IMPACT OF IMMEDIATE AND DELAYED MYOCARDIAL SCINTIGRAPHY ON THERAPEUTIC DECISIONS IN SUSPECTED ACUTE MYOCARDIAL-INFARCTION

Early myocardial scintigraphic imaging has become technically feasible in patients admitted to hospital with suspected acute myocardial infa rction. After prompt injection of Tc-99m-sestamibi, subsequent scintig raphic imaging of perfused myocardium can be performed. During a 5-mon th period, 237 patients were admitted to the coronary care unit of a d istrict hospital on suspicion of acute ischaemic syndrome, and injecti on of Tc-99m-sestamibi for the performance of myocardial scintigraphy was carried out in 134 patients, on average 2 h after onset of symptom s. The investigation was repeated in 126 patients, on average 18 h aft er the injection. Three planar views were taken in the coronary care u nit with a mobile gamma camera. The prevalence of acute myocardial inf arction was 53%. The predictive value at the first scintigraphic imagi ng for a positive ol negative test for myocardial infarction 54% and 5 6%, respectively. Evert exclusion of patients with a previous infarcti on did not increase the diagnostic validity. The predictive value of a negative test, 77%, at the second scintigraphy was still insufficient to make immediate therapeutic decisions. Myocardial scintigraphy perf ormed early, on suspicion of acute myocardial infarction, cannot there fore be used to routinely as a diagnostic test prior to intervention i n unselected patients because some 90% of this patient group have myoc ardial perfusion defects.