Radionuclide evaluation of the interventricular septum following coronary artery bypass surgery.

The cases of 25 consecutive patients who had undergone radionuclide ventriculography both before and after coronary artery bypass surgery and who had had normal septal motion before surgery were reviewed. Abnormal septal motion was present in 22 patients (88%) postoperatively. In contrast, a new motion abnormality appeared following surgery in the apical segments of only 5 of 21 patients (24%) and in the lateral segments of 1 of 22 (5%) patients. All patients improved clinically following surgery, and only two had evidence of intraoperative myocardial infarction. Postoperatively, thallium imaging revealed normal septal perfusion in all six patients who underwent this examination. Thus, it appears that ischemic injury does not always account for this phenomenon, which is a potential source of confusion in patients after coronary bypass operations. It is concluded that radionuclide ventriculography identifies the same aberration of ventricular septal motion that is seen during echocardiographic examination of patients who have undergone surgery.