1. Correct Answer: D. Regional cardiac tamponade

Rationale: Cardiac tamponade in the postoperative cardiac surgical patient can present atypically, as loculated effusions or localized clot can cause compression of a part of the heart. In contrast to tamponade due to a circumferential effusion, regional cardiac tamponade has a more pronounced impact on the structures that are compressed. Notably, in many cases after cardiac surgery, transthoracic windows are inadequate to rigorously screen for cardiac tamponade and transesophageal echocardiography (TEE) is required.

In this example, there is likely posterior/lateral regional tamponade as the left heart is disproportionately impacted, with LV diastolic collapse and severe hypotension.

1. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013;26:965-1012.

2. Wann S, Passen E. Echocardiography in pericardial disease. J Am Soc Echocardiogr. 2008;21:7-13.

2. Correct Answer: B. Decrease in right ventricular diameter during inspiration

Rationale: Acute cardiac tamponade is the result of increasing external pressure placed on the cardiac chambers, usually from the accumulation of fluid in the pericardial space. However, this can occur with an open or absent pericardium such as the postoperative cardiac surgical patient with mediastinal bleeding.

1. Himelman RB, Kircher B, Rockey DC, Schiller NB. Inferior vena cava plethora with blunted respiratory response: a sensitive echocardiographic sign of cardiac tamponade. J Am Coll Cardiol. 1988;12:1470-1477.

2. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013;26:965-1012.

3. Correct Answer: C. Pericardial and pleural effusions

Rationale: Hypoechoic fluid between the descending aorta (Figure 31.2, marked by the arrow) and the heart supports the diagnosis of pericardial fluid (Figure 31.2, marked by ◊). Pleural fluid (Figure 31.2, marked by *) is unable to enter the potential space between the descending aorta and the heart. Both pericardial and pleural effusions are present in this image. Cardiac tamponade would be suggested by findings such as cardiac chamber collapse, MV/TV flow variation, and IVC plethora, none of which can be seen in this echocardiographic window.

1. Foster E. Echocardiographic evaluation of the pericardium. UpToDate. Wolters Kluwer Accessed June 26, 2019 from https://www.uptodate.com/contents/echocardiographic-evaluation-of-the-pericardium#H27.

2. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013 Sep;26(9):965-1012.e15.

4. Correct Answer: D. Reversal of diastolic hepatic vein flow during expiration

Rationale: Normally hepatic venous flow is biphasic with greater forward flow during systole than diastole. When intrathoracic pressure becomes negative during inspiration, both the peak systolic and diastolic hepatic vein flow velocities increase. As intrathoracic pressure increases during normal expiration, the systolic and diastolic hepatic venous flow is attenuated but still forward flowing. When pericardial/intracardiac pressures are increased in cardiac tamponade, overall hepatic venous flow velocities are significantly reduced (from the normal 50 to 20-40 cm/sec). Systolic hepatic vein flow now predominates because right heart pressures only decrease significantly during ventricular contraction. Diastolic hepatic vein flow reversal as observed by pulse-wave Doppler (Figure 31.3) may now be present during expiration.

TV inflow velocity increases with inspiration and decreases with expiration. Conversely, MV velocity increases with expiration and decreases with inspiration. This is true under normal circumstances but is greatly exaggerated with tamponade physiology. Respiratory cycle variation of >30% in either mitral or tricuspid inflow velocities strongly supports the diagnosis of tamponade so long as other signs of tamponade are present (e.g., presence of a pericardial effusion, signs of decreased cardiac output, and elevated right heart filling pressures).

1. Appleton CP, Hatle LK, Popp RL. Superior vena cava and hepatic vein Doppler echocardiography in healthy adults. J Am Coll Cardiol. 1987;10:1032-1039.

2. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013 Sep;26(9):965-1012.e15.

3. Mercé J, Sagristà-Sauleda J, Permanyer-Miralda G, Evangelista A, Soler-Soler J. Correlation between clinical and Doppler echocardiographic findings in patients with moderate and large pericardial effusion: implications for the diagnosis of cardiac tamponade. Am Heart J. 1999 Oct;138(4 Pt 1):759-764.

5. Correct Answer: A. Inferior vena cava (IVC) plethora

Rationale: IVC plethora on echocardiography is a highly sensitive sign of tamponade, expected in >90% of patients. A dilated IVC (>2.1 cm) with <50% reduction in diameter during inspiration suggests an elevated CVP that occurs with increased pericardial/intracardiac pressures. Although IVC plethora is very sensitive for tamponade, it is not specific as it can be present in numerous other disease states that do not involve the pericardium. Respiratory variation of MV/TV inflows, right heart collapse during diastole, and the presence of a large pericardial effusion are more specific for tamponade but less sensitive.

1. Himelman RB, Kircher B, Rockey DC, Schiller NB. Inferior vena cava plethora with blunted respiratory response: a sensitive echocardiographic sign of cardiac tamponade. J Am Coll Cardiol. 1988 Dec;12(6):1470-1477.

2. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013 Sep;26(9):965-1012.e15.

