Aortoatrial fistulae diagnosed by transthoracic and transesophageal echocardiography: advantages of the transesophageal approach.

Aortoatrial fistulae are uncommon, providing a difficult diagnostic challenge both in the clinical diagnosis and in the choice of an imaging modality that fully delineates the abnormal anatomy and flow patterns. This report describes four cases of aortoatrial fistula resulting from three different underlying causes. The fistula communicated with the right atrium in three cases and the left atrium in one. We also describe the diagnostic information obtained during both transthoracic and transesophageal echocardiography and stress that full detail of the abnormal anatomy and shunting could be obtained only with the transesophageal approach, with its improved image quality of the aortic root. No extra information, other than the coronary anatomy, was obtained during aortography in the two patients who underwent cardiac catheterization. Transesophageal echocardiography should, therefore, be the investigation of choice in patients in whom there is a suspicion of aortoatrial shunting after clinical examination and routine transthoracic studies, and it may avoid the need for invasive investigation in these potentially hemodynamically unstable patients.