiology (hypoplastic left heart syndrome)
status post Fontan procedure develops protein-losing enteropathy. Which of the
following is the most appropriate initial medical therapy?
A) Prednisone
B) Sildenafil
C) Spironolactone
D) Subcutaneous unfractionated heparin
Answer: D
Rationale: Protein-losing enteropathy after Fontan is a serious complication with
high mortality. Subcutaneous heparin is a first-line therapy that may improve
enteropathy by stabilizing the endothelial glycocalyx. Corticosteroids are
second-line, sildenafil is used for elevated pulmonary vascular resistance, and
spironolactone is not specifically effective.
7 In fetal echocardiography, which Doppler finding is most indicative of critical
aortic stenosis with evolving hypoplastic left heart syndrome?
A) Reversed flow in the transverse aortic arch
B) Elevated middle cerebral artery peak systolic velocity
, C) Monophasic mitral valve inflow
D) Retrograde flow in the ductus venosus
Answer: A
Rationale: In critical aortic stenosis, the left heart cannot supply the systemic
circulation, leading to retrograde flow in the aortic arch (from the ductus arteriosus)
to perfuse the head and neck vessels. This finding indicates severe left heart
obstruction and is associated with evolution to HLHS. Elevated MCA PSV indicates
anemia, monophasic mitral inflow is seen in restrictive filling, and reversed ductus
venosus flow indicates right heart failure.
8 A patient with pulmonary atresia with intact ventricular septum and a hypoplastic
right ventricle undergoes a right ventricular outflow tract stent placement. Which
of the following is the primary hemodynamic goal of this intervention?
A) Reduce right ventricular systolic pressure
B) Increase pulmonary blood flow
C) Promote right ventricular growth
D) Decrease right atrial pressure
Answer: C
Rationale: In PA/IVS, the right ventricle is often severely hypoplastic. Stenting the
RVOT provides a source of pulmonary blood flow and, more importantly, creates a
pressure load that promotes right ventricular growth, potentially allowing eventual
biventricular repair. Reducing RV pressure is not the primary goal; in fact, RV
pressure remains high. The stent does increase pulmonary blood flow, but the key
rationale is RV growth.
9 Which of the following electrocardiographic findings is most characteristic of
arrhythmogenic right ventricular cardiomyopathy (ARVC) in a pediatric patient?
A) Epsilon wave in leads V1-V3
B) Right bundle branch block
C) Left axis deviation
D) Prolonged QT interval
Answer: A
Rationale: Epsilon waves are a specific, though not sensitive, finding in ARVC,
representing delayed depolarization of the right ventricular myocardium. They are
seen in the right precordial leads (V1-V3). RBBB is common but nonspecific, left
axis deviation is not characteristic, and prolonged QT is seen in LQTS, not ARVC.
presents with exercise intolerance and a new continuous murmur.
Echocardiography reveals a small shunt at the level of the ascending aorta. Which
of the following is the most likely diagnosis?
A) Patent ductus arteriosus
B) Aortopulmonary window
C) Coronary cameral fistula
D) Ruptured sinus of Valsalva aneurysm
Answer: B
Rationale: An aortopulmonary window is a rare congenital defect that may be missed
or develop after surgical repair of VSD due to septal malalignment. It presents with
a continuous murmur and a left-to-right shunt at the great artery level. PDA is distal
to the left subclavian artery, while coronary fistulas and ruptured sinus of Valsalva
have different auscultatory and echocardiographic findings.
3 In a patient with hypertrophic cardiomyopathy, which of the following
hemodynamic findings best distinguishes obstructive from non-obstructive
disease?
A) Left ventricular end-diastolic pressure
B) Presence of a dynamic left ventricular outflow tract gradient
C) Degree of diastolic dysfunction
D) Mitral regurgitation severity
Answer: B
Rationale: The hallmark of obstructive HCM is a dynamic LVOT gradient, often
provoked by Valsalva or exercise, due to systolic anterior motion of the mitral valve.
Non-obstructive HCM lacks this gradient. While diastolic dysfunction and MR are
common, they do not define obstruction. LVEDP may be elevated in both forms.
