1. Answer: B. A 2003 task force of the American College of Cardiology (ACC), the American Heart Association (AHA), and the American Society of Echocardiography (ASE) gave class I recommendations for the following uses of echocardiography in known or suspected pericardial disease (available at www.acc. org/qualityandscience/clinical/statements.htm).

2. Answer: D. A plethoric inferior vena cava is a specific marker of raised central venous pressure. Although this sign may not manifest if the patient has undergone brisk diuresis or is severely dehydrated, its absence usually makes the diagnosis of advanced or hemodynamically significant pericardial diseases unlikely.

3. Answer: D. Congenital complete absence of the pericardium is associated with the enlargement of the right ventricle, excessive motion of the posterior left ventricular (LV) wall, and shift of the heart to the left, resulting in more of the right ventricle being seen on the routine left parasternal echocardiogram; these changes may result in paradoxical motion of the interventricular septum. All of these findings mimic right ventricular volume overload as seen in atrial septal defect.

4. Answer: C. Increase in tricuspid valve and decrease in mitral valve Doppler velocities on inspiration occurs in both CP and tamponade. In both CP and tamponade, the cardiac chambers operate in a fixed noncompliant space preventing the normal inspiratory decrease in intrathoracic pressure from being transmitted fully to the heart chambers. As the pressure in the extrapericardial pulmonary veins decreases normally with inspiration, a reduced pulmonary venous-to-left atrial gradient also contributes to the inspiratory decrease in LV filling. Opposite changes in the filling of the two ventricles are seen on expiration. RV diastolic collapse occurs only in tamponade, while continuous LV septal flattening during inspiration and expiration is associated with any cause of increased right-sided pressures and pulmonary hypertension. Features of pericardial tamponade are shown in Table 25-1.

5. Answer: D. Recently, new criteria for diagnosis of CP were published using five conventional echocardiographic findings. The three most important seemed to be the presence of respiration-related ventricular septal shift, preserved or increased medial mitral annular e′ velocity, and prominent hepatic vein expiratory diastolic flow reversal. Inferior vena cava plethora (maximum diameter ≥21 mm and degree of inspiratory collapse <50%), was found to be a prerequisite. The addition of a combination of ventricular septal shift and either medial e′ velocity ≥9 cm/s or hepatic vein expiratory diastolic flow reversal ratio ≥0.79 corresponded to the highest combination of sensitivity (87%) and specificity (91%).

6. Answer: D. Pericardial thickness of ≥3 mm on transesophageal echocardiography has 95% sensitivity and 86% specificity for the detection of thickened pericardium. Figure 25-14 shows a transesophageal echocardiogram (4-chamber transverse plane view) and the corresponding transaxial electron beam computed tomographic scan from a patient with a markedly thickened pericardium (up to 18 mm) over the right side of the heart (reproduced from http://circ.ahajournals.org). White arrows point to the thickened pericardium (P).

7. Answer: C. One of the features of a hemodynamically significant pericardial effusion is right ventricular diastolic collapse and/or right atrial late diastolic collapse. This 2D echocardiographically appreciated sign usually reflects that pericardial fluid has accumulated to the elastic limit of the pericardial sac, causing a significant increase in pericardial pressure. Increasing the pressure beyond this point will be at the expense of the cardiac chambers with the lowest pressures, and will be reflected as indentation of right-sided chambers during diastole. However, when rightsided pressures are abnormally high, as in severe pulmonary hypertension, pressures of the RV and RA might increase to a pressure equal to or even higher than that of the pericardial pressure, thus preventing right-sided diastolic collapse. Refer to Table 25-1.

8. Answer: A. Hepatic vein diastolic flow reversal, which increases with expiration, is a classical feature of CP. There is reversal of forward flow during expiration, since the right ventricular cavity size is reduced due to right-sided shift of the interventricular septum, becoming less compliant as the left ventricle fills more. In contrast, reversal of hepatic vein flow occurs during inspiration in restrictive cardiomyopathy.

