ABSTRACT
An 81 year old woman, diagnosed with rheumatic mitral valve disease and atrial fibrillation ten years previous, was admitted due to a right carotid transient ischemic attack and a acute coronary syndrome. No ST elevation was noted in the region supplied by the anterior descending artery coronary (troponin T increased and anterolateral negative waves T). In recent years years, she had maintained with (anticoagulants) an INR of 2.5-3.5; however, in the previous month the INR had dropped to 1.8. The transthoracic echocardiography showed an anterolateral hypokinesis and a globular hyperechoic mass of 2 x 4 cm which appeared to be a free floating thrombus in the dilated left atrium. This occasionally caused occlusion of the mitral valve, which itself had a severe rheumatic stenosis of approximately 1 cm2. Due to the high risk of occlusion of the mitral valve and systemic embolisms, the mitral valve replacement and thrombectomy was recommend to the patient. The patient refused this treatment and subsequently died 5 days later. This case emphasizes the importance of a suitable level of anticoagulation (INR between 2,5 and 3,5) in patients with mitral stenosis and chronic atrial fibrillation. These cases have a the high risk of thromboembolism, and urgent surgery is mandatory when a free floating left atrial thrombus is observed.