6. Correct Answer: A. A new echo-free space between the visceral and parietal pericardium present during the entire cardiac cycle

Rationale: AP refers to inflammation of the pericardial sac. In developed countries, most cases are thought to be due to a viral origin. In developing countries, cases are typically due to tuberculosis or human immunodeficiency virus (HIV). AP is a clinical diagnosis that requires at least two of the following findings:

When AP is suspected, echocardiography helps in two ways:

Because of these two reasons (especially the latter), patients suspected of having AP should undergo echocardiography within ˜24 hours of presentation.

This patient demonstrates a history and clinical findings highly suggestive of AP. Of the listed choices, only one (Answer A) is a widely accepted diagnostic criteria for AP. Answer A simply describes the presence of a new pericardial effusion: a new echo-free space between the visceral and parietal pericardium.

In fact, none of the other choices have relevance to the diagnosis of AP.

Answer B describes a situation of divergent tissue Doppler velocities along the mitral annulus: a normal lateral velocity and a subnormal medial velocity (normally, lateral e′ is ≥10 cm/sec and medial e′ ≥8 cm/sec). This can occur in patients with diastolic dysfunction. (As a side note, the opposite of this classically occurs in constrictive pericarditis: lateral mitral tissue velocities will be slow, whereas medial annulus velocities will be normal or supranormal. This occurs in CP because the lateral annulus is physically in contact with the constricted pericardium, whereas the medial mitral annulus has no physical contact with the pericardium.)

Answer C describes a finding classically found in the first phase of diastolic dysfunction (“impaired relaxation”). This finding has no bearing on the echocardiographic diagnosis of AP.

Answer D describes a normal pulmonary artery acceleration time (>120 msec). A pulmonary artery acceleration time <60 msec is associated with pulmonary hypertension. Values between 60 and 120 msec are often considered indeterminate.

1. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013;26(9):965-1012.e1015.

2. Kurzyna M, Torbicki A, Pruszczyk P, et al. Disturbed right ventricular ejection pattern as a new Doppler echocardiographic sign of acute pulmonary embolism. Am J Cardiol. 2002;90(5):507-511.

3. Nagueh SF, Smiseth OA, Appleton CP, et al. Recommendations for the evaluation of left ventricular diastolic function by echocardiography: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2016;17(12):1321-1360.

7. Correct Answer: C. Reduced left ventricle end-diastolic and end-systolic dimensions

Rationale: In a previously healthy patient with cardiac tamponade, the left ventricle will classically appear underfilled throughout the cardiac cycle (Answer C).

In a spontaneously breathing patient, during inspiration, cardiac tamponade classically causes small LV cavity dimensions and expansion of right ventricular (RV) chamber dimensions (Answer A). Classically, tamponade is associated with elevated right atrial pressures causing plethora (fixed dilation) of the IVC and hepatic veins (Answer B).

Ventricular interdependence is also common in both cardiac tamponade and CP. In both of these conditions, cardiac expansion is halted by the presence of a fixed “shell” of sorts around the heart, causing the interventricular septum to bounce toward whichever chamber has the most impaired filling at any given time in the respiratory cycle. In a spontaneously breathing patient, inspiration drops the intrathoracic pressure, which has the following immediate effects:

In a spontaneously breathing patient experiencing cardiac tamponade, this augmented filling of the right ventricle and decreased filling of the left ventricle cause septal bulging into the left ventricle. In this patient during exhalation, the filling of the two ventricles reverses and the septum bulges away from the left ventricle (toward the right ventricle). Thus, Answer D is incorrect.

1. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013;26(9):965-1012.e1015.

8. Correct Answer: A. Increase during inhalation, decrease during exhalation

Rationale: The patient had his tamponade relieved so he would presumably return back to normal physiology. Positive pressure inspiration normally increases early transmitral filling by compressing the pulmonary venous system, which increases left atrial pulmonary venous return. This is followed by a decrease in transmitral inflow during expiration. Transmitral peak “E” velocity is a surrogate for transmitral filling: the larger the flow from left atrium to left ventricle during diastole, the higher the peak “E” velocity.

Notably, the transmitral/transtricuspid flow patterns of tamponade during positive pressure ventilation remain poorly described. Whereas tamponade is associated with large respirophasic variation in transmitral and transtricuspid flow in spontaneously breathing patients, only a single small study to date has looked at these flow patterns when tamponade is exposed to positive pressure ventilation. This study used a tamponade model in 11 anesthetized dogs subjected to positive pressure ventilation.² Surprisingly, the authors found that, during positive pressure ventilation, respirophasic transmitral flow variation actually decreased in dogs subject to tamponade compared to when those same were free of tamponade. Further research is needed to better understand respirophasic changes in transmitral/transtricuspid flow when tamponade is combined with positive pressure ventilation.

1. Faehnrich JA, Noone RB, Jr., White WD, et al. Effects of positive-pressure ventilation, pericardial effusion, and cardiac tamponade on respiratory variation in transmitral flow velocities. J Cardiothorac Vasc Anesth. 2003;17(1):45-50.

2. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013;26(9):965-1012.e1015.