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ABP Pediatric Cardiology study materials
ABP Pediatric Cardiology study resources

ABP Pediatric Cardiology practice questions

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Question 1Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which congenital heart defect is the most common overall?

  1. Tetralogy of Fallot
  2. Patent ductus arteriosus
  3. Ventricular septal defect Correct answer.
  4. Atrial septal defect

Explanation

Ventricular septal defects account for roughly one-third of congenital heart defects and are the most frequently diagnosed lesion in infancy. Many small muscular defects close spontaneously, while larger defects may require intervention.

Question 2Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

In an uncomplicated secundum atrial septal defect, which chamber is volume overloaded?

  1. Right ventricle Correct answer.
  2. Left atrium
  3. Left ventricular chamber
  4. Aortic root

Explanation

A left-to-right shunt at the atrial level increases filling of the right atrium and right ventricle, producing right ventricular volume overload. The left atrium decompresses into the right atrium, so it is usually not dilated.

Question 3Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which medication is used to promote closure of a hemodynamically significant patent ductus arteriosus in a preterm infant?

  1. Indomethacin Correct answer.
  2. Propranolol
  3. Furosemide
  4. Alprostadil

Explanation

Indomethacin inhibits cyclooxygenase and lowers prostaglandin E2 levels, causing constriction of the ductal smooth muscle. Ibuprofen is used similarly; alprostadil has the opposite effect and keeps the ductus open.

Question 4Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which feature is part of the classic tetralogy of Fallot?

  1. Mitral stenosis
  2. Atrial septal defect
  3. Pulmonary stenosis Correct answer.
  4. Left ventricular hypertrophy

Explanation

The four components of tetralogy of Fallot are a ventricular septal defect, right ventricular outflow tract obstruction, an overriding aorta, and right ventricular hypertrophy. Pulmonary stenosis is the common form of right ventricular outflow tract obstruction.

Question 5Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

In dextro-transposition of the great arteries, which structure arises from the right ventricle?

  1. Pulmonary vein
  2. Pulmonary artery
  3. Superior vena cava
  4. Aorta Correct answer.

Explanation

Dextro-transposition of the great arteries is defined by ventriculoarterial discordance: the right ventricle gives rise to the aorta and the left ventricle gives rise to the pulmonary artery. Survival depends on mixing between the two parallel circulations.

Question 6Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which physical finding is most characteristic of coarctation of the aorta?

  1. Diminished femoral pulses Correct answer.
  2. Bounding femoral pulses
  3. Apical mid-diastolic murmur
  4. Continuous machinery murmur

Explanation

Coarctation narrows the aortic isthmus and produces upper extremity hypertension with weak, delayed femoral pulses. A radial-to-femoral pulse delay is a classic bedside clue.

Question 7Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A 3-month-old with a large perimembranous ventricular septal defect has a loud holosystolic murmur. Where is it best heard?

  1. Upper right sternal border
  2. Left lower sternal border Correct answer.
  3. Cardiac apex
  4. Infraclavicular area

Explanation

The murmur of a ventricular septal defect is holosystolic and is best heard at the left lower sternal border. Large defects may become quieter as ventricular pressures equalize and shunt velocity falls.

Question 8Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A 10-year-old with a large unrepaired ventricular septal defect presents with cyanosis and clubbing. Echocardiography shows right-to-left shunting. Which process explains this change?

  1. Development of infundibular stenosis
  2. Spontaneous closure of the defect
  3. Left ventricular failure
  4. Pulmonary vascular disease Correct answer.

Explanation

A long-standing large left-to-right shunt can cause pulmonary vascular obstructive disease and elevated pulmonary vascular resistance. When pulmonary pressure exceeds systemic pressure, the shunt reverses and cyanosis develops, known as Eisenmenger syndrome.

Question 9Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which auscultatory finding is typical of an uncomplicated secundum atrial septal defect?

  1. Fixed split of S2 Correct answer.
  2. Paradoxical split of S2
  3. Single second heart sound
  4. Narrow split of S2

Explanation

Right ventricular volume overload prolongs right ventricular ejection and delays pulmonary valve closure, producing a widely split S2 that does not vary with respiration. This fixed splitting is a hallmark of atrial septal defect.

