The Effect Prediction And The Influence Of The Right Ventricular Lead Location On Ventricular Arrhythmias And Efficacy Of Cardiac Resynchronization Therapy

Objective:The purpose of this study was to investigate the prediction indicator of CRT response and the influence of different locations of right ventricular lead on efficacy and incidence rate of Ventricular arrhythmias in cardiac resynchronization therapy(CRT)and the risk of appropriate defibrillation.Methods: A total of 352 patients with chronic heart failure,hospitalized in the Anhui Provincial Hospital from May 2012 to July 2016,were recruited in this study.All of the patients received the treatments of cardiac resynchronization therapy and implantable cardioverter defibrillator(CRT-D).The level of serum N-terminal pro-brain natriuretic peptide(NT pro-BNP),left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume((LVESV)and left ventricular ejection fraction(LVEF)examined and improvement of QRS wave interval and NYHA grade were compared in the all patients before operation and 12 months after operation.The patients were divided into two groups,groups response(improvement rate of LVEF over 10%)and nonresponse(improvement rate of LVEF below 10%)based on the reactivity of the patients to CRT-D).Statistical analyses were used to evaluate the predictive effect of CRT-D in the involved patients.Subsequently,the patients were redivided into groups RVMS and RVA,according to the positioning of right ventricular lead so as to evaluate the therapeutic effects of the different locations of right ventricular conductor on CRT-D after 12 months of treatments.The subjects were continuously followed up for 24 months;clinical data and the data of pacemaker were collected and analyzed.The therapeutic effect of right ventricular lead locations on the incidence rate of ventricular arrhythmias and the risk of appropriate defibrillation were assessed by Kaplan-Meier curve and COX Multi-factors analysis.Results: 1)All of the patients in the two groups did not show any significant difference in the UCG examination and the data of cardiac function examination.After 12 months of pacemaker implantation,however,221 patients(62.8%)had response to CRT-D,showing an improvement of LVEF when examined UCG whereas 131 patients(37.2%)had nonresponse.The patients with response to CRT-D exhibited a remarkable improvement of cardiac function in LVEF when compared with those with nonresponse.Additionally,patients with response,but not those with nonresponse to CRT-D,showed an significant decrease of serum NT-proBNP after 12 months of operation while no difference of these indicators were noted in the patients before CRT-D administration.The results indicated that patients' response to CRT-D is closely associated with the improvement of heart function.2)No statistically significant difference of cardiac function as well as echocardiographic values was seen between groups RVMS and RVA before operation.RVMS and RVA patients had the response rates of 62.6% and 62.9%,respectively,and no remarked difference was noted after 12 months of operation.Cardiac function and structure as well as clinical manifestations were notably ameliorated but no difference was found of LVEF(7.8±4.32% vs.8.01±4.13%,P=0.74);LVEDV(18.33±11.29 vs.19.07±10.39,P=0.56);LVESV(34.9±23.5 vs.35.6±21.9,P=0.77)in the two groups.Similar deaths of were seen in patients of the two groups 12 months post operation.3)No significant effect of RVMS or RVA on VTAs incidence was noted if the location of left ventricular lead was not taken into consideration.By further adoption of sub-group analysis,however,we found that the incidence rate of VTAs in RVMS group was markedly higher than that of RVA group(31.5±10.2 % vs.48.7±11.5%,P=0.02)when the left ventricular lead was located at ALCV.In PLCV location,the risk of VTAs(HR=2.14,P=0.04)and appropriate defibrillation increased in group RVA,while a similar risks of VTAs(HR=1.28,P=0.50)and appropriate defibrillation(HR=1.53,P=0.33)was noted between groups RVMS and RVA if left ventricular lead was located at LCV.In addition,different LVC locations showed no impact on inappropriate defibrillation(P>0.05).Conclusions: 1)CRT/CRT-D is an effective strategy for the treatment of heart failure,and serum NT-proBNP concentration is helpful for prediction of the clinical treatment efficacy of CRT/CRT-D.2)RVMS seems not to be able to increase the therapeutic effect,improve clinical symptoms and signs and prognosis of CRT/CRT-D when compared with RVA.3)When the left ventricular lead is positioned at ALCV and PLCV,the location of right ventricular lead has a close correlation with the incidence rate of ventricular arrhythmias and the risk of appropriate defibrillation in CRT/CRT-D,suggesting that a certain distance between leads could not only improve cardiac function but reduce the risk of ventricular arrhythmias.