9. Answer: A. An e′ of >8 cm/s has approximately 95% sensitivity and 96% specificity for the diagnosis of CP. In normal subjects, mitral lateral e′ velocity is higher than the medial e′ velocity. The presence of relatively normal lateral and/or septal mitral annular velocities suggests the presence of CP. However, the lateral e′ velocity is usually lower than the medial e′ velocity, resulting in annulus reversus. This finding is likely due to the tethering of the adjacent fibrotic and scarred pericardium, which influences the lateral mitral annulus of patients with CP.

10. Answer: A. In patients with CP, the pulmonary capillary wedge pressure (PCWP) is influenced by the inspiratory fall in thoracic pressure, whereas the LV pressure is shielded from respiratory pressure variations by the pericardial scar. Thus, inspiration lowers the PCWP and presumably left atrial pressure, but not LV diastolic pressure, thereby decreasing the pressure gradient for ventricular filling. The less favorable filling pressure gradient during inspiration explains the decline in filling velocity. Reciprocal changes occur in the velocity of right ventricular filling. These changes are mediated by the ventricular septum, not by increased systemic venous return and represent features of exaggerated interventricular dependence.

11. Answer: B. In CP, total cardiac volume is fixed by the noncompliant pericardium. The septum is not involved and can therefore bulge toward the left ventricle (Fig. 25-15, arrow 1), when LV volume is less than that on the right. As a result, ventricular interaction is greatly enhanced. This periodic bulging may be seen on echocardiography and represents an abnormal pattern of septal motion. In addition, the rapid filling in early diastole gives rise to additional brisk motion of the septum, which is also referred to as “septal shudder” or septal bounce (Fig. 25-15, arrow 2). It is important to differentiate septal bounce from respirophasic septal shift. A septal bounce is defined as an abrupt displacement of the interventricular septum in early diastole during each cardiac cycle. A respirophasic septal shift is defined as a posterior shift of the interventricular septum during inspiration. Hemodynamic data from the Mayo Clinic shows that the septal bounce is related to an abrupt increase in early diastolic right ventricular pressure, which surpasses left ventricular diastolic pressure during the cardiac cycle. Abnormal septal motion, however, is not specific for constriction and is also seen following cardiac surgery, in the presence of left bundle branch block or pulmonary hypertension. Tissue Doppler imaging of the ventricular septum can be used to show the polyphasic fluttering motion in constrictive pericarditis compared to the other causes of abnormal ventricular septal motion.

12. Answer: A. Demonstration of constrictive physiology and elevated filling pressure are key requisites for the diagnosis of CP and can occur in the absence of a thickened pericardium. Significant pulmonary hypertension and more than mild atrial enlargement are not typical features of CP.

13. Answer: A. Respiratory variation in mitral E velocity of ≥25% is the main diagnostic criterion for CP on Doppler echocardiography but it can also be present in patients with COPD. However, transmitral filling is usually never restrictive in COPD. In an attempt to further distinguish between these disorders, the pulsed-wave Doppler recordings of mitral and superior vena cava flow velocities can be compared. Patients with pulmonary disease have a marked increase in inspiratory superior vena cava systolic flow velocity (Fig. 25-16A, arrows), which is not seen in those with CP (Fig. 25-16B). DR = diastolic reversal.

14. Answer: C. The most common primary neoplasm of the heart associated with pericardial effusion is angiosarcoma. Nearly 80% of cardiac angiosarcomas arise as mural masses in the right atrium. Typically, they completely replace the atrial wall and fill the entire cardiac chamber. They may invade adjacent structures (e.g., vena cava, tricuspid valve). These tumors are both symptomatic and rapidly fatal. Extensive pericardial spread and encasement of the heart often occur.

