Clinical Study About Left Ventricular Remodeling And Its Risk Factors After Myocardial Infarction By Radionuclide Myocardial Imaging

Objective.The aim of this study is to evaluate left ventricular(LV)remodeling and identify its risk factors in myocardial infarction(MI)patients by radionuclide myocardial imaging.Methods.This retrospective study consisted of 92 consecutive patients who had a history of definite prior MI on electrocardiography and underwent both resting gated myocardial perfusion imaging(GMPI)and myocardial metabolism imaging.95 patients who had suspected chest tightness or chest pain but no evidence of coronary artery disease with normal electrocardiogram,echocardiography,and stress/rest MPI were referred as the control group.The QGS software package(QGS 2009,Cedars Sinai Medical Center,Los Angeles,CA,USA)was used to quantitatively measure LV end-diastolic volume(LVEDV),LV end-systolic volume(LVESV),LV ejection fraction(LVEF),and summed thickening score(STS)from GMPI while the QPS software package(QPS 2009,Cedars-Sinai Medical Center,Los Angeles,CA,USA)was used to determine the total perfusion defect(TPD),viable myocardium and scar from combined GMPI and metabolism images.LV remodeling was defined as(29)mean + 2SD of LVEDV index(LVEDVi)in the control database.Logistic regression analysis was performed to identify the independent risk factors of LV remodeling in MI patients.Results.LV enlargement(LVEDVi,(84.75 ± 44.16)ml·m-2 vs.(64.44 ± 26.14)ml·m-2;LVESVi,(55.44 ± 43.89)ml·m-2 vs.(33.70 ± 23.99)ml·m-2),cardiac dysfunction(LVEF,(41.50 ± 16.69)% vs.(52.43 ± 13.73)%),wall thickening abnormalities expressed as STS(12.5(7.0-24.75)vs.6.0(1.0-13.5))and myocardial perfusion abnormalities(TPD,(21.66± 15.30)% vs.(12.72 ± 12.21)%)were more severe in the old MI patients as compared to those in subacute MI patients(all P < 0.01).Moreover,the TPD((24.37 ± 15.57)% vs.(9.43 ± 7.97)%),viable myocardium(10%(3%-23%)vs.4%(2%-7%)),scar(8%(3%-13%)vs.3%(1%-6%)),STS(19(9-29)vs.5(0-8)),the proportion of segments with reduced wall thickening in segments with normal perfusion(37.5%(20%-50%)vs.0.00%(0.00%-9.55%)),and the proportion of segments with reduced wall thickening in segments with decreased perfusion(100.00%(66.67%-100.00%)vs.33.33%(0.00%-66.67%))of LV remodeling group were significantly higher than that of no LV remodeling group(all P <0.001).STS(Odds ratio,1.296;P = 0.004)and the proportion of segments with reduced wall thickening in segments with normal perfusion(Odds ratio,1.110;P = 0.001)were identified as the independent risk factors of LV remodeling in subacute and old MI patients in the multivariate binary regression model.Conclusions.There is a time dependency of the LV remodeling process after MI,which is more extensive and severe in old MI patients than that in subacute MI patients.LV wall thickening abnormalities as expressed by STS and the proportion of segments with reduced wall thickening in segments with normal perfusion are the independent risk factors of LV remodeling in MI patients.Gated radionuclide myocardial perfusion imaging can accurately evaluate the LV remodeling and its risk factors after myocardial infarction,with a bright prospect of clinical application.