Employment of a single crystal gamma camera in first pass radionuclide angiography yields essential parameters of left ventricular performance. These are: global ejection fraction, end-diastolic, end-systolic and stroke volumes, regional wall motion and regional ejection fractions. Since the right anterior oblique (30 degree RAO) projection is used, results of this noninvasive method are comparable to findings from invasive contrast ventriculography. A critical evaluation of the comparative results (correlation r = 0.84 to 0.97 in global ejection fraction; r = 0.87 to 0.95 in end-diastolic volume; agreement in segmental wall motion analysis of 72 to 90%) justifies the use of a single crystal gamma camera in first pass radionuclide angiocardiography. At elevated heart rates, e.g. during exercise, the single crystal system yields information of limited value as compared with that of the multiple crystal system. As compared to other methods (e.g. equilibrium methods), short examination times (30 s) of first pass are advantageous. First pass radionuclide angiocardiography may directly precede equilibrium examinations. Within this sequence, it may be used to assess right ventricular function and lung circulation.