[Anticoagulant treatment and dilated cardiomyopathy]

The prevalence of intracardiac thrombi in patients with dilated cardiomyopathy is very variable from one study to another, but is generally high: 20 to 25% for interatrial thrombi and 50% for intraventricular thrombi. There is also a high incidence of left atrial spontaneous contrast (30-40%). Left atrial thrombosis or spontaneous contrast is more common in atrial fibrillation, when the LA diameter is increased with low velocity intra-left atrial blood flow on Doppler examination and when there are disturbances of haemorrheological factors (increased fibrinogen levels and plasma viscosity). Ventricular thrombi are more common when the fractional shortening is decreased (< 11% = 80% of thrombi). The frequency of embolism is controversial. It varies between 1.4 and 12 events per 100 patients per year. The risk of complications is higher in patients with intracavitary thrombosis. The number of cerebral haemorrhagic complications in patients on long-term oral anticoagulants is far from negligible. Large prospective multicenter trials should be instituted, as for atrial fibrillation to evaluate systematic anticoagulation with respect to the risks. In the meantime, it would seem to be prudent to prescribe oral anticoagulants to all patients with dilated cardiomyopathy with an intracardiac thrombus and/or atrial fibrillation, and to perform echocardiography regularly when left ventricular function is very poor.