[Heart failure and arrhythmia: modalities and indications of prevention of thromboembolism].

Patients with atrial fibrillation are at risk for peripheral embolism. Congestive heart failure, a history of hypertension, previous arterial embolism or myocardial infarction are related to an increased risk for thromboembolism. Left ventricular enlargement and dysfunction, focal akinesia, protruding and mobile thrombi, spontaneous echo contrast are echocardiographic predictors of thromboembolism in patients with atrial fibrillation. Clinical trials have shown that antithrombotic therapy can reduce the rate of embolic events. In patients with heart failure the efficacy of antithrombotic therapy has not been tested in randomized, prospective trials. However in these patients oral anticoagulants are recommendable in the following conditions: atrial fibrillation; rheumatic mitral valve disease; previous thromboembolism; left ventricular enlargement and dysfunction; mobile and/or protruding thrombi; spontaneous echo contrast. The target INR in treated patients should be maintained within a range of 2 to 3 times the control. A more intense range of intensity of anticoagulation is indicated for patients with mechanical prosthetic valves or with relapsing thromboembolism. Current estimates of the effects of aspirin vary too much to allow any conclusions.