Non-invasive detection of coronary artery disease by body surface electrocardiographic mapping after dipyridamole infusion

Electrocardiographic changes after dipyridamole infusion (0.568mg/kg/4min) were studied in 41 patients with coronary artery disease and compared with those after submaximal treadmill exercise by use of the body surface mapping technique. Patients were divided into three groups; 19 patients without myocardial infarction (non-MI group), 14 with anterior infarction (ANT-MI) and eight with inferior infarction (INF-MI). Eightyseven unipolar electrocardiograms (ECGs) distributed over the entire thoracic surface were simultaneously recorded. After dipyridamole, ischemic ST-segment depression (0.05mV or more) was observed in 84% of the non-MI group, 29% of the ANT-MI group, 63% of the INF-MI group and 61% of the total population. Exercise-induced ST depression was observed in 84% of the non-MI group, 43% of the ANT-MI group, 38% of the INF-MI group and 61% of the total. For individual patients, there were no obvious differences between the body surface distribution of ST depression in both tests. The increase in pressure rate product after dipyridamole was significantly less than that during the treadmill exercise. The data suggest that the dipyridamole-induced myocardial ischemia is caused by the inhomogenous distribution of myocardial blood flow. We conclude that the dipyridamole ECG test is as useful as the exercise ECG test for the assessment of coronary artery disease.