1. Correct Answer: B. Ostium secundum ASD

Rationale: ASDs are the most common acyanotic congenital heart defect occurring in 0.1% of births. They are the most common cause of clinically significant intracardiac shunts, accounting for 30% to 40% of cases. Echocardiographic evaluation of ASD includes detection and quantification of size and shape of septal defects, evaluation of rims of tissue surrounding the defect, the degree of shunting and remodeling, and changes in size and function of cardiac chambers. The direction of shunting should be assessed via color flow Doppler and the presence of associated congenital defects should be evaluated.

Ostium secundum defects are the most common form of true ASDs and are defects in the septum primum tissue. Secundum ASDs are the most amenable to percutaneous closure via transcatheter techniques. Ostium primum defects are within the spectrum of atrioventricular (AV) canal defects and are characterized by an atrial communication resulting from the absence of the AV canal portion of the atrial septum, near the AV valves. Sinus venosus defects are less common and are not true ASDs, resulting from partial or complete absence of the sinus venosus septum between the superior vena cava and right upper pulmonary vein or the inferior vena cava and the right lower or middle pulmonary veins. PFO is not a true defect of atrial tissue, but rather a separation between the septum primum and septum secundum that occurs in 25% of the adult population. (See Figure 33.10.)

1. Congenital heart disease. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:544-607.

2. Silvestry FE, Cohen MS, Armsby LB, et al. Guidelines for the echocardiographic assessment of 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;29:910-958.

2. Correct Answer: A. Right ventricular dilation

Rationale: The hemodynamic effects of ASDs are a result of the direction and magnitude of shunting between the right and left atrium. The direction and magnitude of shunting depend on the size of the defect as well as the relative compliances of the systemic vasculature, pulmonary vasculature, and the left and right ventricle. Initially, the pulmonary vasculature is able to accommodate for the increase in flow secondary to an ASD, leading to a left-to-right shunt without a substantial rise in pulmonary arterial pressure. However, over time, the continued increase in left-to-right shunt flow will lead to right ventricular dilation and then eventually pulmonary hypertension.

Right ventricular hypertrophy may result after prolonged increase in left-to-right shunt flow leading to pulmonary hypertension but would likely result after right ventricular dilation. LV dilation and LV hypertrophy would not be the expected initial echocardiographic finding in a patient with left-to-right shunting.

1. Silvestry FE, Cohen MS, Armsby LB, et al. Guidelines for the echocardiographic assessment of 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;29:910-958.

3. Correct Answer: C. Patients with cryptogenic stroke and a PFO should also be evaluated for the presence of deep venous thrombosis.

Rationale: Right-to-left shunting through a PFO may lead to paradoxical emboli and can present as a cryptogenic stroke. PFOs typically close within 3 months after birth but may persist through adulthood in 25% to 30% of the population. The diagnosis of PFO relies on ultrasonography, either by echocardiography or transcranial Doppler techniques. TEE has increased sensitivity for detection of PFO compared to TTE (Choice B is incorrect), but TTE is often the initial test of choice as it is noninvasive. Presence of a PFO after cryptogenic stroke should prompt an evaluation for the presence of deep venous thrombi (Choice C is correct). Antiplatelet therapy is the initial treatment of choice for patients with cryptogenic stroke who have a PFO. Percutaneous closure devices eliminate the PFO and may be considered as a means for secondary stroke prevention. However, multiple randomized trials did not demonstrate significantly reduced rates of recurrent ischemic stroke with closure compared to medical therapy alone (Choice A is incorrect). A retrospective analysis of patients with an incidentally discovered PFO at the time of surgery demonstrated a higher risk of perioperative stroke in patients who underwent surgical closure, although there was no long-term difference in outcomes (Choice D is incorrect).

1. Mas JL, Derumeaux G, Guillon B, et al. Patent foramen ovale closure or anticoagulation vs. antiplatelets after stroke. N Engl J Med. 2017;377:1011.

2. Mathew JP, Ayoub CM, Swaminathan M. Transesophageal echocardiography for congenital heart disease. In: Clinical Manual and Review of Transesophageal Echocardiography. 2nd ed. The McGraw-Hill Companies, Inc.; 2010:406-439;Chapter 18.