4 A patient with complete transposition of the great arteries (d-TGA) status post
arterial switch operation presents with new-onset exertional chest pain and
ST-segment depression on exercise stress test. Which of the following is the most
likely cause?
A) Right ventricular outflow tract obstruction
B) Neoaortic root dilation with aortic regurgitation
C) Coronary ostial stenosis
D) Pulmonary vein stenosis
Answer: C
,Rationale: Coronary ostial stenosis is a known late complication after the arterial
switch operation, due to translocation of the coronary arteries and can cause
myocardial ischemia. While RVOT obstruction and neoaortic root dilation can
occur, they do not typically present with exertional chest pain and ST changes.
Pulmonary vein stenosis is not a typical complication of ASO.
5 A 4-year-old child presents with a heart rate of 220 bpm, narrow QRS
tachycardia, and no discernible P waves. Adenosine terminates the tachycardia.
Which of the following is the most likely mechanism?
A) Atrioventricular reentrant tachycardia using a concealed accessory pathway
B) Atrioventricular nodal reentrant tachycardia
C) Atrial flutter with 2:1 conduction
D) Automatic ectopic atrial tachycardia
Answer: A
Rationale: In a young child, the most common cause of paroxysmal supraventricular
tachycardia is AVRT, typically via a concealed accessory pathway. AVNRT is less
common in children under 5 years. Atrial flutter and ectopic atrial tachycardia would
have different P wave morphologies and may not terminate with adenosine; atrial
flutter is often seen in structurally abnormal hearts.
6 A patient with a single ventricle physiology (hypoplastic left heart syndrome)
status post Fontan procedure develops protein-losing enteropathy. Which of the
following is the most appropriate initial medical therapy?
A) Prednisone
B) Sildenafil
C) Spironolactone
D) Subcutaneous unfractionated heparin
Answer: D
Rationale: Protein-losing enteropathy after Fontan is a serious complication with
high mortality. Subcutaneous heparin is a first-line therapy that may improve
enteropathy by stabilizing the endothelial glycocalyx. Corticosteroids are
second-line, sildenafil is used for elevated pulmonary vascular resistance, and
spironolactone is not specifically effective.
7 In fetal echocardiography, which Doppler finding is most indicative of critical
aortic stenosis with evolving hypoplastic left heart syndrome?
A) Reversed flow in the transverse aortic arch
B) Elevated middle cerebral artery peak systolic velocity
, C) Monophasic mitral valve inflow
D) Retrograde flow in the ductus venosus
Answer: A
Rationale: In critical aortic stenosis, the left heart cannot supply the systemic
circulation, leading to retrograde flow in the aortic arch (from the ductus arteriosus)
to perfuse the head and neck vessels. This finding indicates severe left heart
obstruction and is associated with evolution to HLHS. Elevated MCA PSV indicates
anemia, monophasic mitral inflow is seen in restrictive filling, and reversed ductus
venosus flow indicates right heart failure.
8 A patient with pulmonary atresia with intact ventricular septum and a hypoplastic
right ventricle undergoes a right ventricular outflow tract stent placement. Which
of the following is the primary hemodynamic goal of this intervention?
A) Reduce right ventricular systolic pressure
B) Increase pulmonary blood flow
C) Promote right ventricular growth
D) Decrease right atrial pressure
Answer: C
Rationale: In PA/IVS, the right ventricle is often severely hypoplastic. Stenting the
RVOT provides a source of pulmonary blood flow and, more importantly, creates a
pressure load that promotes right ventricular growth, potentially allowing eventual
biventricular repair. Reducing RV pressure is not the primary goal; in fact, RV
pressure remains high. The stent does increase pulmonary blood flow, but the key
rationale is RV growth.
9 Which of the following electrocardiographic findings is most characteristic of
arrhythmogenic right ventricular cardiomyopathy (ARVC) in a pediatric patient?
A) Epsilon wave in leads V1-V3
B) Right bundle branch block
C) Left axis deviation
D) Prolonged QT interval
Answer: A
Rationale: Epsilon waves are a specific, though not sensitive, finding in ARVC,
representing delayed depolarization of the right ventricular myocardium. They are
seen in the right precordial leads (V1-V3). RBBB is common but nonspecific, left
axis deviation is not characteristic, and prolonged QT is seen in LQTS, not ARVC.
