Watch out for left atrial roof thrombus.

Rheumatic mitral stenosis is often associated with thrombus formation in the left atrium (LA), especially in patients with atrial fibrillation. Although thrombus can occur anywhere within the LA, the most common site is the left atrial appendage. Therefore, it is important to carefully screen the entire LA during perioperative transesophageal echocardiography to exclude thrombus.