Objective To observe the hemodynamic changes of acute after cardiac resynchronization therapy(CRT) interruption in patients with chronic heart failure (CHF),and explore the benefit of hemodynamic of the reverse remodeling and non-reverse remodeling CHF patients during CRT.Methods 46 CHF patients who had undergone implantation of CRT device for more than 6 months were enrolled in the study.The reverse remodeling and non-reverse remodeling were identified by reduction of LV end-systolic volumes ≥ 15％.The two groups underwent echocardiography,and mitral regurgitation area (MRA),velocity time integral of aortic valve (VTI-AV),velocity time integral of mitral valve(VTI-MV),maximum rising rate of left intra-ventricular pressure(+ dp/dtmax),LVFT/T were measured in on and off mode of CRT.Hemodynamic indicators of two groups were compared in CRT on and off modes.The rate of changes of above mentioned parameters ΔMRA,ΔVTI-AV,ΔVTI-MV,Δdp/dt and ΔLVFT/T were calculated and compared in the two groups.Results MRA had significant increasing in both group after 10 minutes intereuption of CRT (P ＜0.01).Two groups had significant worsening of VTI-AV,VTI-AV,+ dp/dtmax and LVFT/T after 10 minutes interruption of CRT as compared to CRT-on mode (P ＜0.05).ΔMRA,ΔVTI-MV,Δdp/dt of reverse remodeling group significantly higher than non-reverse remodeling group(P ＜0.05).But there was no difference in ΔVTI-AV and ΔLVFT/T(P ＞0.05).Conclusions The hemodynamic index become worsening after 10 minutes interruption of CRT in both group of medium-and long-term CRT patients especially in reverse remodeling group,suggesting that patients of both groups have obtained hemodynamic benefits continuously during CRT.Reverse remodeling group get more benefits than non reverse remodeling group.