Eustachian Valve

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Chapter 13: THE ECHOCARDIOGRAM CARDIAC MASSES, THROMBI, AND TUMORS Normal Variants and Masses of Uncertain Significance

When an abnormally localized accumulation of dense reflectances appears on the echocardiogram, it is said to represent a mass. Echocardiographic masses may be caused by technical artifacts or anomalous structures, but they are of greatest significance in representing true lesions of the heart such as tumors, thrombi, and vegetations. Echocardiography is the procedure of choice for the detection and evaluation of cardiac mass lesions; often, it is the only modality capable of delineating small lesions such as papillary fibroelastomas.625 Accordingly, echocardiographic examinations are commonly performed to search for embolic sources, particularly in patients with cerebral ischemic events.

A number of technical artifacts are capable of appearing as masses on echocardiogram. For example, side lobe signals, reverberations, and noise artifact may lead to accumulations of ultrasonic reflectance within the cavities or adjacent to the myocardium of the heart.20,2! Such structures usually lack distinct borders, do not move appropriately through the cardiac cycle, lack identifiable attachments to endocardial surfaces, and cannot be visualized in all views and at all depth settings. In seeking a way to distinguish artifacts from LV thrombi (a common clinical dilemma) the absence of wall motion abnormalities is of particular value.626

Several benign normal variant findings can be observed during echocardiographic examination and must be distinguished from pathologic lesions. Thus, many adults manifest persistence of the eustachian valve (Fig. 13-125), a thin ridge of tissue at the junction of the inferior vena cava and right atrium.627,628 The eustachian valve appears as a long, linear, freely mobile structure in the right atrium at the mouth of the inferior vena cava and is nearly always benign (although infective involvement has been reported).629,630 An additional embryonic remnant that may be seen in the posterior right atrium is the Chiari network, which typically appears as a weblike mobile structure.631,632 In some individuals, RV hypertrophy may produce significant enlargement of the RV moderator band coursing along the interventricular septum to the apex of the RV.633 Similarly, false chordae tendineae ("heartstrings") can occasionally be visualized as linear structures spanning the LV cavity attached to endomyocardium at both ends (Fig. 13-126).634,635 Neither of the foregoing lesions has been conclusively associated with morbidity or mortality. On occasion, LV hypertrophy or hypertrophied papillary muscles may simulate cardiac mass lesions.633 Although TEE provides enhanced sensitivity and resolution in the delineation of cardiac mass lesions, this technique may be associated with variants and artifacts of its own.636,637

Eustachian Valve Ivc Echo

Figure 13-125: Right ventricular inflow view showing a prominent eustachian valve (arrow) at the junction of the inferior vena cava (IVC) and the right atrium (RA). RV = right ventricle; CS = coronary sinus. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia; Saunders; 1996:452-480, with permission.)

Figure 13-125: Right ventricular inflow view showing a prominent eustachian valve (arrow) at the junction of the inferior vena cava (IVC) and the right atrium (RA). RV = right ventricle; CS = coronary sinus. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia; Saunders; 1996:452-480, with permission.)

Coronary Sinus Echocardiogram Apical

Figure 13-126: Apical four-chamber view demonstrating a false chord (arrow) within the left ventricle (LV). LA = left atrium; RA = right atrium; RV = right ventricle. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452-480, with permission.)

Figure 13-126: Apical four-chamber view demonstrating a false chord (arrow) within the left ventricle (LV). LA = left atrium; RA = right atrium; RV = right ventricle. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452-480, with permission.)

A variety of foreign bodies and iatrogenically induced anatomic alterations may be visualized on echocardiogram and must be distinguished from pathologic lesions. Intracardiac catheters, pacemaker leads (Fig. 13-127), prosthetic valves or patches, and atrial suture lines after cardiac transplantation can be visualized during echocardiographic examination.638,639 These structures are usually easily recognized due to the highly reflective properties of the foreign material, which result in bright echoes, reverberations, and shadowing behind the structures. In this regard, endomyocardial biotomes and pericardiocentesis catheters can be readily visualized by cardiac ultrasound, and echocardiography can be employed to guide procedures utilizing these instruments in lieu of fluoroscopy.640,641 Last, a variety of manufactured objects that have penetrated the heart have been described on echocardiography, including bullets, pellets, and nails.642

Bullets Myocardium

Figure 13-127: Subcostal four-chamber image demonstrating a pacemaker wire (arrows) in the right heart. RA = right atrium; LA = left atrium; LV = left ventricle.

Several morphologic changes involving the interatrial septum are often considered under the classification of cardiac mass lesions of uncertain significance. Aneurysms of the interatrial septum have been reported in about 1 percent of the population and are recognized on echocardiogram as a protrusion of the interatrial septum of at least 1.5 cm from its longitudinal plane dividing the left and right atrium (B+ffl? Fig. 13-128).643'644 Although usually benign, interatrial septal aneurysms are often associated with a patent foramen ovale and have been implicated as a source of cardiogenic emboli.645 Interatrial septal aneurysms may be detected by TTE, but they are more readily imaged by the transesophageal approach.644 Lipomatous hypertrophy of the interatrial septum, or accumulation of adipose tissue within this structure, is not an uncommon finding in elderly individuals. Lipomatous hypertrophy appears as a highly reflective thickening of the interatrial septum that typically spares the foramen ovale, thereby creating a characteristic dumbbell echocardiographic appearance.646,647 No significant consequences or sequelae have been attributed to lipomatous infiltration of the interatrial septum.

Intracardiac Thrombi

Intracardiac thrombi occur commonly in a variety of cardiovascular disorders, may be visualized in any chamber of the heart, and frequently result in embolic events.648 The major factors that predispose to the formation of intracardiac thrombi include localized stasis of flow, low cardiac output, and cardiac injury. In addition, migration of venous thrombi may also result in intracardiac clots.649,650 The appearance of intracardiac thrombi may vary considerably, and although they are typically attached to the endocardium, unrestricted and freely mobile thrombi occasionally may be encountered (particularly in the setting of valvular stenosis which prevents exit of the thrombus from the heart).651 Thrombi typically have identifiable borders and may be layered and homogeneous or heterogeneous, with areas of central liquefaction (Figs. 13-129 and 13-130).651,652

Apical Thrombus EchoEchocardiogram Apical Thrombus Pictures
Figure 13-129: Magnified apical view of a large thrombus (T) in the apex of the left ventricle (LV). Although the thrombus is fairly homogeneous, its border is more echo-dense (arrows).
Fibroelastoma Echo

Figure 13-130: Parasternal long-axis view of a large mobile thrombus (arrow) attached to the anteroseptal segment of the left ventricle (LV). LVOT = left ventricular outflow tract; LA = left atrium. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452-480, with permission.)

Figure 13-130: Parasternal long-axis view of a large mobile thrombus (arrow) attached to the anteroseptal segment of the left ventricle (LV). LVOT = left ventricular outflow tract; LA = left atrium. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452-480, with permission.)

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Essentials of Human Physiology

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