Intracardiac Shunts
Matthew D. Read
1. You are performing an echocardiogram on a 31-year-old woman who had a syncopal episode while playing basketball. She reports several instances of having to sit down prior to feeling like she would faint. Given the finding shown in Figure 37.1, which of the following is most likely true?
 Figure 37.1 |
A. The patient has significant mitral regurgitation from a cleft leaflet.
B. The patient has a defect in the septum primum.
C. The patient has cyanosis during her presyncopal and syncopal episodes.
D. The finding shown is associated with an inlet ventricular septal defect (VSD).
View Answer
1. Correct Answer: B. It is a defect in the septum primum.
Rationale: Figure 37.1 shows a secundum ASD, which is a defect arising from increased apoptosis of the septum primum. While the patient may have significant mitral regurgitation, it would most likely be due to mitral valve prolapse (MVP) in the setting of a secundum ASD. A cleft mitral valve is associated with a septum primum. The patient has a left-to-right shunt as demonstrated on color Doppler imaging, thus is unlikely to have cyanosis as part of her episodes. A secundum ASD is not associated with an inlet VSD. An inlet VSD is associated with a primum ASD. Figure 37.9 depicts the different types of ASDs.
 Figure 37.9 A, A schematic of the relationship of different types of atrial septal defects (ASDs) viewed from the perspective of the right heart. B, The differences of different types of ASDs from a subcostal four-chamber perspective. IVS, interventricular septum; LA, left atrium; RA, right atrium; RUPV, right upper pulmonary vein. |
Selected References
1. Armstrong WF, Ryan T. Congenital heart diseases. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:544-610;Chapter 19.
2. Brickner ME. Congenital heart disease. In: Topol EJ, ed. Textbook of Cardiovascular Medicine. 3rd ed. Lippincott Williams and Wilkins; 2007:502-536;Chapter 30.
2. Which image in Figure 37.2 is most likely to be found in a patient with an atrioventricular (AV) canal defect?
 Figure 37.2 |
A. Figure 37.2A
B. Figure 37.2B
C. Figure 37.2C
D. Figure 37.2D
View Answer
2. Correct Answer: B. Figure 37.2B
Rationale: Figure 37.2B, Choice B shows an apical four-chamber view with an ASD as well as the tricuspid and mitral valves in the same plane, a defining feature of an AV canal defect. Figure 37.2A, Choice A shows a dilated coronary sinus, in a posteriorly directed apical four-chamber view, in a patient with a persistent left superior vena cava (SVC). A persistent left SVC by itself is not a shunt; however, it may be associated with an unroofed coronary sinus or an anomalous pulmonary venous return. Figure 37.2C, Choice C shows a normal heart in the apical four-chamber view. Figure 37.2D, Choice D shows a muscular VSD, which is not a component of an AV canal.
Selected References
1. Armstrong WF, Ryan T. The comprehensive echocardiographic examination. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:61-99;Chapter 4.
2. Armstrong WF, Ryan T. Congenital heart disease. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:544-610;Chapter 19.
3. Silvestry FE, Cohen MS, Armsby LB, et al. Atrial septal defect and patent foramen ovale: from the American Society of Echocardiography and Society for Cardiac Angiography and Interventions. J Am Soc Echocardiogr. 2015;28(8):910-958.
4. Stout KK, Daniels CJ, Aboulhosn JA, et al. 2018 AHA/ACC guideline for the management of adults with congenital heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;139:e698-e800.
3. A 35-year-old man with dyspnea is undergoing echocardiographic evaluation for a systolic murmur concerning for mitral regurgitation. Which of the following intracardiac shunts is most likely associated with the finding shown in Figure 37.3?
 Figure 37.3 |
A. Membranous VSD
B. Ostium primum atrial septal defect (ASD)
C. Ostium secundum ASD
D. Inlet VSD
View Answer
3. Correct Answer: C. Ostium secundum ASD
Rationale/Critique: Figure 37.3 is an apical four-chamber view showing MVP, causing the patient’s mitral regurgitation. MVP is associated with the presence of an ostium secundum ASD. An ostium primum ASD is associated with an inlet VSD. An AV canal exists when an ostium primum ASD and inlet VSD coexist. An isolated VSD, a partial AV canal, and complete AV canal are all part of a spectrum of lesions, collectively known as endocardial cushion defects. An ostium primum ASD is also associated with a cleft AV valve and regurgitation, in addition to trisomy 21. A membranous VSD is associated with ventricular septal aneurysms, aortic insufficiency, and aortic valve cusp prolapse into the VSD.