Question 10Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A full-term infant has a continuous machinery murmur below the left clavicle and bounding pulses. Which lesion is most likely?

  1. Ventricular septal defect
  2. Coarctation of the aorta
  3. Patent ductus arteriosus Correct answer.
  4. Atrial septal defect

Explanation

A patent ductus arteriosus produces continuous flow from the higher-pressure aorta into the lower-pressure pulmonary artery, creating a machinery murmur. The diastolic runoff leads to bounding pulses and a wide pulse pressure.

Question 11Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A toddler with tetralogy of Fallot becomes acutely cyanotic and distressed. Which immediate measure is most appropriate?

  1. Epinephrine infusion
  2. Sodium nitroprusside infusion
  3. Isoproterenol infusion
  4. Knee-chest position Correct answer.

Explanation

Knee-chest positioning increases systemic vascular resistance and reduces the right-to-left shunt during a hypercyanotic spell. Oxygen, morphine, intravenous fluids, and beta-blockade are additional measures, while agents that increase contractility can worsen obstruction.

Question 12Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A neonate with dextro-transposition of the great arteries and a restrictive atrial septum remains cyanotic despite prostaglandin therapy. Which intervention improves mixing?

  1. Balloon atrial septostomy Correct answer.
  2. Beta-blocker administration
  3. Furosemide administration
  4. Indomethacin administration

Explanation

Balloon atrial septostomy enlarges the atrial communication and allows oxygenated and deoxygenated blood to mix in dextro-transposition. Prostaglandin maintains ductal patency but may not provide adequate mixing when the atrial septum is restrictive.

Question 13Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Truncus arteriosus is characterized by which anatomic finding?

  1. A restrictive atrial septum
  2. An absent pulmonary valve
  3. A single arterial trunk Correct answer.
  4. Two separate great arteries

Explanation

In truncus arteriosus, a single arterial trunk arises from the heart and supplies the systemic, pulmonary, and coronary circulations. A ventricular septal defect is almost always present, and the condition is associated with DiGeorge syndrome.

Question 14Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which form of total anomalous pulmonary venous return typically causes severe cyanosis and pulmonary edema in the first days of life?

  1. Mixed type
  2. Unobstructed supracardiac type
  3. Obstructed infracardiac type Correct answer.
  4. Unobstructed cardiac type

Explanation

Infracardiac total anomalous pulmonary venous return often drains through the portal venous system, where the pathway is narrow and obstruction is common. Obstruction causes pulmonary venous hypertension, pulmonary edema, and severe cyanosis shortly after birth.

Question 15Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which echocardiographic finding is characteristic of Ebstein anomaly?

  1. Anterior displacement of the tricuspid valve
  2. Superior displacement of the mitral valve
  3. Apical displacement of the tricuspid valve Correct answer.
  4. Lateral displacement of the pulmonary valve

Explanation

Ebstein anomaly involves apical displacement of the septal and posterior tricuspid leaflets, creating an atrialized portion of the right ventricle. The right atrium becomes enlarged, and accessory pathways such as Wolff-Parkinson-White syndrome are common.

Question 16Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A newborn with hypoplastic left heart syndrome is stable on prostaglandin E1. Which management step is most appropriate while awaiting staged surgery?

  1. High inspired oxygen concentration
  2. Immediate surgical ligation of the ductus
  3. Ductal patency with balanced flow Correct answer.
  4. Aggressive intravenous diuresis

Explanation

Systemic perfusion in hypoplastic left heart syndrome depends on a patent ductus arteriosus, so prostaglandin E1 is continued. Oxygen and ventilation are adjusted to avoid excessive pulmonary blood flow and maintain a balance between pulmonary and systemic circulation.

Question 17Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A child with an atrial septal defect undergoes catheterization. Saturations are superior vena cava 70%, pulmonary vein 98%, pulmonary artery 80%, and systemic artery 98%. Using the Fick principle, what is the pulmonary-to-systemic flow ratio?

