We validated Heart Risk View (HRV) software for estimating cardiac event probability in patients with suspected ischemic heart disease. This software is based on the results of the J-ACCESS (Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT). The HRV software can calculate stress summed scores (SSS), summed rest scores (SRS), and summed difference scores automatically using the 5 point, 20 or 17 segment model of myocardial SPECT images. It can also calculate the probability of cardiac events occurring in patients within 3 years using SSS and parameters obtained from the results of gated SPECT. Changing the threshold of % uptake for determining SPECT scores elevated the agreement of SSS (kappa = 0.269 to 0.657). Cardiac event probability calculated from Perfusion and Function Assessment for Myocardial SPECT (p-FAST) using end systolic volume (ESV), tended to be higher than that calculated from Quantitative Gated SPECT software (QGS). In contrast, cardiac event probability calculated from QGS and p-FAST using left ventricle ejection fraction (LVEF) closely agreed.