Diagnosis of atrial situs by transesophageal echocardiography.

In a prospective investigation, direct visualization of both atrial appendages was attempted during transesophageal echocardiographic studies in 132 patients with congenital heart disease. High quality cross-sectional images delineating the unique morphologic details of both atrial appendages were obtained in every patient. Abnormal cardiac position such as dextrocardia (four patients) or mesocardia (two patients) did not pose any problems for transesophageal assessment of both atrial appendages. Thus, direct diagnosis of atrial situs was possible in every patient. Atrial situs solitus was present in 127 patients studied. Three patients were found to have situs inversus, one had left atrial isomerism and one had right atrial isomerism. No patient with juxtaposed atrial appendages was encountered. All patients had prior subcostal ultrasound scans for assessment of the morphology and relation of the suprarenal abdominal great vessels and the related patterns of hepatic venous drainage. Patients with abnormal atrial situs had correlative high kilovoltage filter beam radiography for assessment of bronchus morphology. The results of situs determination obtained by either method were in agreement. In this series, transesophageal echocardiography allowed the direct and accurate visualization of both atrial appendages and the determination of atrial situs in all patients studied. Transesophageal echocardiography may prove to be the most reliable in vivo technique for determination of atrial situs.