FIG 52.1 Left ventricular myxoma in an adult It is easy to see how parts of the tumor can fragment and embolize to the systemic circulation FIG 52.2 Section across an intramural coronary artery that is completely occluded by a thrombus detached from the surface of an intracardiac myxoma In general, left-sided tumors embolize to the systemic circulation Hence they may affect almost any organ, even the heart itself.18 Sudden occlusion of a peripheral artery should always alert to the possibility of embolization from a primary intracardiac tumor and should alert to the possibility of cerebral embolism.16 Moreover, multiple systemic embolization may mimic systemic vasculitis or infective endocarditis, particularly when producing systemic manifestations Primary tumors in the right heart chambers may cause pulmonary embolism.19 This may be indistinguishable from pulmonary embolism secondary to venous thromboembolism Perfusion defects in the lung due to embolization from a tumor do not usually resolve within a few weeks, as they do with venous embolization Embolization from a tumor may also be suggested by complete absence of flow to one lung in the presence of a normal perfusion scan on the opposite lung This is most unusual in patients with recurrent pulmonary venous thromboembolism Cardiac Manifestations The cardiac events are largely dependent on the location and extent of the tumor within the heart Tumors that are localized within the myocardium may be asymptomatic and discovered incidentally on imaging studies or at autopsy Detection of a cardiac mass on routine obstetric sonographic scan is often the initial finding in fetuses.1 Arrhythmias Disturbances of cardiac rhythm can be the first manifestation of a primary cardiac tumor.20 Should the tumor be located in the region of the atrioventricular node or conduction axis, even small tumors may produce disturbances of atrioventricular conduction Complete atrioventricular block and sudden death are seen as the extreme clinical manifestation, especially for rhabdomyomas.1 Moreover, the intramural location of primary tumors may underlie a wide variety of disturbances of rhythm, including atrial fibrillation or flutter, paroxysmal atrial tachycardia, atrioventricular junctional rhythm, partial or complete atrioventricular block, supraventricular tachycardia, atrial and ventricular premature beats, ventricular tachycardia, and ventricular fibrillation.20–23 Cardiac Failure and Pericardial Effusion Infiltrative tumors of the myocardium can cause hemodynamic compromise This tends to occur late in the clinical course when there is substantial involvement of the myocardium or pericardium (Fig 52.3), producing symptoms of cardiac failure consequent to systolic and/or diastolic dysfunction.1 In some instances, the clinical presentation may mimic that of dilated, restrictive, or hypertrophic cardiomyopathy.24,25 Pericardial exudates, eventually with cardiac tamponade, may be the first symptom of the epicardial location of a tumor.26,27 This is mainly seen with teratomas, vascular tumors, malignant tumors, and secondary lesions