Standard deviation of the histogram of left ventricular phase distribution (SDP-LV) obtained by radionuclide angiography (RNA) was studied in 75 acute myocardial infarction (AMI) patients, 37 with anterior or anteroseptal (Group A) and 38 with inferior, inferolateral or posterior necrosis (Group I). In order to evaluate sensitivity, specificity and accuracy of SDP-LV compared to ejection fraction (EF) and peak filling rate (PFR), 16 controls and 29 patients with coronary artery disease with normal kinesis proved by angiography were studied. Patients were also compared according to normal or abnormal EF and PFR. Sensitivity of PFR was better than those of EF and PFR (86.6% vs 38.7% and 70.6%, respectively). Specificity of SDP-LV was 89.6%, better than that of PFR (58.6%), but just less than that of EF (93.1%). The accuracy of SDP-LV turned out to be better than those of EF and PFR (87.5% vs 53.8% and 67.3%, respectively). Ejection fraction correlated with SDP-LV in the total study population (r = -0.54, P less than 0.001), and in Groups A (r = -0.44, P less than 0.01) and I (r = -0.43, P less than 0.05); SDP-LV correlated with PFR in the total population (r = -0.35, P less than 0.05), but not in Group A or I. Mean SDP-LV was higher in Group A than I and in patients with lower EF; no difference was found among patients with different PFR values.(ABSTRACT TRUNCATED AT 250 WORDS)