Block 13: Cardiology Board Review: q & A



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Block 13: Cardiology Board Review: Q & A
1. A 15-year-old patient is brought to your office with a complaint of chest pain. She had been healthy until 3 days ago, when she developed a fever. The pain is precordial, referred to the epigastrium, and exacerbated by deep breathing and coughing. She refuses to lie down and prefers to sit leaning forward.
Of the following, the MOST likely expected finding on electrocardiography is

A. elevation of the S-T segments

B. first-degree heart block

C. pre-excitation with a delta wave

D. tall peaked T waves

E. T-wave flattening


Preferred Response: A
Chest pain in children and adolescents is a common problem for which patients and parents frequently seek medical care. The causes of chest pain in the pediatric population are varied and can be considered by organ systems: musculoskeletal, respiratory, gastrointestinal, psychological, and cardiac. Among the musculoskeletal causes are chest wall strain, trauma, costochondritis, and the precordial catch syndrome. Respiratory causes include asthma, pneumonia, pneumothorax, pneumomediastinum, and chronic cough. Chest pain may result from gastritis, esophagitis, or indigestion. Psychogenic processes, including anxiety, fear, and attention-seeking behaviors, may cause or exacerbate chest pain. Perhaps the most common causes of chest pain in pediatrics are those referred to as idiopathic. Such a diagnosis often is given to the patient who presents with a 1- to 2-week history of intermittent, brief, sharp, or stabbing pain that is not associated with exercise or exertion.
The cardiac causes of chest pain are important to recognize because they can be associated with significant morbidity and mortality. Pericardial pain (resulting from inflammation and often associated with pericarditis), angina and myocardial ischemia, arrhythmias, or aortic dissection may cause chest pain.
The common causes of pericarditis are viral, inflammatory, and rheumatologic. The typical pain of pericarditis frequently is substernal, positional, and can be severe. Patients often prefer to sit leaning forward, as described for the girl in the vignette, and may refuse to lie down. The pain worsens with deep inspiration, coughing, or movement of the upper torso. Because the pericardium is inflamed, pericardial effusion may occur in affected patients, which may lead to pericardial tamponade. Some, but not all, pericardial effusions in pericarditis have the associated finding of a friction rub noted on auscultation. The absence of a rub does not exclude pericardial effusion or pericarditis.
Electrocardiographic findings can include S-T segment elevation, low voltage, or in cases of large pericardial effusion, electrical alternans. The latter finding is a beat-to-beat variation in voltage that likely results from the pendular motion of the heart in the effusion.
First-degree heart block is not likely in pericarditis. Pre-excitation is seen in patients who have Wolff-Parkinson-White syndrome rather than pericarditis. Abnormalities of the T waves usually implicate an electrolyte abnormality. Tall, peaked T waves are seen with hyperkalemia, and flattened T waves are a nonspecific finding that may be seen with hypokalemia or certain ventricular strain patterns.
2. Yesterday, you received a call from the newborn nursery that they were referring to you a term infant who was being discharged at 4 days of age. The female newborn’s birthweight was 3.3 kg and the delivery was by repeat cesarean section. Findings on physical examination at discharge, including heart rate, respiratory rate, and blood pressure, were normal. Her lungs were clear, and no murmurs were noted. She was breastfeeding without difficulty. Today, her mother calls to tell you that she is difficult to awaken, pale, and breathing much more rapidly than she was in the hospital nursery. She has had one wet diaper in the last 12 hours. When you meet them in the emergency department, you note that the infant has cool extremities, weak pulses, and lethargy.
Of the following, the MOST likely cause of this newborn’s condition is

