Clinical Experience

Abstract

Myocardial studies with 99mTc-labeled phosphate agents were obtained in 190 patients (208 myocardial scintigrams). Thirty-eight of 39 patients free of cardiovascular disease had no myocardial activity. Forty-two patients who met the clinical criteria for stable arteriosclerotic heart disease showed no myocardial activity. Thirty-seven patients with unstable arteriosclerotic heart disease showed ill-defined, faint-to-mild, increased activity in the region of the anterior to inferior aspect of the left ventricle. Sixty-three patients met the clinical criteria for acute myocardial infarction. Of 50 patients with transmural infarctions, 49 demonstrated focal accumulation of increased activity corresponding to the ECG localization of the infarction. Of 13 patients with subendocardial infarction, 11 demonstrated increased activity in the region of the left ventricle similar but somewhat more focal than that seen in unstable arteriosclerotic heart disease. Differentiation between these two conditions by scintigraphy alone is not always possible. Six of seven patients with myocardiopathy demonstrated faint-to-marked, diffuse, increased activity throughout the conines of a markedly enlarged cardiac silhouette. Assessment of the distribution and intensity of myocardial activity in conjunction with other clinical considerations aids in differentiation between these disease processes. Myocardial imaging with 99mTc-labeled phosphate is a simple, safe, non-invasive technique which is both practical and worthwhile in a community hospital setting.