In this study, first-pass radionuclide angiography (FPRNA) was performed using a digital single-crystal gamma camera. Twenty-nine men and six women (ages 43-80, mean 61 yr) underwent FPRNA in the supine position immediately prior to cardiac catheterization. Total counts/sec in the whole field-of-view in the right ventricular phase were 150,352 +/- 26,006. Background uncorrected counts in the representative cycle were 7,651 +/- 2,527 at end-diastolie and 4,904 +/- 2,314 at end-systolie. A linear correlation between FPRNA left ventricular (LV) ejection fraction and contrast LV ejection fraction gave an r = 0.95 with an s.e.e. of 0.05. Analyses of intra- and interobserver variability gave r = 0.99 and 0.98 and an s.e.e. of 0.02 and 0.03, respectively. Spearman-Rank correlation coefficients between FPRNA and contrast angiographic wall-motion scores were greater than 0.8 for all walls, while sensitivity/specificity were 0.86/0.90, 0.76/1.00, 0.76/1.00 for anterior, apical, and inferior wall-motion abnormalities, respectively. We conclude that satisfactory counting statistics for FPRNA can be obtained with a digital gamma camera, and that accurate and reproducible measurements of global and regional left ventricular function can be obtained with this technique.