3. Saver JL. Cryptogenic stroke. N Engl J Med. 2016;374:2065-2074.

4. Correct Answer: A. Cleft mitral valve

Rationale: Ostium primum defects are one of the several variants of common AV canal defects and result in an interatrial communication near the AV valves. Ostium primum defects are usually associated with abnormalities of the AV valves, most commonly a cleft in the anterior mitral leaflet.

Ostium secundum defects, the most common form of ASDs, are true defects in the atrial septum in the region of the fossa ovalis. The most common associated anomaly with ostium secundum defects is mitral valve prolapse. Mitral valve prolapse is the superior displacement of one or both mitral valve leaflets into the left atrium (at least 2 mm) during systole. Marked displacement of the mitral leaflet may lead to MR.

The two less common forms of ASDs are sinus venosus defects and coronary sinus defects. Sinus venosus defects are a communication between one or more of the right pulmonary veins with either the superior vena cava (superior sinus venosus defect) or inferior vena cava (inferior sinus venosus defect). Sinus venosus defects represent 4% to 11% of all ASDs and are most commonly associated with anomalous pulmonary venous return.

Coronary sinus defects are the least common form of ASDs and result from partial or complete unroofing of tissue separating the coronary sinus from the left atrium. PLSVC is associated commonly with coronary sinus septal defects and when found together is termed Raghib syndrome.

1. Geva T, Martins JD, Wald RM. Atrial septal defects. Lancet. 2014;383:1921-1932.

5. Correct Answer: C. Bicuspid aortic valve

Rationale: The parasternal short-axis view at the level of the aortic valve demonstrates a bicuspid aortic valve.

Bicuspid aortic valves with superimposed calcific changes are a common cause of aortic stenosis. Bicuspid valves most often result from fusion of the right and left coronary cusps, as is suggested in Figure 33.2. Dilation of the aortic root and tubular ascending aorta is associated with bicuspid aortic valvular disease and may be visualized by echocardiography, but it is not suggested by Figure 33.2.

Parachute mitral valve is a congenital lesion characterized by unifocal attachment of the mitral chordae tendineae to a single papillary muscle, which may lead to mitral valve stenosis. Ebstein anomaly is a congenital anomaly of the tricuspid valve in which the tricuspid leaflets are tethered by varying degrees to the right ventricular free wall and ventricular septum leading to significant tricuspid regurgitation and a small right ventricular size.

The image above may suggest an ASD given the absence of visualized tissue between the right and left atrium in the still image. However, this may represent an artifact due to acoustic shadowing at the aortic annulus. The presence of an ASD would need to be confirmed from multiple views with or without the addition of color Doppler interrogation.

1. Baumgartner H, Hung J, Bermejo J, et al. Recommendations on the echocardiographic assessment of aortic valve stenosis: a focused update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30:372-392.

2. Booker OJ, Nanda NC. Echocardiographic assessment of Ebstein’s anomaly. Echocardiography. 2015;32 Suppl2:S177-S188.

3. Jacob D, Sibert T, Ledley G, Cho S-H, Kiliddar PG. Parachute mitral valve in an adult. J Am Coll Cardiol. 2019;73(9_suppl 1):2769.

6. Correct Answer: A. Pulmonic flow is 2× systemic flow.

Rationale: The degree of shunt flow across a ventricular septal defect can be quantified with Doppler techniques. The Qp/Qs is the amount of shunt through a defect expressed as a ratio of pulmonary to systemic flow. The Qp/Qs can be assessed echocardiographically by determining LV and right ventricular stroke volumes, which are derived from the aortic and pulmonary flow velocity profiles. The Qp/QS is normally one, indicating that pulmonic flow and systemic flow are equal and thus there is no shunting. A Qp/QS over 1.5 represents a significant shunt. A Qp/Qs of 2:1 suggests that the pulmonic flow is twice the systemic flow and is indicative of a significant shunt that should be considered for interventional or surgical closure.

1. Congenital heart disease. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:561-632.

7. Correct Answer: C. Decreased intrathoracic pressure during the release phase of Valsalva leads to transient increase in RA pressure over LA pressure and may reveal right-to-left shunting.

