Relationship between left ventricular mechanical synchrony and left ventricular systolic function: A CZT-SPECT analysis

Background: CZT-SPECT has good agreement in the evaluation of mechanical synchronization compared with conventional SPECT.Theaim of this study was to evaluate the correlation between left ventricular mechanical contraction synchrony and left ventricular systolic function by gated myocardial perfusion imaging (GMPI) using Cadmium-Zine-Telluride(CZT)single photon emission computed tomography (SPECT). Methods: This retrospective study involved 371 patients （239 malesand 132 females, mean age 61.06 ± 11.78 years old）who underwent GMPI at the Nuclear Medicine Department of Shanxi Cardiovascular Hospital from January 2020 to August 2020. Systolic synchrony parameters and left ventricular systolic function parameters were calculated via Emory Cardiac Toolbox，includingPP, PSD, PHB, HS, HK, EDV, ESV, and LVEF. Based on LVEF value, patients were divided into the severe reduction group (group 1,127cases, EF<35%), moderate reduction group (group 2, 47 cases, 35% ≤ EF < 45%), mild reduction group (group 3,50 cases, 45%≤EF < 50%) and normal group (group 4 ,147 cases, EF≥50%).Differencesin PP, PSD, PHB, HS and HK between the four groups were compared using one-way ANOVA. Differences between two groups were compared usingLSD-ttest. The correlation among functional and mechanical contraction synchronism factors were analyzed using Pearson test. Results: PP, PSD, PHB, HS and HK were significantly different betweenthe four groups (F=5.20, 188.72, 202.88, 171.05, 101.36, P 0.001). PP was significantly higher in group 1, relative to group 3 (t=2.43, P<0.001) and group 4 (t=3.67, P<0.001). Pearson correlation analysis revealed that LVEF negatively correlats with PP, PSD, PHB (r = 0.194, -0.790, -0.799, all P<0.001). HS and HK showed positive correlation for LVEF (r=0.778 and 0.795, P<0.001), PSD, PHB and ESV were had good positive correlation (r=0.778, 0.795, P<0.001), PSD, PHB and EDV had good positivecorrelation (r=0.722, 0.732, P0.001). HS and HK were negatively correlated with EDV and ESV (r=-0.700～ -0.594,P<0.001). Conclusion: CZT SPECT GMPI provided left ventricular mechanical contraction synchrony parameters that correlated well with left ventricular systolic function. Worse left ventricular mechanical contraction synchrony lead to decreased LVEF , making the systolic synchrony parameters valuable in the prediction of left ventricular systolic function．