Giant left atrium with spontaneous echo contrast: a harbinger of thromboembolic phenomenon.

DESCRIPTION A 25-year-old man presented with worsening dyspnoea on exertion of 5 months duration along with two episodes of thromboembolic stroke to the left side of the body over a span of the last 2 months. The patient had a history suggestive of rheumatic heart disease. On cardiac auscultation, a long rumbling mid-diastolic murmur was heard. ECG showed atrial fibrillation. Chest roentgenogram (figure 1A) revealed cardiomegaly with enlarged left atrial appendage (white arrows), splaying of carinal angle (thick black arrows) and double-density sign (black arrows) along the right cardiac border suggesting left atrium (LA; black arrows). Transthoracic echocardiogram revealed a grossly dilated LA (measuring 18.4×11.1 cm) having dense swirling spontaneous echo contrast (SEC; figure 1B, video 1), severe mitral stenosis and moderate mitral regurgitation with mitral valve orifice area of 0.9 cm. Interestingly, the SEC in LA (thin white arrow) was partially cleared of (thick white arrow) by the mitral regurgitation jet, thus giving the appearance of negative contrast (figure 2; video 2). Postmitral valve replacement, the echocardiogram revealed the regression of LA size and disappearance of the SEC (figure 3). According to Isomura et al, the giant LA is defined as diameter more than 8 cm. The SEC is an echogenic swirling pattern of blood flow, caused by an increased ultrasonic backscatter from the aggregation of the cellular components of blood in the conditions of blood stasis or low-velocity blood flow and has been associated with a higher risk of thromboembolism and cerebrovascular accident. Learning points