[Detection and surveillance of left atrial thrombosis by transesophageal echocardiography]

Out of 1,141 successive transoesophageal echocardiographic studies performed prospectively between 01/05/1993 and 31/12/1995, 26 cases of left atrial thrombosis were observed (2.2%); 5 were in the left atrium (20%), 19 in the left atrial appendage (73%) and the thrombi were in both atrium and left atrial appendage in 2 cases (7%). The 26 patients included 15 women and 11 men, with an average age of 69 +/- 16 years (range 25-89 years); 22 patients (84%) had permanent atrial fibrillation and 4 were in sinus rhythm. Only 5 of the patients were on oral anticoagulant therapy. All had underlying cardiac disease: 11 mitral valve diseases; 10 dilated cardiomyopathies; 2 hypertrophic cardiomyopathies; 3 other cardiac diseases. The indication for transoesophageal echocardiography was systemic embolism in 13 cases (50%); before D.C. cardioversion in 10 cases (38%) and before percutaneous mitral valvuloplasty in 3 cases. The thrombus was adherent in 18 cases (69%) and mobile in 8 cases (31%). Spontaneous contrast was observed in 23 cases (88%). Intravenous heparin was given as soon as the diagnosis was made. In 4 patients, thrombectomy was indicated in view of the threatening nature of the thrombus and/or the necessity for associated valve replacement. In 22 patients, heparin was relayed by oral anticoagulants on the 10th day of treatment. Control transoesophageal echocardiography was not performed because of the patient's refusal or poor general condition. The other 15 patients were reexamined 1 to 5 times between the 4th day and 12th month: a regression was observed in 13 cases (86%) which was complete in 11 and partial in 2 cases. No cases of embolism occurred during follow-up but six patients died: 1 of the operated cases and 5 of the patients treated medically (3 cardiac failures and 2 cerebral haemorrhages). The authors conclude that left atrial thrombosis is rare in the absence of classical embolic cardiac disease. With the exception of the surgical indication of a life-threatening thrombus and/or associated surgical mitral valve disease, anticoagulant therapy results in complete or partial regression of the thrombus visualised by transoesophageal echocardiography which is essential for follow-up. The prognosis depends on the severity of the underlying heart disease.