DIPYRIDAMOLE ELECTROCARDIOGRAPHY TEST FOR THE DETECTION OF SEVERE CORONARY-ARTERY STENOSES

To investigate the relationship between dipyridamole-induced ST depression and the severity of coronary artery stenosis, the dipyridamole injection test (D) at 0.568 mg/kg/4 min, and the symptom-limited treadmill exercise test (T) were performed separately in 16 normal volunteers and 167 patients who underwent coronary arteriography [91 patients without myocardial infarction (non-MI group) and 76 patients with previous myocardial infarction (MI group)]. Standard 12-lead electrocardiogram and body surface mapping of 87 leads were recorded in both tests. None of the normal volunteers had significant ST depression (greater-than-or-equal-to 0.10 mV) in D or T. Regarding the non-MI group, D had as high an incidence of ST depression as T (83% vs 93%) in patients with maximal coronary stenosis greater-than-or-equal-to 90%, while in those with maximum coronary stenosis < 90%, D had a lower incidence of ST depression than T (16% vs 48%, p < 0.01). For the Ml group, the incidence of ST depression was compared to the maximal coronary artery stenosis supplying the non-infarcted area. In patients with maximal coronary artery stenosis greater-than-or-equal-to 90%, D had as high an incidence of ST depression as T (71% vs 64%). While, D had a lower incidence of ST depression than T (19% vs 35%, p < 0.05) in those with maximum coronary artery stenosis < 90%. For the diagnosis of coronary artery stenosis of greater-than-or-equal-to 90%, D had as high sensitivity (non-MI group, 82% vs 93%; Ml group, 71% vs 64%) and higher specificity (non-MI group, 84% vs 52%, p < 0.01; MI group, 81% vs 65%, p < 0.05) compared with T. This study demonstrated that dipyridamole ECG is a sensitive and specific test to detect severe coronary artery stenosis.