Lets Scratch Our Brain for the Tender Hearts: Pediatric Cardiology Quiz

1. You are seeing a 15-year-old boy in the clinic who has hypertrophic cardiomyopathy. On examination, he has a crescendo–decrescendo systolic murmur along the left sternal border. Which of the following provocative maneuvers would decrease the intensity of the murmur?

2. A series of studies are undertaken to differentiate between restrictive cardiomyopathy and constrictive pericarditis in a 12-year-old boy. Which of the following findings would be more consistent with restrictive cardiomyopathy?

3. Which of the following is least associated with significant branch pulmonary artery stenoses?

4. Intravenous contrast injection may cause which of the following?

5. Which of the following statements is correct concerning contrast echocardiography?

6. A 9-year-old young boy, after being evaluated by an ophthalmologist for drooping eyelids, is noted to have a first-degree atrioventricular (AV) block, a right bundle branch block, and a left anterior vesicular block on a 12-lead electrocardiogram. What would be the most logical next step?

7. A 12-year-old patient with dilated cardiomyopathy is on digoxin, furosemide, and enalapril for his heart failure. He is now starting to have frequent episodes of supraventricular tachycardia (SVT), and you would like to start him on amiodarone. What medications do you have to adjust?

8. What is the most commonly accepted method of indexing maximum oxygen uptake (VO₂max) in clinical exercise testing?

9. Which method of exercise would achieve a higher maximum oxygen uptake?

10. Which cardiac exercise parameter has a limited increase with exercise in the supine position early in exercise?

11. Which of the following is a supplemental lab finding used in the diagnosis of Kawasaki disease?

12. What is the most common clinical finding in a 7-year-old patient with an anomalous right coronary artery from the left sinus?

13. A 6-year-old male is referred to pediatric cardiology secondary to a low-density lipoprotein (LDL) concentration of 170 mg/dL. Pertinent family history includes a grandfather with coronary vascular disease and a first myocardial infarction at age 50. The patient has a body mass index (BMI) that puts him in the 90th percentile. Which of the following is the best management step?

14. A 5-month-old child with single ventricle anatomy returns after a bidirectional cavopulmonary anastomosis. The saturation is 72%, and the pressure in the superior vena cava is 22 mm Hg, while the left atrial pressure is 4 mm Hg. Which of the following conditions is the most likely explanation for this hemodynamic profile?

15. Of the following pediatric patients, which would be the least likely to have an elevated right atrial pressure of 14 mm Hg?

ANSWERS

1. D. The murmur described is that of dynamic outflow tract obstruction. This murmur is typically increased by anything that increases the gradient. Thus, it will be louder with exercise, standing (particularly after squatting), and with the straining portion of the Valsalva maneuver. Systemic vasodilation with nitroglycerine or administration of isoproterenol will also increase the gradient. Stimulation of the α-adrenergic system will increase the afterload pressure, decreasing the gradient and thus the intensity of the dynamic outflow murmur.

2. B. In restrictive cardiomyopathy, the RVSP is often >50 mm Hg, as opposed to constrictive pericarditis, where it is typically <50 mm Hg. The other options, including the presence of a septal bounce, normal atrial size, equal RVEDP and LVEDP, and normal pulmonary vascular resistance index, are more typical of constriction. Patients with restrictive cardiomyopathy will have significantly enlarged atria and will rarely show changes in Doppler flow velocities with inspiration and expiration.

3. A. Typical syndromes in which the patient may have peripheral pulmonary branch stenosis include Congenital Rubella, Williams, and Alagille. Edward syndrome (trisomy 18) is typically associated with ventricular septal defect (VSD) and valve abnormalities (polyvalvular).

4. B. When contrast material reaches the coronary circulation, there is coronary vasodilation and chelation of calcium from the blood and probably the intracellular fluid. There is a drop in coronary hematocrit due to an increase in intravascular water from the tissues, which results in decreased myocardial contractility.

5. C. Contrast agents are designed to pass through the pulmonary capillary bed to opacify the left heart structures. The typical size of these microspheres is 1–10 µm. The acoustic impedance of contrast agents is much lower than that of the blood pool. The contrast effect persists for 3–5 min with most contrast agents.

6. A. The Kearns–Sayre syndrome (characterized by its onset before the age of 20 years, chronic ophthalmoplegia, pigmentary retinal degeneration, and at least one of the following symptoms: ataxia, heart block, and high protein content in the cerebrospinal fluid) is a severe variant of chronic progressive external ophthalmoplegia with frequent rearrangements of the mitochondrial deoxyribonucleic acid (DNA). Patients typically present with a bundle branch block and a prolonged QT interval that progresses to complete heart block. Prophylactic pacemaker therapy is advisable in patients suffering from the Kearns–Sayre syndrome who have bifascicular block on the precordial electrocardiogram, as they may rapidly progress to complete AV block. Although they are at risk for AV block, there is no indication for a prophylactic ICD. Steroids or an electrophysiology study is of no benefit.