A. aortic coarctation

B. atrioventricular septal (canal) defect

C. tetralogy of Fallot

D. transposition of the great arteries

E. ventricular septal defect


Preferred Response: A
The newborn described in the vignette has had an acute change in behavior, with diminished feeding as well as clinical signs of diminished systemic perfusion and shock. Despite the normal birth history and findings at hospital discharge, congenital heart disease may be a cause of the shock.
In fact, the presentation is most consistent with a left heart obstructive disorder, such as aortic stenosis, coarctation of the aorta, or hypoplastic left heart syndrome. In such patients, tachypnea is caused by pulmonary congestion that results from decreased filling of the failing left heart. A gallop rhythm may be audible on auscultation, due to filling of the noncompliant left ventricle. The tachypnea exacerbates the poor feeding resulting from the infant’s inability to generate a prolonged suck while maintaining nasal breathing. When coupled with increased losses of water through the respiratory system, such poor intake leads to dehydration and decreased urine output. The lethargy exhibited by the infant in the vignette may reflect decreased perfusion to the brain and may be exacerbated by the metabolic acidosis that results from inadequate tissue perfusion.
Immediate management of this critically ill patient includes the administration of prostaglandin E to re-establish patency of the ductus arteriosus. Definitive therapy involves surgery to repair the coarctation.
Atrioventricular septal (canal) defects and ventricular septal defects are both left-to-right shunting lesions that become apparent after birth when the pulmonary vascular resistance normally begins to decrease. These shunting lesions are characterized by increased blood flow into the pulmonary artery because the direction of shunt is always from the high-resistance circuit to the low-resistance circuit (normally the systemic to pulmonary system). If the shunt volume is large, signs and symptoms of congestive heart failure ensue, but these almost always manifest over the first weeks, if not months, after birth.
Tetralogy of Fallot is the most common of the cyanotic congenital heart diseases and typically presents with the murmur of pulmonary blood flow obstruction. Because the degree of obstruction is progressive, patients may present with normal oxygen saturation or cyanosis resulting from desaturated blood moving right to left at the ventricular septal defect. Transposition of the great arteries is a cyanotic heart disease that presents within hours of birth in most cases. Neither tetralogy of Fallot nor transposition presents with shock.
3. A 5-day-old child is brought to the emergency department because he has been difficult to arouse over the last 6 hours. His parents report that he has not been interested in feeding today and that he has been breathing rapidly and with a grunting noise. On physical examination, the infant’s heart rate is 185 beats/min, respiratory rate is 80 breaths/min, and blood pressure is 55/40 mm Hg. A pulse is palpable in the right brachial region, but not in the feet. All of his extremities are cool and mottled, with a capillary refill of more than 2 seconds.
Of the following, the MOST appropriate next step is to