  1. 1.6 Correct answer.
  2. 1.0
  3. 2.0
  4. 1.3

Explanation

The flow ratio is calculated as Qp/Qs = (systemic arterial saturation - mixed venous saturation) / (pulmonary venous saturation - pulmonary arterial saturation). Substituting the values gives (98 - 70) / (98 - 80) = 28/18, which is approximately 1.6.

Question 18Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

Which finding is the strongest contraindication to Fontan completion in a child with single-ventricle physiology?

  1. PVR of 8 Wood units/m2 Correct answer.
  2. Normal ventricular systolic function
  3. Mean pulmonary artery pressure of 12 mm Hg
  4. Unobstructed pulmonary veins

Explanation

Fontan circulation requires low pulmonary vascular resistance so blood can pass passively through the lungs. A pulmonary vascular resistance of 8 Wood units/m2 is markedly elevated and would cause low cardiac output after Fontan completion.

Question 19Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

In congenitally corrected transposition of the great arteries, which statement about the circulation is correct?

  1. The morphologic LV supports the lungs Correct answer.
  2. Systemic venous blood reaches the lungs through the morphologic RV
  3. The aorta arises from the morphologic LV
  4. Pulmonary venous blood reaches the aorta directly

Explanation

Congenitally corrected transposition combines atrioventricular and ventriculoarterial discordance. Systemic venous blood enters the morphologic left ventricle and is ejected to the lungs, while pulmonary venous blood enters the morphologic right ventricle and is ejected to the aorta.

Question 20Congenital Heart Disease (anatomy, pathophysiology, natural history, and surgical/interventional management)

A neonate with critical aortic stenosis presents in shock as the ductus arteriosus closes. Which initial therapy is most appropriate?

  1. High-dose diuretic therapy alone
  2. Indomethacin administration
  3. Prostaglandin E1 infusion Correct answer.
  4. Propranolol administration

Explanation

Critical aortic stenosis is duct-dependent in the neonate because systemic output may rely on flow through the ductus arteriosus. Prostaglandin E1 maintains ductal patency, and balloon aortic valvuloplasty is then performed to relieve obstruction.

Question 21Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

According to the classic case definition of Kawasaki disease, what is the minimum duration of fever required, in the absence of another explanation?

  1. At least 7 days
  2. At least 10 days
  3. At least 3 days
  4. At least 5 days Correct answer.

Explanation

Classic Kawasaki disease requires fever for at least 5 days together with at least four of the five principal clinical features. When fewer features are present but echocardiography shows coronary abnormalities, the illness is classified as incomplete Kawasaki disease rather than excluded. Shorter fever durations are accepted only in that incomplete scenario.

Question 22Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which ocular finding is one of the principal clinical features of Kawasaki disease?

  1. Bilateral non-exudative bulbar conjunctival injection Correct answer.
  2. Periorbital cellulitis with preseptal erythema
  3. Cataract with lens opacity
  4. Unilateral purulent conjunctivitis with eyelid swelling

Explanation

Kawasaki disease characteristically produces bilateral, non-exudative bulbar conjunctival injection that spares the limbus. Purulent discharge or unilateral involvement points instead toward an infectious conjunctivitis. The eye changes are one of the five principal features used in the case definition.

Question 23Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which regimen is first-line therapy during the acute febrile phase of Kawasaki disease?

  1. Intravenous immunoglobulin plus high-dose aspirin Correct answer.
  2. High-dose oral corticosteroids alone
  3. Subcutaneous low-molecular-weight heparin
  4. Oral amoxicillin-clavulanate for 10 days

Explanation

Prompt intravenous immunoglobulin at 2 g/kg together with high-dose aspirin reduces the frequency of coronary artery abnormalities and is the standard acute therapy. Treatment should begin within the first 10 days of illness, ideally as soon as the diagnosis is made. Antibiotics and anticoagulation alone have no role in the acute inflammatory phase.

Question 24Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which viral pathogen is classically associated with acute myocarditis in children?

  1. Rotavirus
  2. Respiratory syncytial virus
  3. Epstein-Barr virus
  4. Coxsackievirus B Correct answer.

Explanation

Enteroviruses, particularly coxsackievirus B, are the classic causes of viral myocarditis, although adenovirus, parvovirus B19, and other agents are also identified. The virus injures myocytes directly and triggers an immune-mediated inflammatory response. Many cases remain idiopathic despite extensive testing.

