The regional contraction patterns of the left ventricle, shortly after myocardial infarction, were assessed from computer-processed scintigraphic images and histograms of the 1st transit of an i.v. injected radionuclide bolus. Patients (77) with documented myocardial infarction were injected with a compact bolus of 99mTc-pertechnetate which was coordinated with the ECG so that it arrived in the superior vena cava during diastole. Precordial activity during the initial passage was recorded in 50-ms intervals with a multicrystal scintillation camera interfaced to a dedicated minicomputer. Data frames of 4-7 cardiac cycles were summed into 1 representative cardiac cycle. In 73 of the 77 patients the images of the representative cycle, along with the corresponding time-activity curves, indicated wall-motion and stroke-volume anomalies corresponding with the ECG location of the infarct. This nontraumatic, essentially noninvasive technique permits serial examinations of the acutely ill patient for the spatial identification and estimation of suspected myocardial infarcts.