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Chapter 12 Pericardial Diseases

CHAPTER 12 PERICARDIAL DISEASES

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FIGURE 12-1 Pathology specimens showing the double-layered pericardium with (left) and without (right) the heart in the fibrous pericardial cavity. (Courtesy W. D. Edwards, MD.)

the pericardium, the angle between the ultrasound beam and the left ventricular posterior wall (Angle − PW) at end-diastole from the parasternal long axis view and the distance between the chest wall and the most distal part of the left ventricular posterior wall (Distance − PW) from the parasternal mid-ventricular short axis view in the left and right decubitus positions can help confirm this anatomical defect (10) (Fig. 12-4). Thus, absence of the pericardium is readily recognized by these typi- cal 2D echocardiographic features and can be confirmed with computed tomography (CT) or magnetic resonance imaging (MRI) (Fig. 12-3C). PERICARDIAL CYST A pericardial cyst is a thin-walled, loculated structure filled with clear fluid (hence “spring water cyst”), usually detected as an incidental mass lesion on chest radiogra- phy or as a cystic mass on echocardiography (Fig. 12-5A). Pericardial cysts must be differentiated from loculated pericardial effusion, cardiac chamber enlargement, diaphragmatic hernia, and malignant tumors. Two- dimensional echocardiography can readily differenti- ate the echo-free content of a pericardial cyst from solid structures. The typical location of pericardial cysts in the right cardiophrenic angle is another clue, although

and complete absence of the pericardium are uncommon. It often occurs in isolation but can be associated with atrial septal defect, bicuspid aortic valve, and broncho- genic cysts. Although generally asymptomatic, partial defects in particular may cause dyspnea, chest pain (sometimes positional), syncope, or even sudden cardiac death as a result of herniation and torsion or strangulation of the heart and great vessels. Cardiac motion is exaggerated, especially the posterior wall of the left ventricle (LV). With complete absence of left pericardium, the most common situation, the heart is shifted to the left, with the apex displaced toward the axilla. Consequently, lung tissue is trapped between the descending thoracic aorta and the pulmonary artery, which along with the straight- ened left heart border creates a “Snoopy Dog” appear- ance on chest X-ray (Fig. 12-3A). The right ventricular (RV) cavity appears enlarged from the standard paraster- nal window, mimicking RV volume overload, and is situ- ated in the center of the standard apical window, with the interventricular septum deviated leftward (Fig. 12-3B and C). The combination of bulbous ventricles and elon- gated atria, as the heart is suspended from its vascular pedicle, gives rise to a “tear-drop heart” appearance in the apex down apical format (9). Since the heart moves more readily (”pendulum heart”) (9) without a portion of &RS\ULJKW ‹

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