Delineating Location and Size of Prior Myocardial Infarction

In order to evaluate the usefulness of thallium-201 (201TI) myocardial scintigraphy in delineating the location and size of prior myocardial infarction, 32 patients were evaluated at a mean of 7 + 2 months after infarction with a 12-lead ECG, resting 201Tl myocardial scintigram, biplane left ventriculogram and coronary angiograms. From the left ventriculogram, asynergy was quantified as percent abnormally contracting segment (% ACS), the percent of end-diastolic circumference which was either akinetic or dyskinetic. Using a computerized planimetry system, we expressed 201TI perfusion defects as a percentage of total potential thallium uptake. Of 21 patients with ECG evidence of prior transmural infarction, a 201T1 defect was present in 20 (95%), and angiographic asynergy was present in all 21 (100%). The site of prior infarction by ECG agreed with the 201Tl defect location in 24 of 32 patients (75%) and with site of angiographic asynergy in 23 of 32 patients (72%). Scintigraphic defects were present in only four of 10 patients (40%) with ACS < 6%, but scintigraphic defects