DIAGNOSIS OF OCCLUSION SITE IN THE LEFT ANTERIOR DESCENDING CORONARY-ARTERY IN PATIENTS WITH ANTERIOR MYOCARDIAL-INFARCTION - COMPARISON OFTL-201 MYOCARDIAL SCINTIGRAPHY AND 12-LEAD ELECTROCARDIOGRAPHY

To evaluate whether the site of occlusion/stenosis in the left anterio r descending coronary artery (LAD) could be diagnosed by noninvasive t echniques, thallium-201 myocardial scintigraphy (TMS), 12-lead electro cardiography (EGG), and coronary arteriography were performed in 33 pa tients with anterior acute myocardial infarction (AMI). The subjects w ere divided into two groups according to the location of stenosis: ie, either proximal to the first diagonal branch (PRO, n = 18), or beyond the first diagonal branch (NON-PRO, n = 15). The location of the ante rior interventricular groove was defined as 0 degrees. The extent of p ersistent perfusion defect was greater in the PRO group than in the NO N-PRO group (0.43 +/- 0.12 vs 0.31 +/- 0.14, p < 0.01). The left margi n of the defect in the basal short-axis layer was at 75 +/- 30 degrees in the PRO group and at -19 +/- 43 degrees in the NON-PRO group (p < 0.001). A defect with a left margin at >30 degrees in the basal layer was found in 94% (17/18) of the patients in the PRO group and in 6% (1 /15) of the patients in the NON-PRO group (p < 0.001). An abnormal Q w ave in leads a VL/I was found in 78% (14/18) of the patients in the PR O group and in 20% (3/15) of the patients in the NON-PRO group (p < 0. 001). The sensitivity, specificity and total predictive accuracy of de tection of proximal lesions of the LAD were 94%, 93% and 94% by TMS, a nd 78%, 80% and 79% by EGG, respectively. A significant difference in accuracy existed between TMS and ECG (p < 0.05). These data suggest th at it is possible to diagnose the site of occlusion/stenosis of the LA D as either proximal or non-proximal in patients with anterior AMI by TMS and EGG.