Detection of anterior ischemia after inferior myocardial infarction

The presence of anterior ischemia was investigated by exercise thallium perfusion imaging and exercise radionuclide ventriculography in 21 patients who underwent coronary arteriography for inferior myocardial infarction. Anterior ischemia was detected by the occurrence of ''inferior persistent defect'' and ''anterior transient defect'' on the exercise thallium perfusion image. Furthermore, hypokinesis (phase delay and amplitude decrease) in the anterior wall was observed by exercise radionuclide ventriculography. Left ventricular ejection fraction was more significantly decreased in patients with inferior myocardial infarction accompanied by anterior ischemia than in patients with inferior myocardial infarction alone. Exercise thallium perfusion imaging and exercise radionuclide ventriculography had a high sensitivity and specificity (73% and 100%; 87% and 83% respectively) in the detection of anterior ischemia, when compared with those of exercise ECG (67% and 50%) by which it is difficult to differentiate anterior ischemia from reciprocal change. Thus, nuclear medical examinations have a high degree of diagnostic accuracy and allow non-invasive evaluation of severity of the disease. (Namekawa, K.)