Evaluation Of Left Ventricular Mechanical Dyssynchrony And Its Influencing Factors In Patients With Myocardial Infarction By Radionuclide Myocardial Imaging

Objective:Left ventricular mechanical dyssynchrony?LVMD?is an important factor of heart failure and all-cause mortality in patients with myocardial infarction?MI?.The aim of this study is to identify the influencing factors of LVMD in MI patients by radionuclide myocardial imaging.Method:This study consisted of 91 patients who had a history of definite prior MI and underwent both ^99mTc-MIBI single photon emission computed tomography?SPECT?gated myocardial perfusion imaging?GMPI?and ¹⁸F-FDG positron emission tomography?PET?myocardial metabolic imaging at the Third Affiliated Hospital of Soochow University from October 2010 to November 2016.Left ventricular functional and LVMD parameters were measured from SPECT GMPI,while myocardial viability was assessed by the integral quantitative analysis of SPECT GMPI and ¹⁸F-FDG PET.LVMD was defined as>mean+2SD of phase bandwidth?BW?in the control group.The differences of the related clinical characteristics,cardiac function indexes,hibernating myocardium,and scar between LVMD group and non-LVMD group were compared.The correlations between BW and LVEF,hibernating myocardium,and scar were analyzed in MI patients.Then to screen the influencing factors of LVMD and further validate whether there existed significant relationship between the improvement of LVMD and preoperative hibernating myocardium in the MI patients who had underwent coronary artery bypass graft?CABG?.Results:The comparison between MI patients and healthy controls show that MI patients had significantly higher BW?68.9±42.4 vs 37.2±11.7;P<0.001?,SD?20.6±12.4 vs 11.8±5.4;P<0.001?,but significantly lower LVEF?48.0±15.9 vs 68.9±9.5%;P<0.001?than the healthy controls.LVMD was present in 37/91?40.7%?MI patients.Hibernating myocardium?SPECT/PET mismatch?and scar in patients with LVMD were significantly higher than those without LVMD?15.24±11.26%vs 4.89±5.41%,P<0.001;11.11±9.42%vs 4.72±5.71%,P<0.001;respectively?.BW correlated with LVEF,hibernating myocardium and scar?r=-0.689;0.542,0.469,All P<0.001;respectively?.In the univariate regression model,NYHA class,QRS duration,LVEDV,hibernating myocardium,and scar were identified as the risk factors of LVMD in MI patients,whereas age,gender,and other clinical data were not predictive for LVMD.The multivariate logistic regression analysis showed that hibernating myocardium was an independent factor of LVMD in MI patients?OR=1.110,P=0.007?.Furthermore,the MI patients underwent a significant improvement of LVMD after CABG at a median follow-up time of 6 months[BW:?41.21±15.54°vs 55.26±30.24°;P<0.05?;SD:?13.83±6.69 vs 17.18±8.88,P<0.05?],and the improvement of PBW??PBW?after CABG at a median follow-up time of 6 months was significantly related with the amount of preoperative hibernating myocardium?r=0.485,P=0.002?.Conclusion:MI patients with LVMD show significantly larger amounts of hibernating myocardium and scar as compared to those without LVMD.Hibernating myocardium is independently associated with LVMD in MI patients.The improvement of LVMD after CABG at a median follow-up time of 6 months was related with the amount of preoperative hibernating myocardium.