Question 25Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which of the following is a major Jones criterion for acute rheumatic fever?

  1. Fever
  2. Carditis Correct answer.
  3. Elevated erythrocyte sedimentation rate
  4. Prolonged PR interval on electrocardiography

Explanation

The major Jones manifestations are carditis, polyarthritis, chorea, erythema marginatum, and subcutaneous nodules. Fever, raised acute-phase reactants, arthralgia, and a prolonged PR interval are minor manifestations that support the diagnosis. Diagnosis requires evidence of preceding group A streptococcal infection plus either two major or one major and two minor criteria.

Question 26Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which electrocardiographic finding is most characteristic of acute pericarditis in a child?

  1. ST elevation confined to leads II, III, and aVF with reciprocal depression in aVL
  2. Diffuse concave ST-segment elevation with PR-segment depression Correct answer.
  3. Sawtooth atrial flutter waves at 300 beats per minute
  4. Short PR interval with a delta wave

Explanation

Acute pericarditis produces diffuse concave ST elevation across many leads with PR-segment depression, reflecting inflammation of the entire pericardium and underlying atrial epicardium. Territory-limited ST elevation with reciprocal change suggests myocardial infarction or regional myocarditis. Serial tracings evolve through stages over days to weeks.

Question 27Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

By echocardiography, a coronary artery internal diameter of which size defines a giant aneurysm in Kawasaki disease?

  1. 15 mm or greater
  2. 2.5 mm or greater
  3. 8 mm or greater Correct answer.
  4. 4 mm or greater

Explanation

Coronary aneurysms in Kawasaki disease are graded as small (under 5 mm), medium (5 to 8 mm), and giant (8 mm or greater, or a z-score of 10 or more). Giant aneurysms carry the highest risk of thrombosis and myocardial infarction and often require anticoagulation. Absolute diameters are interpreted alongside body-surface-area-adjusted z-scores.

Question 28Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

After a child with Kawasaki disease has defervesced and is clinically stable, what aspirin dose is recommended during the convalescent phase?

  1. 3 to 5 mg/kg/day as a single dose Correct answer.
  2. 80 to 100 mg/kg/day divided every 6 hours
  3. 30 mg/kg/day divided every 8 hours
  4. 10 mg/kg/day as a single dose

Explanation

High-dose anti-inflammatory aspirin is used during the febrile phase, then reduced to low-dose antiplatelet therapy of 3 to 5 mg/kg/day once daily. This low dose is continued for roughly 6 to 8 weeks when coronary arteries are normal, and longer when aneurysms persist. Low-dose therapy limits the risk of Reye syndrome while preserving antiplatelet effect.

Question 29Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

A 5-year-old with acute myocarditis has hypotension, cool extremities, and an ejection fraction of 25%. Which initial management approach is most appropriate?

  1. Inotropic support with afterload reduction, with early mechanical circulatory support planning Correct answer.
  2. Intravenous beta-blocker therapy to reduce myocardial oxygen demand and arrhythmia risk
  3. Rapid 20 mL/kg normal saline boluses repeated until blood pressure normalizes
  4. High-dose ibuprofen to treat myocardial inflammation

Explanation

The child is in cardiogenic shock from pump failure, so therapy aims to improve contractility and reduce afterload while avoiding volume loading of a failing ventricle. Milrinone and other inotropes are typical, and extracorporeal or ventricular assist support should be anticipated early if shock persists. Fluid resuscitation and negative inotropes can precipitate deterioration.

Question 30Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which investigation best demonstrates myocardial inflammation and fibrosis in a hemodynamically stable child with suspected myocarditis?

  1. Invasive coronary angiography with intravascular ultrasound of the left main coronary artery
  2. Exercise stress electrocardiography with continuous rhythm monitoring
  3. Chest radiograph with cardiothoracic ratio measurement
  4. Cardiac magnetic resonance imaging with late gadolinium enhancement Correct answer.

