Application Of Echocardiography In Functional Evaluation Of Left Bundle Branch Pacing And Guide Of Lead Implantatio

(Part I)Echocardiographic assessment of the effects of left bundle branch area pacing and right ventricular septal pacing on cardiac structure and functionObjectiveThis study aimed to observe the effect of left bundle branch area pacing(LBBAP)on cardiac structures and functions compared with that of right ventricular septal pacing(RVSP)by echocardiography to provide more evidence for clinical decision of the pacemaker implantation surgery.MethodsNinety-five patients scheduled for dual-chamber pacemaker implantation from November 2020 to April 2022 were enrolled consecutively and divided into LBBAP group(n=50)and RVSP group(n=45)according to the different pacing sites.Routine echocardiography was performed before and six months after operation.To evaluate the changes in cardiac structure and function the main parameters were as follows.Left atrial diameter,left ventricular internal dimension diastole,left ventricular internal dimension systole,left ventricular end-diastolic volume,left ventricular end-systolic volume,left ventricular fractional shortening,and left ventricular ejection fraction were measured for the assessment of the left heart.Septal-to-posterior wall motion delay and interventricular mechanical delay(IVMD)were used to evaluate interventricular synchronicity.For the assessment of the right ventricle(RV),RV base diameter,RV mid diameter,RV length,tricuspid annular plane systolic excursion(TAPSE)and right ventricular fractional area change were measured.Comparison was made between and within groups.ResultThere was no significant difference in the indexes between the two groups before operation(P>0.05).Six months after the operation,the IVMD of LBBAP group was significantly reduced than that before operation(P=0.03),and the IVMD of RVSP group was also significantly lower than that of RVSP group(P=0.01).Six months after surgery,TAPSE in RVSP group was significantly reduced than that in preoperative baseline data(P<0.01).ConclusionLBBAP can protect the interventricular synchronicity compared with RVSP.And RVSP may do harm to the systolic function of the right ventricle to some degree.(Part Ⅱ)Assessment of ventricular function and synchronicity after left bundle branch pacing compared with right ventricular septal pacing using realtime 3D-echo combined with speckle tracking echocardiographyObjectiveTo assess the changes of the ventricular function and synchronicity after left bundle branch pacing(LBBAP)compared with right ventricular septal pacing(RVSP)by realtime 3Decho combined with speckle tracking echocardiography.MethodsNinety-five patients scheduled for dual-chamber pacemaker implantation from November 2020 to April 2022 were enrolled consecutively and divided into LBBAP group(n=50)and RVSP group(n=45)according to the different pacing sites.Echocardiographic measurements were recorded before operation and the sixth month after surgery.The longitudinal strain of left ventricle was evaluated by stratified strain technique,and the main indexes included global longitudinal strain of endocardial myocardium(GLS-endo),global longitudinal strain of mid myocardium(GLS-mid),global longitudinal strain of epicardial myocardium(GLS-epi)and peak strain dispersion(PSD).PSD was used to evaluate the left ventricular synchronicity.The volume and function of the left ventricle were evaluated by Dynamic Heart Model(DHM),and the main indexes included left ventricular end-diastolic volume,left ventricular end-systolic volume,and left ventricular ejection fraction.The volume,function and strain of right ventricle were analyzed by 3D auto RV,the indicators including right ventricular end-diastolic volume(RVEDV),right ventricular end-systolic volume(RVESV),right ventricular ejection fraction(RVEF),right ventricular fractional area change(RVFAC),right ventricular septum longitudinal strain(Sep-RVLS)and right ventricular free wall longitudinal strain(FW-RVLS).Echocardiographic data were obtained preoperatively and six months after operation.The data then were analyzed and compared between and within groups to evaluate the effects of the ventricular function and synchronicity.ResultsThe PSD of both groups six months after the operation were significantly reduced compared with the PSD before operation(P<0.05).And six months after the operation,the PSD of LBBAP group was significantly lower than that of the RVSP group(P=0.03).Six months after the operation,the GLS-endo of the LBBAP group was significantly higher than that of the RVSP group(P=0.04),suggesting that LBBAP was more conducive to improve left ventricular synchronicity and function.Six months after the surgery,RVEDV in the RVSP group significantly increased compared with that before surgery(P=0.029).RVEF,Sep-RVLS and FW-RVLS of RVSP group were significantly decreased at the sixth month postoperatively compared with those before operation(P<0.05),suggesting that the right ventricular function in RVSP group decreased compared with that before surgery.These results suggested that RVSP had some effect on right ventricular function after operation,while LBBAP had no significant effect and had higher safety.ConclusionRealtime 3D echocardiography combined with speckle tracking technique was a reliable way to evaluate early ventricular function and synchronicity after LBBAP and RVSP.Compared with RVSP,LBBAP showed better ventricular mechanical synchronicity and preserved right ventricular function.(Part Ⅲ)Exploration of left bundle branch pacemaker implantation guided by transthoracic echocardiography combined with X-rayObjectiveTo investigate the application of transthoracic echocardiography(TTE)combined with Xray guiding pacemaker implantation in the left bundle branch area(LBBAP).MethodsFifteen patients scheduled for LBBAP implantation were consecutively enrolled from May to November 2022.TTE combined with X-ray guidance was used to complete the pacemaker implantation surgery.The operations were mainly ultrasound-guided and confirmed by X-ray if necessary.Ultrasound guidance mainly includes real-time monitoring of the course of pacing lead,lead positioning,depth of lead screwing into the interventricular septum and testing the safety and effectiveness of the procedure.TTE was performed preoperatively and three months postoperatively.ResultsPacemaker implantation was successfully completed in fifteen patients,the left bundle branch was successfully paced without surgical complications,including twelve cases of dual-chamber pacemaker DDD and three cases of single-chamber pacemaker VVI.Postoperative programming data were good.For these fifteen patients,who underwent TTE combined with X-ray-guided LBBAP lead implantation,the average procedure time was 9.1 minutes,and the mean fluoroscopy time was 2.4 minutes.The LBBAP lead position was 30.0 ± 5.0 mm from the tricuspid annulus,and the depth of the lead into the interventricular septum was 10.4± 1.6mm.The follow-up results at the third month after surgery showed that the anteroposterior diameter of left ventricular end diastole was significantly reduced compared with the baseline data before operation(P=0.001),showing good safety and efficacy.ConclusionTTE combined with X-ray guided pacemaker implantation in the left bundle branch area can shorten the X-ray exposure time,reduce the ionizing radiation damage,observe the course of the lead,precisely locate the pacing lead,reduce complications,and add to the safety and efficacy of surgery.