[Coagula tamponade as a complication of open heart surgery: the clinical significance and diagnostic value of transesophageal echocardiography].

The pathogenesis of low cardiac output failure (LOF) immediately after open heart surgery was studied in 41 patients with LOF and 15 control patients without LOF using echocardiography. In 35 patients, transesophageal echocardiography was also performed. Left ventricular (LV) contraction was impaired in 28 of the 41 LOF patients, in whom LV fractional shortening was less than 25%. In the other 13 LOF patients, however, it was greater than 25%. In 12 of these 13 patients, transesophageal echocardiography revealed that accumulating pericardial coagula were localized in the right side of the heart, deforming the right atrial and ventricular chambers. The LV end-diastolic diameter was significantly less than the control, indicating that the pericardial coagula disrupted the distension of the heart. Emergent coagulotomy was performed in 5 patients, and hemodynamic conditions were improved. In spite of "cardiac tamponade", the wall motion and pressure tracings of the right atrium and right ventricle in these patients differed from those in fluid tamponade. Therefore, this condition should be designated "coagula tamponade." In the other 22 patients in whom transesophageal echocardiography was employed, no coagula were observed. Since pericardial coagula can hardly be detected by transthoracic echocardiography, transesophageal echocardiography is indispensable for diagnosing pericardial coagula noted immediately after open heart surgery.