Explanation

Cardiac magnetic resonance imaging with tissue characterization, including late gadolinium enhancement and T1/T2 mapping, detects edema, hyperemia, and fibrosis consistent with myocarditis. It also helps exclude alternative diagnoses such as anomalous coronary arteries or infarction. The findings are interpreted using standardized criteria for myocardial inflammation.

Question 31Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which regimen is recommended to eradicate group A streptococcal pharyngitis and prevent a first attack of acute rheumatic fever?

  1. A single oral dose of amoxicillin
  2. Intravenous ceftriaxone once daily for 5 days
  3. A 3-day course of oral azithromycin
  4. Intramuscular benzathine penicillin G, single dose Correct answer.

Explanation

A single intramuscular dose of benzathine penicillin G reliably eradicates group A streptococci from the pharynx, and a 10-day oral penicillin or amoxicillin course is an acceptable alternative. Penicillin remains the drug of choice because group A streptococci have never developed resistance to it. Treatment must begin promptly to reduce the risk of subsequent rheumatic fever.

Question 32Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

A 12-year-old has acute idiopathic pericarditis with fever and pleuritic chest pain but normal blood pressure. Which combination is appropriate first-line anti-inflammatory therapy?

  1. Corticosteroids as monotherapy to avoid NSAID side effects
  2. Colchicine alone
  3. Aspirin plus prophylactic antibiotics
  4. An NSAID plus colchicine Correct answer.

Explanation

High-dose NSAID therapy combined with colchicine promptly relieves symptoms and reduces the risk of recurrence in acute pericarditis. Colchicine is continued for several months after the acute episode. Corticosteroids are generally avoided as first-line treatment because they increase recurrence risk and are reserved for specific indications.

Question 33Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

A child with Kawasaki disease remains febrile 48 hours after completing a standard infusion of intravenous immunoglobulin. What is the most appropriate next step?

  1. Low-dose aspirin alone with outpatient observation
  2. A second dose of intravenous immunoglobulin Correct answer.
  3. Warfarin anticoagulation with a target INR of 2.5
  4. Live attenuated MMR vaccination before discharge

Explanation

Persistent or recurrent fever after the initial immunoglobulin infusion indicates resistance, and a second dose of intravenous immunoglobulin at 2 g/kg is the usual next step. Children who remain refractory may receive corticosteroids, infliximab, or other adjunctive therapy. Ongoing fever also warrants repeat echocardiography to reassess the coronary arteries.

Question 34Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which valve lesion is most commonly found in chronic rheumatic heart disease in children?

  1. Aortic stenosis
  2. Tricuspid stenosis
  3. Mitral regurgitation Correct answer.
  4. Pulmonary stenosis

Explanation

The mitral valve is involved in the large majority of rheumatic heart disease, and pure or mixed mitral regurgitation is the typical childhood lesion. Mitral stenosis results from progressive leaflet scarring and usually becomes clinically evident years or decades later. Aortic valve involvement is the next most common, often accompanying mitral disease.

Question 35Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

A 14-year-old presents with syncope, a new complete atrioventricular block, and findings of mild myocarditis. Which infectious cause should be particularly considered?

  1. Coxsackievirus A
  2. Parvovirus B19
  3. Adenovirus
  4. Borrelia burgdorferi (Lyme disease) Correct answer.

Explanation

Lyme carditis classically causes fluctuating atrioventricular block, which may progress to complete block and syncope. The conduction abnormality often resolves with appropriate antibiotic therapy, although temporary pacing may be required for hemodynamic instability. Other viral myocarditis causes can produce arrhythmias but do not show this distinctive predilection for the conduction system.

Question 36Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which finding most suggests cardiac tamponade in a child with a large pericardial effusion?

  1. Loud first heart sound with a fixed split second heart sound
  2. Pulsus paradoxus with echocardiographic right ventricular diastolic collapse Correct answer.
  3. Widened pulse pressure with bounding peripheral pulses
  4. Increased systolic pressure during inspiration

Explanation

Tamponade occurs when pericardial pressure impairs ventricular filling, producing pulsus paradoxus and diastolic collapse of the right-sided chambers on echocardiography. Cardiac output becomes critically dependent on heart rate and preload. Urgent pericardial drainage is indicated when hypotension or poor perfusion accompanies these findings.

