free-floating thrombus in the left atrium without attachment to either the atrial wall or the mitral leaflet is an extremely rare clinical manifestation with potentially catastrophic consequences. 1 Its symptomatic presentation is variable. Fragmentation of the thrombus followed by peripheral embolization will produce ischemia or infarction in the myocardium, brain, viscera, or extremities. Partial or total occlusion of the mitral valve orifice may cause syncope and/or pulmonary congestion. 2 We present 2 cases of free-floating ball thrombus in the left atrium.
Case Reports
Case 1A 59-year-old female complaining of severe dyspnea at rest was admitted to hospital. Three years earlier, the patient was diagnosed with mitral stenosis and chronic atrial fibrillation. Auscultatory findings were typical for mitral stenosis. Transthoracic echocardiography showed a 2.5×2.5 cm free-floating ball thrombus in the left atrium and severe, calcified mitral stenosis (mitral valve area = 1.5 cm 2 , calculated by pressure half-time method) and preserved ventricular function ( Fig 1A). The thrombus rolled and tumbled in the left atrium, bounced off the atrial walls, and rotated. Emergency thrombectomy and mitral valve Circulation Journal Vol.66, September 2002 replacement (St Jude Medical (SJM) 29M) were performed successfully and her postoperative course was uneventful.The thrombus was round, smooth, nonpedunculated and 3 cm in diameter (Fig 1B) A free-floating ball thrombus in the left atrium is an unusual occurrence that may cause fatal systemic emboli or left ventricular inflow obstruction, often resulting in sudden death. The first of 2 cases was a 59-year-old female with mitral stenosis and chronic atrial fibrillation who presented with severe dyspnea. Transthoracic echocardiography revealed a free-floating ball thrombus and emergency thrombectomy and mitral valve replacement were performed successfully. A second thrombus, which was not found at preoperative examination, was attached to the anterior mitral leaflet and may have been the source of the free-floating ball thrombus. The second case was a 79-year-old female with chronic renal failure who underwent mitral valve replacement 11 years prior to admission. She had been dependent on hemodialysis for 10 years, and had suffered several recent transient cerebral ischemic attacks. Computed tomography showed a ring-shaped, high-density area in the left atrium and transthoracic echocardiography revealed a floating ball thrombus in the left atrium. Thrombectomy was performed, but the patient died as a result of postoperative pneumonia 2 months later. Case 2 appears to be the first reported case of a ball thrombus in a hemodialysis patient who had previously undergone mitral valve replacement.