[Efficacy of transesophageal echocardiography immediately after open heart surgery: diagnosis of coagula tamponade].

Massive pericardial coagula were detected by transesophageal echocardiography in some patients with low cardiac output failure immediately after open heart surgery. Characteristically, the coagula were localized anterior to the right atrium and right ventricle in all patients. The coagula could not be detected by transthoracic echocardiography. Despite of low output, absence of wall motion abnormality of the left ventricle, tachycardia, elevated atrial pressure and small left ventricular cavity lead to diagnose cardiac tamponade by pericardial coagula. Neither the right atrial nor the right ventricular wall showed collapsing motion except the area with pericardial effusion. Massive coagula in the anterior mediastinum produced similar clinical manifestation, but could be differentiated from pericardial coagula by echographic identification of the anterior pericardium. Pericardial coagula were also observed in patients with superior vena cava syndrome, but low right atrial pressure differentiated it from coagula tamponade. In all of the present patients, usual transthoracic echocardiography did not offer any sufficient images for diagnosing pericardial coagula. Transesophageal echocardiography was indispensable for detecting pericardial coagula soon after open heart surgery.