A Rare Case of “Yo-Yo”-Like Left Atrial Appendage Thrombus Causing Functional Mitral Stenosis.

Background Intracardiac thrombi are a common entity seen in clinical practice. The predisposing factors are atrial fibrillation, low cardiac output, and a low flow state as seen in patients with severely compromised systolic function and dilatation of the cardiac chambers. Anticoagulation in a patient with structural heart disease and atrial fibrillation is strongly recommended. Case Report We present a case of a 62-year-old lady seen in the ER with complaints of worsening shortness of breath over the past 2 weeks. Her past medical history was significant for hypertension, diabetes mellitus, atrial fibrillation, severe LV systolic dysfunction with NYHA class III heart failure s/p AICD insertion, and mitral regurgitation s/p mitral valve repair. Physical examination revealed a chronically ill-appearing woman in moderate respiratory distress. The first and second heart sounds were soft with a 2/6 pan systolic murmur at apex and left sternal border radiating to the left axilla. A short diastolic murmur was heard inconsistently at the apex. There was evidence of biventricular heart failure. The INR was 1.6. A transthoracic echocardiogram (TTE) revealed enlargement of all four cardiac chambers. There was global hypokinesis of the left ventricle with severely reduced left ventricular systolic function (LVEF 10%). An echo dense mass was visualized originating in the left atrium and intermittently protruding through the mitral valve. The color Doppler examination revealed moderate mitral regurgitation and moderate tricuspid regurgitation. The transesophageal echocardiogram revealed a large left atrial thrombus occupying the left atrial appendage and prolapsing back and forth through the mitral valve (like a “yo-yo”), causing an intermittent functional mitral stenosis. The patient was treated for heart failure and adequately anticoagulated. A few weeks later, a repeat TTE at another hospital revealed no evidence of the prolapsing thrombus. The INR at this time was therapeutic. Discussion Subtherapeutic anticoagulation is a common clinical problem. In some patients, such as ours, the thrombi can grow to a large size and cause functional obstruction of the valves. The mobile nature of these thrombi put the patients at a very high risk for systemic embolic events. Adequate and therapeutic anticoagulation is highly recommended to prevent such devastating complications. Although some thrombi may require surgical removal, a large percentage can be treated with adequate anticoagulation with either unfractionated or low-molecular-weight heparin and warfarin.