With the increasing use of cross-sectional echocardiography in patients with overt or suspected pulmonary thromboembolism in the emergency rooms, more and more right atrial thrombi are detected. These are so-called "transitthrombi" from the venous system on their way to the pulmonary arteries and they are a severe presentation of thromboembolic disease. They appear as an imminent pulmonary embolism and usually coexists with an already massive embolism. In patients were a right atrial thrombus is associated with a patent foramen ovale, paradoxical arterial embolism has been observed. Right sided heart thrombi have a high mortality rate and need immediate treatment. In our hospital we have seen 14 patients with right atrial thrombi and pulmonary embolism in a period of 6 years. Three patients had cardiac arrest with a massive pulmonary embolism, seven patients presented with a submassive embolism. All patients were treated immediately after echocardiographic diagnosis without pulmonary angiography. In about half of the cases transesophageal echocardiography was done additionally for diagnosis and monitoring. Therapeutic options were thrombectomy, fibrinolysis or anticoagulants. We treated one of our patients with thrombectomy, eleven patients with fibrinolysis and two patients with anticoagulants.