7. A. Amiodarone increases warfarin effect, digoxin and phenytoin levels, and class I antiarrhythmic toxicity. Digoxin is excreted primarily by the kidneys. Digoxin dose should be reduced when given in conjunction with amiodarone. There is no significant interaction between angiotensin-converting enzyme (ACE) inhibitors or furosemide and amiodarone.

8. D. Maximum oxygen uptake is closely related to cardiac output. The more work/exercise a patient does, the more oxygen uptake will be needed. This increased oxygen demand is supplied by increasing the uptake for the increased muscle groups being used. Many methods for indexing VO₂max have been suggested, but a constant is hard to accomplish. Males tend to have a higher lean body mass than females, which causes differences in VO₂max between the sexes. VO₂max also changes with increasing age. Previous studies have revealed that an exponent of body length (1.5–3.21) has also been unreliable. The most commonly accepted method of indexing VO₂max is body weight. It has been shown to possess a relatively constant method of indexing in older childhood/early-adolescent males and females and seems to be the method with the least limitations.

9. D. The maximum VO₂max that can be achieved depends on the type of work performed. The more muscle mass is used, the more oxygen supplementation is required for those muscle groups to continue to perform. Therefore, the VO₂max would be considerably higher for the treadmill exercise test (running = the use of many different/whole-body muscle groups) versus the other types of exercise testing listed that only use select muscle groups.

10. C. Stroke volume is dependent on left ventricular end-diastolic volume and ejection fraction. In the supine position, stroke volume increases normally due to increased volume return (increased end-diastolic volume) to the heart. Thus, the stroke volume is already increased from baseline, and the volume needed to reach maximum stroke volume is small and limited. Finally, stroke volume primarily increases early in exercise and increases little thereafter. Bodily position will not limit the increase of the other parameters listed to the same extent as stroke volume.

11. E. The supplemental laboratory criteria used in the diagnosis of suspected incomplete Kawasaki disease include albumin ≤3.0 g/dL, anemia for age, elevation of alanine aminotransferase, platelets after 7 days ≥450,000/mm³, white blood cell count ≥15,000/mm³, and urine ≥10 white blood cells/high-power field.

12. C. If an anomalous coronary arises from the opposite sinus of Valsalva, it is very unlikely to pass between the aorta and the right ventricular infundibulum, which is when it is at most risk for myocardial ischemia. Therefore, most people with this anomaly are completely asymptomatic. There is, however, a risk of sudden death with this anomaly, although the exact incidence is unknown. Basso et al. reported 27 deaths in young athletes whose autopsies showed anomalous origin of a coronary artery from the wrong sinus. Fifteen athletes had no prior cardiovascular symptoms. Of the remaining 12 patients, 10 had symptoms, including 4 with syncope, 5 with chest pain, 2 with palpitations, and 1 with dizziness.

13. E. Cholesterol screening should be performed on all children with a positive family history of dyslipidemia or premature coronary vascular disease or dyslipidemia. Screening should also be performed on all children with unknown family history or the following risk factors: overweight or obese, hypertension, cigarette smoking, or diabetes mellitus. This child was appropriately screened given his positive family history of premature coronary vascular disease. Pharmacotherapy should not be started until the child is 8 years of age. At this age, weight management should be the focus to lower the LDL level.

14. D. Any distortion of the pulmonary artery (in situ thrombus, stenosis, external compression, etc.) would impede pulmonary blood flow and result in an elevated SVC pressure. This elevation in SVC pressure could result in the opening of vestigial veins that would then drain venous blood into the heart, thus leading to systemic desaturation. In this case, there was insufficient decompression of these veins as the SVC pressure was still very elevated. Other conditions that would result in a similar hemodynamic profile (increased SVC pressure but without a concomitant increase in left atrial pressure) would be etiologic factors such as elevated pulmonary vascular resistance, pleural effusion, atelectasis, hyperinflation, and pulmonary vein stenosis. The other conditions listed in the answer section would result in not just an elevated SVC pressure but also an elevated left atrial pressure.

15. C. Restrictive cardiomyopathy patients have characteristically elevated right and left atrial pressures and pulmonary hypertension. A child with a large pericardial effusion will have elevated right atrial pressures. A child with tetralogy of Fallot will have right ventricular hypertrophy and a stiff right ventricle, and this is exacerbated by any residual RVOT obstruction. Finally, a child with chronic dilated cardiomyopathy will have elevated right and left atrial pressures. An infant with moderate tricuspid valve regurgitation, due to a relatively compliant right atrium, can have regurgitation and an enlarged right atrium but without significantly elevated right atrial pressure.