A. arrange for echocardiography at the first appointment in the morning

B. initiate a furosemide infusion

C. initiate a prostaglandin infusion

D. obtain a computed tomography scan of the head

E. obtain a lumbar puncture


Preferred Response: C
The clinical presentation of the newborn described in the vignette suggests left heart obstruction with a closing ductus arteriosus. The discrepancy in pulses is consistent with a critical aortic coarctation. Appreciation of the importance of the patent ductus arteriosus in maintaining systemic blood flow in the newborn who has severe left heart obstruction such as hypoplastic left heart syndrome (HLHS) and critical aortic coarctation requires a clear understanding of normal fetal shunting patterns.
In the normal heart, the right atrium and right ventricle deliver desaturated blood to the organ of oxygenation. In the fetus, this organ is the placenta, and its fetal blood supply is via the umbilical artery that arises from the fetal descending aorta. The ductus arteriosus provides a fetal shunting pathway that allows the right side of the fetal heart to deliver desaturated blood to the organ of oxygenation by shunting this blood away from the high-resistance pulmonary arteries and into the descending aorta. This direction of flow occurs in part because fetal pulmonary vascular resistance (with fluid-filled developing lungs) is slightly higher than fetal systemic vascular resistance, and the placenta is a low-resistance circuit.
At birth, when the lungs expand with air and the placenta is removed from the circulation, pulmonary vascular resistance decreases and systemic vascular resistance increases. This leads to a reversal of flow across the ductus arteriosus (from the system into the pulmonary circuit). Over the subsequent hours and days, the ductus arteriosus begins the process of spontaneous closure.
The foramen ovale is an important fetal shunt that allows the relatively oxygenated blood returning from the placenta to cross from the right atrium into the left atrium prenatally. In so doing, the blood that has the highest oxygen content is directed to the coronary and cerebral circulations. Patency of the foramen in utero results from a slightly higher pressure in the right atrium than the left, because very little blood (~10% of the combined fetal cardiac output) returns to the left atrium from the lungs. The pressure difference “pushes” the flap of the foramen into the left atrium, creating the “hole” and allowing right-to-left blood flow. At birth, when the lungs expand and the entire cardiac output is directed into the lungs, pressure in the left atrium increases, rising slightly above that in the right atrium. When this occurs, the flap of the foramen is pushed back against the atrial septum and the “hole” is closed.
Left heart obstruction in the newborn often has a dramatic presentation that may include shock, cardiovascular collapse, and death if not recognized in a timely manner. HLHS and coarctation of the aorta are the two most common forms of left heart obstructive congenital heart disease that present in the first few postnatal days. HLHS is characterized by underdevelopment of the entire left side of the heart with a small or atretic mitral valve; a small, non-useful left ventricle; and a small or atretic aortic valve. As a result, nearly all of the blood flow returning from the lungs is diverted to the right atrium through the foramen ovale because the left heart simply cannot accommodate it. The right heart then delivers blood to the lungs through the pulmonary arteries and to the system through right-to-left shunting across the ductus arteriosus.
In severe aortic coarctation, the left heart is of sufficient size to handle the cardiac output returning from the lungs, but narrowing in the aortic arch leads to diminished flow to the distribution of the descending aorta and a progressive pressure load on the left ventricle. With patency of the ductus arteriosus, the right heart can provide blood flow to the descending aorta through right-to-left shunting across the ductus. In both HLHS and coarctation of the aorta, perfusion of the aorta with right ventricular output maintains systemic perfusion and minimizes the ischemia and subsequent metabolic acidosis that otherwise would ensue when the ductus arteriosus constricts.
In such cases, patency of the ductus arteriosus can be maintained by prostaglandins such as PGE1 administered as a continuous intravenous infusion. If the patency of the foramen ovale is not sufficient to maintain adequate decompression of the left atrium, a balloon atrial septostomy, a catheter procedure to enlarge the atrial communication, can be performed.
For the patient described in the vignette, the best management is to increase the systemic perfusion by maintaining the ductus arteriosus with the infusion of PGE1. Echocardiography is an important component of the diagnosis and management of patients who have suspected congenital heart disease, but its performance should not delay therapeutic options such as the initiation of the PGE1. Furosemide, a diuretic, has no beneficial role for the infant whose systemic perfusion is limited by a closing ductus arteriosus. Lumbar puncture and computed tomography scan of the head are not indicated as initial management.
4. You are seeing a 2-week-old girl in your office for a health supervision visit. Her parents report that she is eating well and has good weight gain. On physical examination, you note a strong right brachial pulse, but you cannot feel pulses in the right or left femoral region. As you explain the diagnosis to the parents, they ask you about long-term complications following repair of her condition.
Of the following, the MOST likely long-term complication for this child is

