Gelatin sponge mimicking left atrial clot in rheumatic mitral stenosis.

We report the case of a 23-year-old female who underwent balloon mitral valvotomy for severe symptomatic mitral stenosis. Following septal puncture, the patient developed cardiac tamponade, which warranted sternotomy to suture the rent in the inferior vena cava-right atrial junction. The postoperative echocardiogram revealed nonhomogenous irregular opacities within the left atrium suggesting the possibility of thrombus formation. As the patient was in sinus rhythm and peri-procedural activated clotting time was in therapeutic range, clot formation was unlikely. A review of operative notes revealed placement of absorbable hemostatic gelatin sponge within the pericardium, which was mimicking left atrial clot. This potential pitfall has to be recognized in echocardiograms, as it will avoid inappropriate anticoagulant therapy.