Noninvasive methods of identifying coronary artery disease are not consistently accurate. To identify abnormalities associated with angiographically determined coronary artery disease, the authors sought to quantify the utility of a new device, a digital database-driven multiphase electrocardiograph system (3DMP), which produces a computer-enhanced frequency/time-domain resting electrocardiogram, in conjunction with a 12-lead electrocardiogram. The authors compared resting 3DMP results from those of coronary angiograms to identify abnormalities associated with coronary artery disease in a random sample of 136 patients. Using a discrete-Fourier transform signal-averaging variant and a series of mathematic transformations, the computer-expert system analyzed signals in the 0.1- to 50-Hz range. The system identified abnormalities by comparing results with a 21,000-patient database culled from predicate research. The system detected abnormalities in 96.0% of patients subsequently found to have 70% or greater stenosis by angiography. For patients with a 40% or less times a more than 50% occlusion, the system detected abnormalities in 75% of cases. For patients with a 50% or less times a 70% or less occlusion, it detected abnormalities in 90% of cases. Overall sensitivity for the study was 93.3% (positive predictive value, 91.2%; specificity, 83%; negative predictive value, 86.7%). No gender differences were detected. A 3DMP electrocardiograph system combined with 12-lead electrocardiography appears to have measurable, diagnostic utility in identifying 3DMP abnormalities associated with coronary artery disease, and warrants further study.