Background and objectives Right ventricular apical(RVA)pacing has been reported impairing left ventricular(LV)performance.Alternative pacing sites in right ventricle(RV)has been explored to obtain better cardiac funct...Background and objectives Right ventricular apical(RVA)pacing has been reported impairing left ventricular(LV)performance.Alternative pacing sites in right ventricle(RV)has been explored to obtain better cardiac function.Our study was designed to compare the hemodynamic effects of right ventricular septal(RVS)pacing with RVA pacing.Methods Ten elderly patients with chronic atrial fibrillation(AF)and long RR interval or slow ventricular response(VR)received VVI pacing.The hemodynamic difference between RVS and RVA pacing were examined by transthoracic echocardiography(TTE).Results Pacing leads were implanted successfully at the RVA and then RVS in all patients without complication.The left ventricular(LV)parameters,measured during RVA pacing including left ventricular ejection fraction(LVEF),FS,stroke volume(SV)and peak E wave velocity(EV)were decreased significantly compared to baseline data,while during RVS pacing,they were significantly better than those during RVA pacing.However,after 3-6 weeks there was no statistical significant difference between pre-and post-RVS pacing.Conclusions The LV hemodynamic parameters during RVA pacing were significantly worse than baseline data.The short term LV hemodynamic parameters of RVS pacing were significantly better than those of RVA pacing;RVS pacing could improve the hemodynamic effect through maintaining normal ventricular activation sequence and biventricular contraction synchrony in patients with chronic AF and slow ventricular response.展开更多
Objective In order to provide the maximum benefit of cardiac resynchronization therapy(CRT),we tried to use an echocardiography method to optimize the atrioventricular and interventricular delay.Methods The study incl...Objective In order to provide the maximum benefit of cardiac resynchronization therapy(CRT),we tried to use an echocardiography method to optimize the atrioventricular and interventricular delay.Methods The study included 6 patients who underwent implantation of biventricular pacemakers for drug-resistant heart failure.Two-dimensional echocardiography and tissue Doppler imaging were carried out before and after the pacemaker implantation.The optimal AV delay was defined as the AV delay resulting in maximum timevelocity integral(TVI)of transmitral filling flow,the longest left ventricular filling time(LVFT)and the minimum mitral regurgitation(MR).The optimal VV delay was defined as the VV delay producing the maximum LV synchrony and the largest aortic TVI.Results CRT was successfully performed in all patients.After pacemaker implantation,an acute improvement in left ventricular ejection fraction(LVEF)was observed from 26.5%to 35%.Meanwhile,the QRS duration decreased from 170ms to 150ms.The optimal AV delay was programmed at 130,120,120,120,150 and 110ms respectively with heart rate corrected,LVFT significantly lengthened and TVI of MR decreased(non-optimal vs optimal AV delay:LVFT:469ms vs 523ms;TVI of MR:16.43cm vs 13.06cm,P<0.05).The optimal VV delay was programmed at 4,4,4,8,12 and 8ms with LV preactivation respectively.Programming the optimal VV delay increased the aortic TVI from 17.33cm up to 21.42cm(P<0.05).In the septal and lateral wall,peak systolic velocities improved from2.70cm/s to 3.02cm/s(P>0.05)and froml.31cm/s to 2.50cm/s(P<0.05)respectively.The septal-to-lateral delay in peak velocity improved from 56.4ms to 13.3ms after CRT(P<0.01).Conclusions Optimization of AV and VV delays may further enhance the efficacy of CRT.However,there was interindividual variability of optimal values,warranting individual patient examination.展开更多
Persisters refer to genetically drug susceptible quiescent(non-growing or slow growing)bacteria that survive in stress environments such as antibiotic exposure,acidic and starvation conditions.These cells can regrow a...Persisters refer to genetically drug susceptible quiescent(non-growing or slow growing)bacteria that survive in stress environments such as antibiotic exposure,acidic and starvation conditions.These cells can regrow after stress removal and remain susceptible to the same stress.Persisters are underlying the problems of treating chronic and persistent infections and relapse infections after treatment,drug resistance development,and biofilm infections,and pose significant challenges for effective treatments.Understanding the characteristics and the exact mechanisms of persister formation,especially the key molecules that affect the formation and survival of the persisters is critical to more effective treatment of chronic and persistent infections.Currently,genes related to persister formation and survival are being discovered and confirmed,but the mechanisms by which bacteria form persisters are very complex,and there are still many unanswered questions.This article comprehensively summarizes the historical background of bacterial persisters,details their complex characteristics and their relationship with antibiotic tolerant and resistant bacteria,systematically elucidates the interplay between various bacterial biological processes and the formation of persister cells,as well as consolidates the diverse anti-persister compounds and treatments.We hope to provide theoretical background for in-depth research on mechanisms of persisters and suggest new ideas for choosing strategies for more effective treatmentofpersistent infections.展开更多
文摘Background and objectives Right ventricular apical(RVA)pacing has been reported impairing left ventricular(LV)performance.Alternative pacing sites in right ventricle(RV)has been explored to obtain better cardiac function.Our study was designed to compare the hemodynamic effects of right ventricular septal(RVS)pacing with RVA pacing.Methods Ten elderly patients with chronic atrial fibrillation(AF)and long RR interval or slow ventricular response(VR)received VVI pacing.The hemodynamic difference between RVS and RVA pacing were examined by transthoracic echocardiography(TTE).Results Pacing leads were implanted successfully at the RVA and then RVS in all patients without complication.The left ventricular(LV)parameters,measured during RVA pacing including left ventricular ejection fraction(LVEF),FS,stroke volume(SV)and peak E wave velocity(EV)were decreased significantly compared to baseline data,while during RVS pacing,they were significantly better than those during RVA pacing.However,after 3-6 weeks there was no statistical significant difference between pre-and post-RVS pacing.Conclusions The LV hemodynamic parameters during RVA pacing were significantly worse than baseline data.The short term LV hemodynamic parameters of RVS pacing were significantly better than those of RVA pacing;RVS pacing could improve the hemodynamic effect through maintaining normal ventricular activation sequence and biventricular contraction synchrony in patients with chronic AF and slow ventricular response.
