The radionuclide evaluation of septal wall motion following coronary bypass surgery

We investigated the diagnostic accuracy of radionuclide global and regional left ventricular (LV) function after coronary revascularization. A consecutive series of 43 patients was studied. First-pass radionuclide angiograms were performd preoperatively (4 days±s.D. 3 days, range 1-18 days) and postoperatively (7 days±S.D. 3 days, range 3-19 days). Regional radionuclide LV function was assessed using the two-dimensional display of systole and the three- dimensional ejection fraction image. Electrocardiograms were obtained the day prior to surgery and every 8 h for the first three postoperative days. Creatine kinase (CK) and lactate dehydrogenase (LDH) isoenzymes were obtained the day prior to surgery and every 8 h for the first three postoperative days. In 39 patients who did not develop perioperative myocardial infarction by isoenzyme or ECG criteria, we found that 38 patients showed unchanged or improved global and regional LV function, while one patient without isoenzyme or ECG evidence of perioperative myocardial infarction developed a new septal wall motion abnormality. Thus, the specificity of the radionuclide radioventriculogram for new septal wall motion abnormalities was very high. In four patients who developed isoenzyme and ECG evidence of myocardial infarction, septal wall motion worsened in all four patients while global left ventricular ejection function fell significantly in three patients. Thus, the radionuclide radio ventriculogram also had high diagnostic sensitivity. In summary, contrary to past and recent reports, this investigation demonstrated that the radionuclide radioventriculogram can be used to assess global and regional LV function after coronary artery bypass surgery and furthermore, that it reliably indicates the presence of a new postoperative myocardial infarction.