The aim of the study was to assess the relative diagnostic and prognostic accuracy of high-dose dipyridamole echocardiography test (DET: 2D-echo monitoring during dipyridamole infusion up to 0.84 mg/kg over 10') vs maximal symptom limited bicycle exercise electrocardiography test (EET) in patients with chest pain addressed to coronary angiography. We initially considered 477 consecutive patients, meeting the following inclusion criteria: 1) history of chest pain; 2) off antianginal therapy; 3) no previous myocardial infarction and/or obvious regional left ventricular dyssynergy of contraction. All patients were submitted to a DET and EET--on different days and in random order--within 1 week of coronary angiography (which was performed independently of test results). DET could not be performed in 32 patients for a poor acoustic window in resting conditions (n = 31) or for asthmatic disease requiring xanthine therapy (n = 1); EET could not be performed in 54 patients for inability to exercise, or resting electrocardiographic abnormalities making the EET interpretable. The overall feasibility was of 445/477 for DET and 423/477 for EET (93 vs 89%, p = ns). Criteria for positivity were: transient regional dyssynergy absent in the baseline examination for DET; ST segment shift greater than .15 m V from baseline for EET. Angiographically assessed coronary artery disease (CAD) was considered present when a luminal reduction greater than or equal to 50% occurred in at least 1 major coronary vessel. There were 135 pts with no significant CAD and 256 with CAD; 137 had single, 70 double, 49 triple and/or left main (15) vessel disease. The specificity was higher in DET vs EET (96 vs 59%, p less than .01). The overall sensitivity of DET was similar to EET (67 vs 69%, p = ns), with no significant differences in the subset with single (56 vs 63%, p = ns), double (74 vs 69%, p = ns) or triple (88 vs 86%, p = ns) vessel disease. Patients were followed-up for 26 +/- 22 (range 1 to 73) months considering only death and myocardial infarction as end-points. A Cox stepwise survival analysis identified the Wall Motion Score Index (an integrated semiquantitative measure of extent and severity of the dyssynergy) at peak dipyridamole as the most powerful prognostic predictor (X2 = 18.5, p less than 0001) of all invasive (number of stenotic coronary vessels, X2 = 5.8, p less than .05) and noninvasive (exercise electrocardiography positivity, p = ns) parameters.(ABSTRACT TRUNCATED AT 400 WORDS)