Question 37Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which statement about Kawasaki disease in infants younger than 6 months is most accurate?

  1. Fever is typically absent, so the diagnosis rests on echocardiographic findings alone
  2. Incomplete presentations are common and coronary complications are more frequent than in older children Correct answer.
  3. The disease is usually milder, so the risk of coronary aneurysm is lower than at age 3 years
  4. Coronary involvement is rare because transplacental maternal antibodies are protective

Explanation

Young infants often fail to fulfill the classic criteria, so diagnosis is delayed while coronary artery damage progresses. For this reason the incomplete form is overrepresented in this age group and aneurysm rates are higher. Clinicians should lower the threshold for echocardiography and consider treatment when suspicion is high.

Question 38Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

A 9-year-old girl has Sydenham chorea and a raised antistreptolysin O titer but no fever, arthralgia, or murmur. Which conclusion is best supported?

  1. Rheumatic fever cannot be diagnosed because two major Jones criteria must always be fulfilled
  2. The findings indicate post-streptococcal reactive arthritis rather than rheumatic fever
  3. Chorea is a minor manifestation, so the Jones criteria are not satisfied here
  4. Chorea plus evidence of streptococcal infection is sufficient for diagnosis Correct answer.

Explanation

Chorea is a major manifestation and is recognized as an exception to the usual requirement for two major or one major plus two minor criteria when streptococcal infection has been documented. Sydenham chorea may appear months after the inciting pharyngitis, when throat cultures are negative and only serology is positive. Echocardiography is still needed because carditis may be clinically silent.

Question 39Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which combination of findings most favors acute myocarditis rather than idiopathic dilated cardiomyopathy in a child with new severe left ventricular dysfunction?

  1. Persistently normal C-reactive protein and troponin levels with an indolent course
  2. Severe left ventricular dilatation with endocardial fibroelastosis on biopsy
  3. A 2-year history of slowly progressive exercise intolerance with a family history of cardiomyopathy
  4. A recent viral prodrome with elevated troponin and heart failure over days Correct answer.

Explanation

A brief viral prodrome followed by rapidly progressive ventricular dysfunction with raised troponin supports an inflammatory myocardial process. Idiopathic dilated cardiomyopathy typically evolves insidiously without acute-phase markers. The distinction matters because some myocarditis patients recover ventricular function with supportive care.

Question 40Acquired and Inflammatory Heart Disease (Kawasaki disease, myocarditis, rheumatic disease, pericardial disease)

Which catheterization finding is most characteristic of constrictive pericarditis?

  1. A step-up in oxygen saturation at the atrial level
  2. Equal right atrial and pulmonary capillary wedge pressures with a large effusion
  3. A large right ventricular end-diastolic volume with restrictive filling
  4. Discordant respirophasic ventricular systolic pressures with prominent right atrial y descents Correct answer.

Explanation

A rigid pericardium couples the ventricles, so inspiration raises right-sided and lowers left-sided pressures, producing discordant respirophasic changes. The rapid early diastolic filling that follows is cut short, giving a steep y descent and the classic square-root pressure waveform. These features distinguish constriction from restriction, in which ventricular interdependence is absent.

Question 41Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

Using Bazett correction, what is the upper limit of a normal QTc interval in a child?

  1. 400 ms
  2. 480 ms
  3. 420 ms
  4. 440 ms Correct answer.

Explanation

In children, a QTc of 440 ms or less by Bazett is generally considered normal. Values above 460 ms, especially with symptoms or a family history of sudden death, raise concern for long QT syndrome and warrant further evaluation.

Question 42Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

What is the most common mechanism of supraventricular tachycardia in infants?

  1. Automatic atrial tachycardia
  2. Atrial flutter
  3. Accessory-pathway AV reentry Correct answer.
  4. AV nodal reentry

Explanation

Most SVT in infants is orthodromic AV reentrant tachycardia using a concealed or manifest accessory pathway. AV nodal reentry is uncommon before adolescence, and atrial flutter or automatic atrial tachycardia are far less frequent.