A. frequent pulmonary infections

B. hypertension

C. neurodevelopmental delay

D. poor exercise performance

E. renal dysfunction


Preferred Response: B
The girl described in the vignette has the classic physical findings of coarctation of the aorta: an easily palpable pulse in the right arm (blood flow origin proximal to the obstruction) and an absent pulse in the lower extremities (blood flow origin distal to the obstruction). Coarctation of the aorta refers to an anatomic obstruction or narrowing in the aorta that can be localized as a ridge of tissue, formed as a discrete ring of tissue, or collarlike with length forming a segment of aortic hypoplasia. Less-than-normal blood flow through the aortic arch during fetal life may result in hypoplasia of the arch and promote the likelihood of coarctation developing, which forms the basis for the association between aortic stenosis (and other left heart obstructions) and coarctation.
The incidence of coarctation is approximately 1 in 2,300 live births, making it one of the most common types of congenital heart disease encountered by the pediatrician. It occurs with greater frequency in females who have Turner syndrome (45,X), in whom the incidence may be as high as 15%. Patients who have coarctation have a high incidence of associated congenital heart disease, the most common of which are a patent ductus arteriosus, bicuspid aortic valve, and mitral valve abnormalities.
Physical examination in the patient who has coarctation usually reveals a discrepant pulse quality between the right radial and the femoral or dorsalis pedis. Patients also may come to attention with hypertension noted on examination. A systolic ejection murmur of low intensity is audible at the base and axilla and left interscapular region and usually is loudest over the back.
Neonates who have significant coarctation may present with signs and symptoms of congestive heart failure and inadequate perfusion of the gut and lower body. Ultimately, affected patients can present in cardiogenic shock because the left ventricle is unable to pump against the afterload imposed by the coarctation.
Coarctation that presents in the symptomatic neonate should be repaired surgically. However, even with aggressive and excellent surgical repair, re-coarctation can occur as the child grows. In addition, patients who undergo surgical repair of aortic coarctation have a higher incidence of hypertension at long-term follow-up and should be followed closely for this complication. In contrast to the long-term risk for hypertension, patients who have undergone an uncomplicated neonatal repair of aortic coarctation do not have an increased rate of pulmonary infections, neuro-developmental delay, or poor exercise performance. Although congenital heart disease can be associated with renal abnormalities in some cases, routine coarctation and its repair are not associated with the long-term complication of renal dysfunction.
5. You are evaluating a 15-year-old boy who will be attending sports camp in the summer. He tells you that he is very athletic, has no trouble keeping up with his peers during physical activities, and, in fact, has less fatigue with activities than most of his friends. On physical examination, he is well-developed and comfortable. The first and second heart sounds are normal. There is a systolic click at the upper right sternal border as well as a 3/6 systolic ejection murmur at the upper right sternal border. There is a thrill in his suprasternal notch. Diastole is clear, and his pulses are normal in all extremities.
Of the following, the MOST likely cause of this patient’s signs and symptoms is

A. aortic stenosis

B. atrial septal defect

C. patent ductus arteriosus

D. pulmonary stenosis

E. ventricular septal defect


Preferred Response: A
The patient described in the vignette has the typical findings of aortic stenosis, which often is associated with a systolic click that results from the abnormal structure and function of the valve. The click occurs with opening of the thickened semilunar valve leaflets during systole. In contrast to the normal thin and flexible valve leaflets, those of the stenotic aortic valve have an accentuated sound that is referred to as an opening click. The murmur of aortic stenosis results from systolic blood flow from the left ventricle across the abnormally narrowed orifice of the

aortic valve. The narrowing yields a diminished valve area through which the stroke volume crosses, creating turbulence that is noted during auscultation as a systolic ejection murmur and typically is heard best over the aortic valve and ascending aorta. On the chest wall, these structures lie beneath the right sternal border, with extension up toward the right clavicle. The murmur often radiates into the neck. A thrill may be appreciated in the suprasternal notch, with the turbulent blood flow in the transverse aortic arch being palpable in some patients.


