Cardiac masses and potential sources of emboli
Cardiac masses are abnormal structures within or immediately adjacent to the heart. They have to be distinguished from variants of normal cardiac structures, postoperative changes, and ultrasound artefacts. These abnormal masses may be localized in the left or right heart cavities, with different clinical manifestations according to their localization. Among the abnormal cardiac masses (thrombus, vegetations, tumours), tumours are not discussed in this chapter. Echocardiography is the main but not the only imaging technique for the evaluation of cardiac masses, and is largely available. Hence, it is indicated in patients with a systemic embolic event, searching for a cardiac source embolism. When transthoracic echocardiography is negative, transoesophageal echocardiography is indicated, in cryptogenic ischaemic events (no cause found). Right heart masses are mainly responsible for pulmonary embolisms, but may be the cause of a systemic embolus, via the atrial septum. Right heart thrombi rarely form in situ, and are hence more often venous thrombi entrapped in the right heart on their way to the pulmonary arteries. Echocardiography is mandatory in the setting of pulmonary embolism.