Question 43Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

Which ECG pattern is characteristic of ventricular preexcitation (Wolff-Parkinson-White syndrome)?

  1. Normal PR interval together with an epsilon wave
  2. Short PR, wide QRS, delta wave Correct answer.
  3. Prolonged PR interval together with a narrow QRS complex
  4. Prolonged QT interval together with T-wave alternans

Explanation

Ventricular preexcitation produces a short PR interval, a slurred upstroke (delta wave), and a wide QRS because the ventricle is activated early through the accessory pathway. The delta wave may be subtle when the pathway conducts only intermittently.

Question 44Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

Congenital complete heart block in a newborn is most strongly associated with which maternal antibody?

  1. Anti-dsDNA antibody
  2. Anti-Smith antibody
  3. Anti-Ro/SSA antibody Correct answer.
  4. Anti-thyroid peroxidase antibody

Explanation

Maternal IgG anti-Ro/SSA (and anti-La/SSB) antibodies cross the placenta and can injure the fetal AV node, producing congenital complete heart block. Anti-dsDNA and anti-Smith are associated with lupus but not with this neonatal complication.

Question 45Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

Which description best fits sinus arrhythmia in a healthy child?

  1. Abrupt onset and termination without warning
  2. Respiratory phasic variation with sinus P waves Correct answer.
  3. Irregular rhythm with absent P waves
  4. Fixed PP interval with dropped beats

Explanation

Sinus arrhythmia is a normal respiratory variation in sinus rate, with each P wave followed by a QRS and no abrupt termination. It is common in healthy children and requires no treatment.

Question 46Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

What is the standard initial intravenous dose of adenosine for pediatric SVT?

  1. 0.01 mg/kg
  2. 0.1 mg/kg Correct answer.
  3. 0.5 mg/kg
  4. 0.05 mg/kg

Explanation

The standard first dose of adenosine for pediatric SVT is 0.1 mg/kg rapid IV push, with a maximum initial dose of 6 mg. If there is no response, 0.2 mg/kg (maximum 12 mg) may be given.

Question 47Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

Which drug should be avoided in a child with pre-excited atrial fibrillation?

  1. Adenosine Correct answer.
  2. Synchronized cardioversion
  3. Procainamide
  4. Ibutilide

Explanation

In pre-excited atrial fibrillation, AV nodal blocking drugs such as adenosine, verapamil, diltiazem, digoxin, and beta-blockers can increase conduction over the accessory pathway and precipitate ventricular fibrillation. Procainamide, ibutilide, or synchronized cardioversion are preferred.

Question 48Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

Which finding is most consistent with catecholaminergic polymorphic ventricular tachycardia (CPVT)?

  1. Short PR with a delta wave on baseline ECG
  2. Prolonged QT at rest with T-wave alternans
  3. Fixed first-degree AV block at rest
  4. Normal resting ECG with exercise-induced bidirectional VT Correct answer.

Explanation

CPVT is caused by abnormal ryanodine receptor calcium handling; the resting ECG is typically normal, and exercise or emotion provokes bidirectional or polymorphic VT. Beta-blockers are first-line, with flecainide added when needed.

Question 49Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

Which medication is first-line therapy for long QT syndrome in children?

  1. Nadolol Correct answer.
  2. Flecainide
  3. Digoxin
  4. Verapamil

Explanation

Beta-blockers, particularly nadolol or propranolol, are first-line therapy for long QT syndrome and reduce the risk of torsades de pointes and sudden death. Verapamil, digoxin, and flecainide do not shorten the QT interval and may be harmful.

Question 50Arrhythmias and Electrophysiology (diagnosis, antiarrhythmic therapy, ablation, device therapy)

What is the most appropriate initial management of junctional ectopic tachycardia after congenital heart surgery?

  1. Synchronized cardioversion
  2. Adenosine
  3. Verapamil
  4. Cooling, sedation, and amiodarone Correct answer.

Explanation

JET after congenital heart surgery is an automatic tachycardia, so cardioversion and adenosine are ineffective. Management focuses on correcting electrolytes, sedation, active cooling, atrial pacing, and amiodarone when needed.