Pulmonary stenosis is associated with a systolic ejection click that does not change with position, but the accompanying murmur is heard best at the upper left sternal border, with radiation into the back and axillae.
The murmur associated with an atrial septal defect is not from the blood flow across the atrial septum, which usually is not turbulent and at low pressure. Rather, the systolic murmur created by an atrial septal defect is caused by a relative pulmonary stenosis because the left-to-right atrial shunt and resulting increased right ventricular volume must cross the pulmonary valve. In contrast to pulmonary valve stenosis, there is no structural abnormality of the pulmonary valve and, thus, no systolic click.
A patent ductus arteriosus typically produces a continuous murmur that is characterized as having a "machinery" quality and usually is loudest at the left infraclavicular area. It is continuous because of the constant flow between the systemic and pulmonary circulation, with the higher systemic than pulmonary vascular resistance throughout the cardiac cycle and no valve to separate the two in the structure of the ductus.
The murmur of a ventricular septal defect is typically holosystolic because the left-to-right shunt at the ventricular level begins with the onset of systole, even before the aortic and pulmonary valves open. When the ventricular septal defect is small, it produces a high-pitched murmur, heard along the sternal border, and the second heart sound is normal, with no change in its normal physiologic splitting.
6. You are evaluating a 2-month-old girl as part of a routine health maintenance visit. Her mother tells you that she has no trouble feeding and is gaining weight like her previous children. Her precordial examination demonstrates a mild lift. The first and second heart sounds are normal. There is a systolic click at the upper left sternal border as well as a 3/6 systolic ejection murmur at the upper left sternal border with radiation to the axillae. Diastole is clear, and her pulses are normal in all extremities.
Of the following, the MOST likely cause of this patient’s signs and symptoms is

A. aortic stenosis

B. atrial septal defect

C. patent ductus arteriosus

D. pulmonary stenosis

E. ventricular septal defect


Preferred Response: D
The infant described in the vignette has typical findings of pulmonary stenosis, which often is associated with a systolic click resulting from the abnormal structure and function of the pulmonary valve. The click is caused by the opening of the thickened valve leaflets during systole. In contrast to the normal thin and flexible semilunar valve leaflets, those of the stenotic pulmonary valve have an accentuated sound that is referred to as an opening click. The murmur of pulmonary stenosis results from systolic blood flow from the right ventricle across the abnormally narrowed orifice of the pulmonary valve. The narrowing yields a diminished valve area through which the stroke volume crosses, creating turbulence. Such turbulence is noted during auscultation as a systolic ejection murmur and typically is heard best over the pulmonary valve and main pulmonary artery. On the chest wall, these structures lie beneath the left sternal border, with extension cephalad toward the left clavicle. Frequently, the murmur radiates into the back and the axillae as the sound of turbulence follows the course of the branch pulmonary arteries.
Aortic stenosis also is associated with a systolic ejection click that does not change with position, but the accompanying murmur is heard best at the upper right sternal border, with radiation into the neck.
The murmur associated with an atrial septal defect is not from the blood flow across the atrial septum, which usually is nonturbulent and at low pressure. Rather, the systolic murmur created by an atrial septal defect is the result of a relative pulmonary stenosis as the left-to-right atrial shunt and resulting increased right ventricular volume must cross the pulmonary valve. In contrast to pulmonary valve stenosis, there is no structural abnormality of the pulmonary valve and, thus, no systolic click.
Patent ductus arteriosus typically produces a continuous murmur characterized as having a "machinery" quality that is usually loudest at the left infraclavicular area. It is continuous because of the constant flow between the systemic and pulmonary circulation resulting from the higher systemic vascular resistance compared with the pulmonary vascular resistance throughout the cardiac cycle and the lack of a valve to separate the two circulations.
The murmur of a ventricular septal defect typically is holosystolic because the left-to-right shunt at the ventricular level begins with the onset of systole, even before the aortic and pulmonary valves open. When the ventricular septal defect is small, it produces a high-pitched murmur, heard along the sternal border, and a normal second heart sound without a change in its normal physiologic splitting.
7. You are called to the newborn nursery to evaluate a 2-hour-old male who was born at term. The pregnancy was uncomplicated, but meconium staining was noted at delivery. The baby weighs 3.8 kg, is afebrile, and has a heart rate of 165 beats/min and a respiratory rate of 70 breaths/min. You note tachypnea and hyperpnea with clear breath sounds, no murmurs, and strong distal pulses. His oxygen saturation in room air is 68%. You place a nonrebreather mask to deliver an Fio2 of 1.0. After 5 minutes, the oxygen saturation is 72%.
Of the following, the BEST explanation for the findings of the hyperoxia test is