文摘Objective In order to provide the maximum benefit of cardiac resynchronization therapy(CRT),we tried to use an echocardiography method to optimize the atrioventricular and interventricular delay.Methods The study included 6 patients who underwent implantation of biventricular pacemakers for drug-resistant heart failure.Two-dimensional echocardiography and tissue Doppler imaging were carried out before and after the pacemaker implantation.The optimal AV delay was defined as the AV delay resulting in maximum timevelocity integral(TVI)of transmitral filling flow,the longest left ventricular filling time(LVFT)and the minimum mitral regurgitation(MR).The optimal VV delay was defined as the VV delay producing the maximum LV synchrony and the largest aortic TVI.Results CRT was successfully performed in all patients.After pacemaker implantation,an acute improvement in left ventricular ejection fraction(LVEF)was observed from 26.5%to 35%.Meanwhile,the QRS duration decreased from 170ms to 150ms.The optimal AV delay was programmed at 130,120,120,120,150 and 110ms respectively with heart rate corrected,LVFT significantly lengthened and TVI of MR decreased(non-optimal vs optimal AV delay:LVFT:469ms vs 523ms;TVI of MR:16.43cm vs 13.06cm,P<0.05).The optimal VV delay was programmed at 4,4,4,8,12 and 8ms with LV preactivation respectively.Programming the optimal VV delay increased the aortic TVI from 17.33cm up to 21.42cm(P<0.05).In the septal and lateral wall,peak systolic velocities improved from2.70cm/s to 3.02cm/s(P>0.05)and froml.31cm/s to 2.50cm/s(P<0.05)respectively.The septal-to-lateral delay in peak velocity improved from 56.4ms to 13.3ms after CRT(P<0.01).Conclusions Optimization of AV and VV delays may further enhance the efficacy of CRT.However,there was interindividual variability of optimal values,warranting individual patient examination.
基金We acknowledge the support by Zhejiang Provincial Natural Science Foundation of China(LY24H290004)National Natural Science Foundation of China Youth Foundation(81701969)+4 种基金Natural Science Youth Exploration Program(2022JKZKTS03)Open fund for the State Key Laboratory of Pathogenic Biology of Animal Diseases(SKLVEB2021KFKT002)for HXNNational Center for Infectious Disease startup fund(B2022011-1)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2021R01012)Jinan Microecological Biomedicine Shandong Laboratory project(UNL-2022050B)for YZ.
文摘Persisters refer to genetically drug susceptible quiescent(non-growing or slow growing)bacteria that survive in stress environments such as antibiotic exposure,acidic and starvation conditions.These cells can regrow after stress removal and remain susceptible to the same stress.Persisters are underlying the problems of treating chronic and persistent infections and relapse infections after treatment,drug resistance development,and biofilm infections,and pose significant challenges for effective treatments.Understanding the characteristics and the exact mechanisms of persister formation,especially the key molecules that affect the formation and survival of the persisters is critical to more effective treatment of chronic and persistent infections.Currently,genes related to persister formation and survival are being discovered and confirmed,but the mechanisms by which bacteria form persisters are very complex,and there are still many unanswered questions.This article comprehensively summarizes the historical background of bacterial persisters,details their complex characteristics and their relationship with antibiotic tolerant and resistant bacteria,systematically elucidates the interplay between various bacterial biological processes and the formation of persister cells,as well as consolidates the diverse anti-persister compounds and treatments.We hope to provide theoretical background for in-depth research on mechanisms of persisters and suggest new ideas for choosing strategies for more effective treatmentofpersistent infections.