15. Answer: B. The most common location of a pericardial cyst is in the right cardiophrenic angle. A pericardial cyst appears as a perfectly round fluid density, usually 2 to 4 cm in diameter, although sometimes larger.

16. Answer: A. Loculated pericardial effusions can cause significant hemodynamic compromise, often when seen as a part of effusive CP. Features of pericardial constriction can be transient and may resolve with the use of anti-inflammatory drugs. Features of cardiac tamponade are not dependent upon the volume of pericardial fluid collection but on rapidity of fluid collection. Rapid collection of small amounts of pericardial effusion can cause significant hemodynamic changes. Longstanding chronic CP may be associated with concomitant myocardial diseases or lead to epicardial fibrosis and myocardial atrophy.

17. Answer: C. Complete absence of the pericardium is associated with the enlargement of the right ventricle and shift of the heart to the left, resulting in more of the right ventricle being seen on the routine left parasternal echocardiogram. Unusual windows for obtaining traditional appearing images of the left ventricle are often needed.

18. Answer: A. Left pleural effusions can present as large echo-free spaces that resemble pericardial effusions. These can be recognized because they appear as very large posterior spaces without any anterior component. Generally, in the parasternal long-axis view, pleural effusions are located posterior to the descending aorta, whereas pericardial effusions are located anterior to the aorta.

19. Answer: B. Pericardial fluid can become loculated or compartmentalized. Loculated fluid in the pericardium or surrounding mediastinum under pressure may produce severe hemodynamic instability. Small effusions are generally confined to the region behind the left ventricle when the patient is in a supine position and may appear to vanish when the patient sits up, as they drain to the apical region.

20. Answer: C. This patient has a large loculated anterior pericardial effusion. Pericardial fluid typically appears as an anterior echo-free space on two-dimensional imaging. Pericardial fat usually can be distinguished from fluid because of subtle echogenicity resulting from the presence of fibrous material within the fat. In addition, pericardial fat remains constant in size throughout the cardiac cycle.

21. Answer: D. Figure 25-5 shows M-mode features of early diastolic collapse of the right ventricular free wall in cardiac tamponade. The yellow arrows point to right ventricular diastolic collapse. The^* denotes the pericardial effusion. The primary abnormality is compression of all cardiac chambers due to increased pericardial pressure. The pericardium has some degree of elasticity; but once the elastic limit is reached, the ventricles must compete with each other for the fixed volume determined by the increased intrapericardial pressure.

22. Answer: A. The respiratory variation of mitral and tricuspid flow velocities in cardiac tamponade is greatly increased and out of phase, reflecting the increased ventricular interdependence in which the hemodynamics of the left and right heart chambers are directly influenced by each other to a much greater degree than normal. The pathophysiology of tamponade relates to the effect of the excessive pericardial fluid limiting cardiac filling as the cardiac chambers compete with the pericardial fluid in the “fixed” and noncompliant space. Ventricular diastolic filling is reduced because of reduced inflow pressure gradients. Inspiration increases venous return to the right heart, with a simultaneous decrease in left heart filling, while expiration increases left heart filling with decrease in right heart filling. This explains the opposite respiratory variation of mitral and tricuspid inflow by Doppler echocardiography. For peak mitral E inflow velocity, the maximal drop occurs with the first beat of inspiration and the first beat of expiration and usually exceeds >30% respiratory variation. For peak tricuspid E inflow velocity, the maximal drop is on the first beat in expiration at the same time as the hepatic vein atrial reversal and usually exceeds >60% respiratory variation. Significant respiratory variation of the mitral and tricuspid inflows should not be used as a stand-alone criterion for tamponade without the presence of other features suggestive of tamponade, for example, chamber collapse, because in CP the pattern of mitral and tricuspid flow variation with respiration is comparable to that observed in cardiac tamponade; however, less in intensity (e.g., mitral inflow velocity usually not >25%-40%, and tricuspid velocity greatly increases 40%-60%) in the first beat after inspiration (Table 25-2).