A. meconium aspiration syndrome

B. persistent pulmonary hypertension of the newborn

C. pneumonia

D. retained fetal lung liquid syndrome

E. transposition of the great arteries


Preferred Response: E
Most commonly, the practitioner is alerted to hypoxemia in the newborn by the finding of a low oxygen saturation value. Among the various causes of abnormal oxygenation in the newborn are pulmonary pathologies, congenital cardiovascular malformations, persistent pulmonary hypertension of the newborn, and disturbances of the hematologic and metabolic systems. Right-to-left shunting can be thought of as a diversion of desaturated blood away from the lungs and to the systemic circulation. This can occur because blood does not perfuse the ventilated portions of the lung (intrapulmonary right-to-left shunting). Intrapulmonary shunting resulting from infection such as pneumonia, pneumothorax, retained fetal lung liquid, and pulmonary prematurity is the most frequently encountered reason for desaturation in a newborn.
Conversely, abnormal oxygenation can result from the situations in which the desaturated blood does not perfuse the pulmonary artery from the heart (intracardiac right-to-left shunting) or is diverted from the pulmonary circuit through the ductus arteriosus (extracardiac right-to-left shunting). Examples of these pathologies include pulmonary atresia, transposition of the great arteries, tricuspid atresia, and pulmonary hypertension.
Whether the cause of the desaturation is intrapulmonary, intracardiac, or extracardiac right-to- left shunting, cyanosis (blue, maroon, or purple discoloration of the skin) is likely to be present. Typically, clinicians discern cyanosis in patients who have oxygen saturations of less than 85%, although it may be apparent to some when the saturation is 90% or less. If cyanosis is suspected in the newborn, cyanotic heart disease must be considered.
It is reasonable to place the patient in a high-oxygen atmosphere (near FiO2 of 1.0) to determine if the high-dose oxygen can overcome the shunting. If the degree of cyanosis improves and oxygen saturations become normal, the problem likely is intrapulmonary shunting rather than cyanotic heart disease. If hyperoxia does not lead to increased oxygen saturation and higher PaO2 (=150 torr), cyanotic congenital heart disease should be considered and the infant should undergo further cardiac evaluation.
The newborn described in the vignette has cyanosis but no murmurs. His tachypnea and hyperpnea (deep breathing) represent the physiologic response to hypoxemia. His saturation improves slightly with the delivery of high-dose oxygen. Transposition of the great arteries is the best explanation for the infant's hypoxemia. No amount of oxygen delivered to the patient's alveoli can improve oxygenation of the pulmonary blood flow because the pulmonary blood flow in transposition already is well saturated. The neonate remains desaturated until oxygenated blood from the left atrium adequately crosses the atrial septum to be delivered to the system through the aorta. In contrast, the oxygenation defect associated with meconium aspiration syndrome, persistent pulmonary hypertension of the newborn, pneumonia, and retained fetal lung liquid syndrome is improved with high-dose oxygen delivery to the alveoli.
8. You are treating a 4-month-old infant who was born with tetralogy of Fallot. Her mother brings her to the clinic because she has had diarrhea and fever since the previous evening. On physical examination, the infant is irritable and has cyanosis and a heart rate of 180 beats/min.
Of the following, the finding that is MOST consistent with a tetralogy spell is

A. clubbing of the digits

B. hepatomegaly

C. inability to hear a murmur

D. oxygen saturation of 75% in room air

E. S3 gallop rhythm


Preferred Response: C
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