ECG and 2D echocardiography were studied in 64 patients with previous myocardial infarction and evidence of posterolateral fixed defect at 201 TI scintigraphy. The defect was isolated posterolateral in 47 patients (group 1), and posterolateral + inferoapical in 17 (group 2). Thirty subjects with no history of myocardial infarction and no 201 TI defects constituted the control group. We calculated sensitivity, specificity and predictive value of ECG and 2D echocardiography (pertinent wall motion abnormality) in the recognition of posterolateral infarction. ECG data were also analyzed using multivariate analysis. Among the ECG criteria, a positive T wave in V1 proved to be 100% sensitive and 76% specific both in group 1 and in group 2. At multivariate analysis, a 2-variable model (positive T wave inV1 + R/S ratio greater than or equal to 1 in V1-V2) had a sensitivity of 95 and 100% in group 1 and 2, respectively; the specificity was 80%. A 3-variable model (+ R wave duration in V1-V2 greater than or equal to 0.04 sec) proved to be less sensitive (70 and 88% in group 1 and 2, respectively), with a specificity of 97%. A pertinent dyssynergy at 2D echocardiography was 70% sensitive for posterolateral myocardial infarction in group 1, but only 29% in group 2, with a specificity of 100%. These results indicate: 1) standard ECG is more sensitive but less specific than 2D echocardiography in the recognition of previous postolateral myocardial infarction; 2) the recognition of posterolateral involvement can be frequently missed by 2D echocardiography in patients with associated inferior myocardial infarction.