Study On The Feasibility Of Three-Dimensional Electroanatomical Mapping To Guide Cardiac Resynchronization Therapy

Objectives:Heart failure is the end stage of various cardiac diseases,and complete left bundle branch block is prevalent in up to 20%of patients with heart failure requiring hospitalization.Complete left bundle branch block can lead to severe cardiac desynchronization,causing further deterioration of the patient’s cardiac function.In about 30%of patients,the ECG shows complete left bundle branch block,but the left bundle branch conduction is normal,which is called false-complete left bundle branch block.Three-dimensional electroanatomical mapping can visualize cardiac anatomy and potentials.Therefore,we propose that three-dimensional electroanatomical mapping can assess the true status of left bundle branch conduction and thus guide the selection of CRT left ventricular lead implantation sites.The aim of this study was to investigate the feasibility of three-dimensional electroanatomical mapping in the selection of left ventricular lead implantation sites for cardiac resynchronization therapy by performing three-dimensional electroanatomical mapping in patients with complete left bundle branch block manifestations who met the AHA2009 CLBBB criteria on the electrocardiogram.Methods:A total of 25 patients with heart failure meeting the AHA 2009CLBBB criteria and the ESC 2016 CRT Class Ia indication who were admitted to the First Affiliated Hospital of Kunming Medical University from September 2020 to December 2021 were enrolled.All patients sign the informed consent notification.Before implantation of the CRT system,a retrograde aortic pathway is used to place lead on the endocardial surface of the left ventricle to construct an anatomical model of the left ventricle and define the sequence of left ventricular excitation.If an exact left bundle branch potential is mapped intraoperatively in the left bundle branch area,confirming normal left bundle branch conduction,false-left bundle branch block is considered,and lateral venous pacing is performed.If the exact left bundle branch potential is not mapped,the left bundle branch potential is behind the local potential or hidden in the local potential,and electrical or mechanical stimulation of the left bundle branch area shows narrowing of the QRS wave and the left bundle branch potential is ahead of the local potential,confirming a true complete left bundle branch block or slow left bundle branch conduction,then left bundle branch pacing is performed.Preoperative electrocardiograms were collected from all enrolled patients.Based on the true conduction of the left bundle branch recorded by intraoperative three-dimensional electroanatomical mapping,we evaluated the compliance of the ECG with the ESC 2021 CLBBB diagnostic criteria and Strauss criteria in the enrolled patients.The sensitivity,specificity,and agreement rate of each diagnostic criteria were also calculated separately.In this study,severe infection of the femoral artery puncture site,femoral arteriovenous fistula requiring surgery,femoral artery dissection,pacemaker pocket rupture or infection,cardiac tamponade,ventricular septal defect,pacemaker lead fracture,pneumothorax,hemothorax,acute coronary syndrome,and acute left heart failure were defined as serious complications.Record the occurrence and management of complications intraoperatively and 7 days,3 months,6 months,9 months,12 months after surgery.All enrolled patients were collected preoperatively,6 months postoperatively,and12 months postoperatively for 12-lead ECG,echocardiography routine and synchronization index,and the patients’pacemaker parameters,postoperative complication occurrence and management were recorded.SPSS 27.0 statistical software was used to analyze the data in this study,and differences were judged as statistically significant at P<0.05.Results:1.In this study,25 patients with complete left bundle branch block on the ECG were measured by three-dimensional electroanatomical mapping.16 patients with true-complete left bundle branch block（11 patients with left bundle branch block and 5 patients with slow left bundle branch conduction）were paced with three-chamber left bundle branch pacing;9 patients with normal left bundle branch conduction were false-left bundle branch block and paced with three-chamber lateral vein pacing.The average follow-up time in this study was 13.2±3.35 months.2.By analyzing the preoperative ECG of 25 patients,this study found that the ESC2021 diagnostic criteria for CLBBB had a sensitivity of 37.5%,a specificity of 88.9%,and an agreement rate of 56%.The Strauss criteria for CLBBB had a sensitivity of87.5%,a specificity of 77.8%,and an agreement rate of 84%.3.In the left bundle branch and lateral vein pacing groups,the pacemaker parameters were programmed intraoperatively,6 months postoperatively,and 12months postoperatively,and there were no statistical differences in sensing,threshold and impedance of left ventricular lead within the groups（P>0.05）.4.One serious complication occurred in this study,a pacemaker pocket infection,with an incidence of 4%.This patient developed a pacemaker infection 1 year after CRT implantation,and was readmitted to the hospital to remove the pacemaker pulse generator and leads,and the pacemaker was implanted in the contralateral anterior thoracic region after 7 days of anti-infection treatment with vancomycin,with no re-infection after surgery.5.In the left bundle branch pacing group,QRS wave duration was significantly shorter in the immediate postoperative period compared with the preoperative period[（121.75±14.64）ms vs（166.38±6.94）ms,P<0.001],QRS wave duration was significantly shorter at 12 months postoperatively compared with the immediate postoperative period[（108.50±11.16）ms vs（121.75±14.64）ms,P=0.003],QRS wave duration was significantly shorter at 12 months postoperatively compared with the preoperative period[（108.50±11.16）ms vs（166.38±6.94）ms,P<0.001].LVEF,LAD,LVEDD,AVVTI,IVMD,EA distance/RR duration,and Ts-SD₁₂ were significantly improved at 12 months postoperatively compared with preoperatively,with statistically significant differences（P<0.05）.6.In the lateral venous pacing group,QRS wave duration was significantly shorter in the immediate postoperative period compared with the preoperative period[（147.33±14.71）ms vs（175.11±16.11）ms,P=0.001],QRS wave duration was significantly shorter at 12 months postoperatively compared with the immediate postoperative period[（128.22±15.51）ms vs（147.33±14.71）ms,P=0.003],QRS wave duration was significantly shorter at 12 months postoperatively compared with the preoperative period[（128.22±15.51）ms vs（175.11±16.11）ms,P<0.001].LVEF,LAD,LVEDD,AVVTI,IVMD,IVMD,EA distance/RR duration,and Ts-SD₁₂were significantly improved at 12 months postoperatively compared with preoperatively,and the differences were statistically significant（P<0.05）.7.At immediate postoperative and 12-month postoperative follow-up,the QRS wave duration was shorter in the left bundle branch pacing group than in the lateral venous pacing group（P<0.05）.At the 12-month postoperative follow-up,there was no statistical difference between the left bundle branch pacing group and the lateral venous pacing group in terms of LAD,LVEDD,LVEF,IVMD,EA distance/RR duration,Ts-SD₁₂,and AVVTI（P>0.05）.In the left bundle branch pacing group and the lateral vein pacing group,the difference in improvement of the preoperative indexes at 12 months postoperatively,（35）LAD,（35）LVEDD,（35）LVEF,（35）IVMD,（35）EA distance/RR duration,（35）Ts-SD₁₂,（35）AVVTI,and（35）QRS wave duration were not statistically different（P>0.05）.Conclusions:1.Three-dimensional electroanatomical mapping can further accurately diagnose true-complete left bundle branch conduction block.2.Three-dimensional electroanatomical mapping to guide the choice of left ventricular lead implantation is safe and feasible.