Transesophageal Echocardiographic Study of Right Atrial Myocardial Infarction and Myocardial Viability.

In order to determine the effects of dobutamine on right atrial wall movement, two groups were studied using transesophageal echocardiography. Group A included six patients without ischemic heart disease. Group B included six patients with infarction of the inferior wall of both ventricles and abnormal wall movement of the right atrium. In group A, an increase in the amplitude of right atrial movement was observed with dobutamine at doses of 5 and 10 µg/kg per minute. In group B, infusion of dobutamine did not modify wall akinesis in three patients with right atrial infarction; in the remaining three, alterations of segmental atrial movement were evident, and their responses to dobutamine were related to the patency of right atrial coronary branches. The following conclusions were reached: (1) dobutamine has a positive inotropic effect on atrial myocardium; (2) right atrial ischemia appears in the echocardiogram as altered segmental or global wall movement; (3) dobutamine can be used in the evaluation of atrial myocardial viability.