Noninvasive prediction of multivessel disease after myocardial infarction.

In 65 patients with a previous transmural myocardial infarction (anterior in 33, inferior in 32), exercise thallium scanning was compared with 12-lead exercise electrocardiography to see if multivessel disease could be detected. At coronary arteriography 40 patients were shown to have multivessel disease ( greater than or equal to 70% diameter stenosis in two or three vessels) and 25 patients had one-vessel disease. On the exercise scan thallium defects corresponding to the electrocardiographic site of infarction were present in all patients. Patients wih one-vessel and multivessel disease were separated by exercise-induced angina, perfusion defects on the exercise thallium scan in more than one specific vasculare area, and a positive exercise ECG associated with angina, but not by a positive exercise ECG alone. Of the 40 patients with multivessel disease, 85% had defects in more than one vascular area on the thallium scan and 70% had a positive exercise ECG (p = NS). Of the 37 patients with thallium defects in more than one specific vascular area, 92% had multivessel disease, compared with 72% of the 39 patients who had a positive exercise ECG (p < 0.05). periinfactional ischemia was present in 38 of the 65 patients (58%) ( 14 of 25 with one-vessel disease and 24 of 40 with multivessel disease), and did not correlate with the severity of the corresponding coronary artery disease. When thallium defects that resolved were noted in a second vascular area, they were associated with a resolving rather than a constant defect in the vascular area where the infarction had occurred ( p < 0.005). In patients after a transmural myocardial infarction, multivessel disease can be better differentiated from one-vessel disease by thallium scanning than by exercise electrocardiography.