Rationale: Patients with cryptogenic stroke should have a TTE to assess for paradoxical embolism as a cause for cerebral ischemia. Paradoxical emboli refer to passage of a thrombus from the systemic veins to the arterial circulation via an intracardiac shunt. Paradoxical emboli most commonly occur through a PFO, which occurs in 25% to 30% of the adult population. Under normal physiologic conditions, a PFO may not lead to right-to-left shunting given the higher LA pressure compared to the RA pressure. However, right-to-left shunting may occur in patients with right-sided hypertension such as right ventricular dysfunction, tricuspid regurgitation, pulmonary hypertension, chronic obstructive pulmonary disease (COPD), and during Valsalva maneuver. The Valsalva maneuver during the strain phase causes an initial decrease in RA filling due to the increased intrathoracic pressure. After Valsalva release, the rush of blood into the right atrium causes the RA pressure to momentarily increase above the LA pressure and reverse the normal interatrial pressure gradient and may reveal right-to-left shunting. During cases of increased RA pressure, a right-to-left interatrial shunt may occur through a PFO. It is important to capture images during the strain and release phase of Valsalva maneuver.

1. Chung TO. Paradoxical embolism a diagnostic challenge and its detection during life. Circulation. 1976;53(3):565-568.

2. Rodrigues AC, Picard MH, Carbone A, et al. Importance of adequately performed Valsalva maneuver to detect patent foramen ovale during transesophageal echocardiography. J Am Soc Echocardiogr. 2013;26(11):1337-1343.

8. Correct Answer: B. Left upper extremity vein

Rationale: PLSVC occurs in about 0.5% of the general population and occurs in 1% to 10% of patients with congenital heart disease. It is a result of abnormal fetal development, which leads to blood draining from the junction of the left internal jugular and left subclavian veins directly into the coronary sinus. The diagnosis can be confirmed echocardiographically by injecting agitated saline contrast into a left upper extremity vein. The agitated saline will be visualized first in the coronary sinus before proceeding into the right atrium and right ventricle, thus B is the correct answer choice. Injection of agitated saline into the right upper or lower extremity veins would lead to visualization of bubbles in the right atrium before the coronary sinus. PLSVC in the absence of other congenital abnormalities is usually asymptomatic but may be discovered incidentally during pacemaker insertion or cannulation for cardiopulmonary bypass. Other causes of coronary sinus dilation also include atrial hypertension and tricuspid regurgitation.

1. Silbiger J. Echocardiographic examination of the posterior atrioventricular groove. Echocardiography. 2013;31:223-233.

9. Correct Answer: C. Stop dobutamine, continue volume resuscitation, and initiate alpha-1 agonist if needed

Rationale: Videos 33.1 and 33.2 show systolic anterior motion of the mitral valve, and flow acceleration in the LVOT during systole. This is typically seen in patients with hypertrophic obstructive cardiomyopathy (HOCM), which is the likely cause in our patient as well. HCM is inherited in an autosomal dominant pattern with variable penetrance and expression. Some of these patients develop LVOT obstruction causing decreased cardiac output. Thickening of the left ventricle (especially the interventricular septum) results in an alteration of blood flow, which pushes the anterior mitral valve leaflet into the LVOT, creating an obstruction. The obstruction results in acceleration of flow across the LVOT, further dragging the leaflet into the LVOT. Dobutamine is not required since contractility is adequate and further beta-1 agonism could worsen LVOT obstruction. Preload should be optimized as much as possible, keeping in mind that almost all HCM patients have some degree of diastolic dysfunction. An empty left ventricle will bring the anterior mitral leaflet closer to the LVOT and promote obstruction. Furthermore, augmenting afterload with agents that do not affect inotropy or chronotropy is ideal since this helps delay the rapid emptying of the left ventricle and counteracts the increased contractility. This is particularly important toward the end of systole when the ventricle is most empty and obstruction is at its worst.

1. Maron BJ. Clinical course and management of hypertrophic cardiomyopathy. N Engl J Med. 2018;379:655-668.

10. Correct Answer: B. Presence of systolic anterior motion of the mitral valve