1. (A) KD guidelines of 2017 recommend repeating echocardiograms twice a week in patients with important or evolving coronary artery abnormalities (Z-score >2.5) noted during the acute phase of KD, until the coronary dimensions have stopped progressing. As the clinical features of inflammation have resolved with the 1st dose of IVIG, a repeat dose of IVIG or oral steroids is not needed.

2. (A) The mitral valve is the most commonly involved cardiac valve in systemic lupus erythematosus. The aortic valve is the 2nd most common, followed by the tricuspid valve and finally the pulmonary valve.

3. (B) The risk in the 1st child in mothers with positive SSA/SSB antibodies is 1% to 5%. If the 1st child has congenital complete heart block, the risk in 2nd child goes up to 11% to 19%. Complete heart block can manifest any time between 16 and 28 weeks of gestation; therefore, a normal fetal echocardiogram at 19 weeks of gestation does not alleviate the risk.

4. (D) The MR angiogram shows coarctation of the abdominal aorta. This image along with the clinical picture is consistent with the diagnosis of Takayasu arteritis.

5. (E) The clinical picture is consistent with Pompe disease, which is a lysosomal storage disease due to acid alphaglucosidase deficiency. Enzyme replacement therapy with alglucosidase alfa given intravenously every 2 weeks is the most effective treatment for cardiomyopathy and developmental delays.

6. (C) Magnetic resonance imaging with T2* quantification is the best test to quantitate iron load in myocardium and the liver. Echocardiography and tissue Doppler may show restrictive pattern in hemosiderosis. Cardiac catheterization, liver magnetic resonance elastography, and liver biopsy are not needed for this purpose.

7. (B) Large joint arthritis is a feature of late Lyme disease. All other options are features of early localized and early disseminated Lyme disease.

8. (A) The patient has acute rheumatic fever with carditis. The echocardiogram shows severe mitral valve regurgitation, which is the most common manifestation of acute rheumatic carditis. Left heart enlargement and a small amount of pericardial effusion along the right atrium and right ventricle can also be noted. The treatment includes (1) antibiotics against group A streptococcal infection, (2) anti-inflammatory therapy with NSAIDs or high-dose aspirin, and (3) treatment of congestive heart failure. Penicillin G benzathine is a long-acting intramuscular injection that serves as prevention of group A streptococcal infection. Naproxen has favorable side effect profile compared to high-dose aspirin and is a preferred choice as an anti-inflammatory agent. Furosemide is needed in this child as there is evidence of respiratory distress and pulmonary edema from mitral regurgitation. IVIG and high-dose aspirin are first-line treatment for Kawasaki disease. IVIG is typically not used in acute rheumatic fever unless there is severe Sydenham chorea which is not responding to other therapy.

9. (B) Mitral valve stenosis in isolation and in combination with aortic valve disease is the most common manifestation of chronic rheumatic heart disease.

10. (D) Amiodarone exposure can cause hypothyroidism which will cause low TSH and high free T4. An elevated TSH with normal free T4, indicative of subclinical hypothyroidism, can also be seen after amiodarone exposure.

11. (B) HIV disease can cause vasculitis of the aorta and pulmonary arteries that can lead to diffuse stenosis. Late syphilis causes occlusion of vasa vasorum of large vessels resulting in aneurysmal dilation, not stenosis, of aorta. Other options are not associated with large vessel vasculopathy.

12. (B) Thoracic radiation exposure can lead to a degenerative process of the mitral valve which typically starts from the annulus and progresses toward the leaflet tips. Anthracycline exposure is more commonly associated with cardiomyopathy. Infective and nonbacterial thrombotic endocarditis typically do not involve the valve annulus primarily.

13. (D) Nonbacterial thrombotic endocarditis in systemic lupus erythematosus is not infective and does not need antibiotic prophylaxis. However, these vegetations can embolize and are not completely inconsequential. Rarely, surgical resection is needed for large vegetations.