Anatomic characteristics and valvular function of the transplanted heart: transthoracic versus transesophageal echocardiographic findings.

In orthotopic heart transplantation atrial size and geometry are altered, whereas ventricles and atrioventricular valves remain structurally unchanged. To analyze the anatomy and function of the transplanted heart, 20 heart transplant recipients, with a mean age of 46.0 +/- 11.8 years, were examined with transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). Both methods showed atrial enlargement and abnormal configurations of the atria. Although valve leaflet structure appeared normal, TEE showed mitral regurgitation in 13 patients (TTE, 11), mitral prolapse in three patients (TTE, two), tricuspid regurgitation in 17 patients (TTE, 17), and tricuspid prolapse in two patients (TTE, one). Only by TEE, "pseudoaneurysms" of the donor part of the interatrial septum were found in six patients and of the receiver part in one patient, possibly as consequence of unequal thickness, asynchronous contraction, and cyclic torsion of both atrial components during the cardiac cycle. Spontaneous atrial echo contrast--again visualized only by TEE--was seen in five patients and a left atrial thrombus in three patients. Spontaneous echo contrast and thrombus formation were associated. One patient with a thrombus had had peripheral arterial embolism. We conclude that, compared with TTE, TEE offers superior imaging of cardiac anatomy, intraatrial abnormalities, and function of the atrioventricular valves. Mitral and tricuspid incompetence are frequent after orthotopic heart transplantation and may be related to abnormal atrial size and function, leading to impaired functional integrity of the valvular apparatus. The high incidence of atrial spontaneous echo contrast and thrombi suggests that antiplatelet or anticoagulant therapy may be advisable in heart transplant recipients with these findings.