A pinball game in the left atrium

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In January, 2011, a 64-year-old woman presented to us with atwo-week history of fatigue, dizziness, dyspnea on exertion, andpain in the fourth and fifth toes of her left foot. One year before, shewas diagnosed with atrial fibrillation and moderate rheumaticmitral valve stenosis. On that occasion, a transesophagealechocardiography showed a mural thrombus stuck to the posteriorwall of the left atrium, whose diameters were 3×5 cm. Therefore,anticoagulation with warfarinwas begun. A follow-up echocardiogra-phy documented the persistence of the thrombus five months beforepresentation, despite regular anticoagulation. Her thrombophiliawork-up was negative. On physical examination there was inceptivegangreneof the fingertipof the fourthtoe of her left foot. She had pal-pable bilateral femoral, popliteal, and posterior tibial pulse and a re-duced dorsalis pedis pulse. Heart auscultation was notable for aloud first heart sound, an opening snap, and a mid-diastolic murmur.The murmur changed in intensity randomly, independently by posi-tion of the patient or inspiration. Chest radiographyrevealeda dilatedleft atrium, pulmonary venous congestion, and enlarged pulmonaryartery.ECG showed atrialfibrillation. Transthoracic echocardiographyrevealed a large highly mobile mass in the left atrium. Transoesopha-geal echocardiography showed a round floating mass in the left atrialchamber,withoutevidenceof anyattachment. (Fig.1, Videos1and 2)The mass measured 2.8×2.1 cm and occasionally obstructed the mi-tral valve orifice during diastole without passing through. In systolethe mass was pushed back in the left atrium by the mitral leaflets,thus mimicking a pinball game. There was no more evidence of thevoluminous mural thrombus documented five months before. Theanticoagulation was suspended and surgery was planned. Threedays after the patient underwent cardiac surgery for removal of atrialmass and mitral valve replacement. Exploration of the left atriumrevealed a spherical, smooth, non-pedunculated thrombus free inthe atrial cavity (Fig. 2). The mitral valve was replaced using a St.Jude Medical mechanical heart valve. Amputation of affected toeswas performed concurrently. Her postoperative course was unevent-ful. Histology confirmed that the floating mass was a thrombus, cov-ered by endothelial cells.Atrial free-floating ball thrombus wasfirst described by Woodin 1814 during an autopsy of a 15-year-old girl with mitral steno-sis [1]. Free-floating thrombi are a rare condition occurring nearlyalways in the left atrium in patients with mitral stenosis, particu-larly when atrialfibrillation is present. While patients with non-valvular atrial fibrillation usually develop thrombosis of leftappendage, thrombus located in the body of the left atrium is com-moninpatientswithmitralstenosis[2]. The existence of a muralthrombus is crucial for the formation of a free-floating thrombus.In our case, we documented a pre-existing large left atrial muralthrombus few months before the presentation. This evidencestrongly suggests that it dropped off spontaneously in the atrium,maybe facilitated by anticoagulation. In fact, the thrombus wascovered by endothelium, thus suggesting it was probably old andmore resistant to dissolution. Symptoms include heart failure andsyncope for intermittent obstruction of mitral valve and systemicembolism for fragmentation. Sudden death due to incarcerationof the thrombus into the mitral orifice has been described [3].Our patient presented with dyspnea on exertion, which couldnot be explained by the moderate valve disease, and initial gan-grene of the left toes, suggesting embolization. It is likely thatsymptoms started with detachment of thrombus from the atrialwall. Although current guidelines recommend anticoagulation inpatients with atrial thrombus and mitral stenosis[4],inthispartic-ular scenario anticoagulation may not be useful and may be poten-tially harmful. Surgery is the treatment of choice since it permitsthe removal of the mass and the treatment of underling valvedisease.Supplementary materials related to this article can be foundonline at doi:10.1016/j.ijcard.2011.12.002.