Novel algorism for the quantification of LV dyssynchrony with ECG-gated myocardial perfusion SPECT: Comparison with packaged "Phase Analysis" software

1145 Objectives Left ventricular dyssynchrony (LV-Dys) is one of the major factors for the indication of cardiac resynchronization therapy (CRT). Although packaged "phase analysis (PA)" software with ECG-gated myocardial perfusion SPECT (GMPS) has been reported to be beneficial for the assessment of LV-Dys, this software is bundled with latest workstations only. So, availability of this packaged software is limited. In this study, we developed novel algorism to quantify LV-Dys, which is available to ordinary personal computers, and compared its diagnostic value with PA software. Methods Seventeen patients with chronic heart failure underwent GMPS before and 6-month after CRT. Regional myocardial time-activity curves per-cardiac-cycle were generated with Fourier transform fitting in 20 myocardial segments. Time from R-wave to the maximum count point (= time to end-systole: TES) was measured in each segment. We adopted the maximum difference in TES among 20 segments (ΔTES) as the index of LV-Dys. We also analyzed the time to maximum wall thickening (TMWT) in 20 segments by PA software in QGS program, and calculated maximum difference of TMWT (ΔTMWT) among 20 segments. Then, we compared those indices before and after CRT. Results ΔTES showed significant positive correlation with ΔTMWT before and after CRT, respectively (before CRT: r = 0.66, P Conclusions Our original new algorism, which was comparable to packaged PA software, might contribute for the assessment of LV-Dys and might be superior to packaged PA software in terms of cost and availability