Giant Left Atrial Thrombus with Double Coronary Vascularization

Rheumatic valvular disease, especially mitral stenosis (MS) and atrial fibrillation (AF), are the main factors related to the formation of left atrial (LA) thrombi1-6. Its incidence can range from 16 to 64%, and the most affected site is the left atrial appendage1,7. Systemic embolism is responsible for 10 to 45% of the complications, being the most frequent clinical presentation1. Despite being rare, the mechanical mitral valve obstruction caused by thrombus may be considered as potentially severe, especially among those patients with previous MS. The clinical manifestations of this condition are variable, presenting from worsened functional class (NYHA) to cardiogenic shock2. The left atrial thrombus related to MS, even if rarely, may present as a large and organized mass with undistinguishable characteristics from vascularized tumors, especially the atrial myxoma. Clinical and echocardiographic aspects may not be sufficiently specific to distinguish one from the other safely, and additional examinations are often required7. This is the case of a patient with moderate rheumatic MS and no anticoagulation for AF, with a large thrombus organized in LA mimicking an atrial tumor, with difficult clinical differentiation by complementary examinations.