Selected References
1. Armstrong WF, Ryan T. Congenital heart disease. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:544-610;Chapter 19.
2. Leachman R, Cokkinos D, Cooley D. Association of ostium secundum atrial septal defects with mitral valve prolapse. Am J Cardiol. 1976;38(2):167-169.
3. Smer A, Nanda NC, Akdogan RE, Elmarzouky ZM, Dulal S. Echocardiographic evaluation of mitral valve regurgitation. Mini-invasive Surg. 2020;4:52.
4. Stout KK, Daniels CJ, Aboulhosn JA, et al. 2018 AHA/ACC guideline for the management of adults with congenital heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;139:e698-e800.
4. A 43-year-old woman is undergoing echocardiography for evaluation of hemodynamic instability and dyspnea. She is found to have severe mitral regurgitation with a cleft valve. Based on Figure 37.4, which of the figure parts is most likely to be associated with a cleft mitral valve?
 Figure 37.4 |
A. Figure 37.4A
B. Figure 37.4B
C. Figure 37.4C
D. Figure 37.4D
View Answer
4. Correct Answer: A. Figure 37.4A
Rationale: Figure 37.4A shows an inlet VSD (aka AV canal type) that is associated with a cleft mitral valve. An inlet VSD is part of the spectrum of endocardial cushion defects. An isolated VSD, a partial AV canal, and complete AV canal are all endocardial cushion defects.
Figure 37.4.B shows a muscular VSD (aka trabeculated).
Figure 37.4C shows a membranous VSD (aka perimembranous, conoventricular), with the left image being a modified apical two chamber showing the aorta and LVOT and VSD with left-to-right shunt just above the aortic valve, while the right image shows the VSD in the membranous region, closer to the tricuspid valve (as opposed to an outlet VSD which is closer to the pulmonic valve). A membranous VSD is the most common VSD and is associated with ventricular septal aneurysms, aortic insufficiency, and aortic valve cusp prolapse into the VSD.
Figure 37.4D shows an outlet VSD (aka infundibular, supracristal, infracristal, subarterial, subpulmonary, conal, or doubly committed juxta-arterial), seen in parasternal long axis on the left and in parasternal short axis on the right, close to the pulmonic valve (as opposed to a membranous VSD which is closer to the tricuspid valve). An outlet VSD is associated with aortic insufficiency (more so than a membranous VSD). Figure 37.10 depicts the different types of VSDs.
 Figure 37.10 A, Schematic of the right ventricular surface of the interventricular septum (IVS) diagramming common locations of ventricular septal defects. Region 1, membranous IVS; region 2, outflow IVS; region 3, trabecular septum; region 4, inflow septum; region 5, supracristal region; region 6, distal multiple “Swiss cheese” septal defects. B-F, Schematic depicting the locations of the various types of ventricular septal defects, which is more relative to the transthoracic views obtained. AO, aorta; FO, fossa ovalis; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; MV, mitral valve; PA, pulmonary artery; PM, papillary muscle; PV, pulmonic valve; RA, right atrium; RAA, right atrial appendage; RV, right ventricle; RVOT, right ventricular outflow tract; SVC, superior vena cava; TV, tricuspid valve. |
Selected References
1. Armstrong WF, Ryan T. Congenital heart disease. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:544-610;Chapter 19.
2. Jacobs J, Mavroudis C. Congenital heart surgery nomenclature and database project: ventricular septal defect. Ann Thorac Surg. 2000;69(3):25-35.
3. Stout KK, Daniels CJ, Aboulhosn JA, et al. 2018 AHA/ACC guideline for the management of adults with congenital heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;139:e698-e800.
5. A 19-year-old woman is being evaluated for possible VSD closure. Her left ventricular outflow tract (LVOT) diameter is 2.2 cm and her right ventricular outflow tract (RVOT) diameter is 2.5 cm. The following information is also gathered: LVOT peak velocity = 92.8 cm/s, LVOT velocity time integral = 17.3 cm, RVOT peak velocity = 66.6 cm/s, and RVOT velocity time integral = 16.6 cm. What is the calculated shunt ratio?
A. 0.8
B. 0.9
C. 1.1
D. 1.2
View Answer
5. Correct Answer: D. 1.2
Rationale: The shunt ratio for this patient is 1.2. The shunt ratio (Qp/Qs) is calculated as in the equation below:
where
SV = πr2 × VTI
Qp = pulmonary blood flow, Qs = systemic blood flow, r= radius of outflow tract, SV = stroke volume, VTI = velocity time integral of blood flow through the outflow tract
Selected References
1. Armstrong WF, Ryan T. Congenital heart diseases. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:544-610;Chapter 19.
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