Study On Electrocardiogram, Imaging And Methodology In Left Bundle Branch (regional) Pacin

PartⅠQuantitative Distance and Electrocardiographic Parameters for Lead-implanted Site Selection to Enhance the Success likehood of Left Bundle Branch PacingBackground:Left bundle branch pacing(LBBP)is a novel near-physiological pacing method that still lacks quantitative criteria to guide the selection of lead-implanted sites to enhance the success likelihood of lead deployments.Ojective:This study aimed to quantitatively analyze the relationships of LBBP success likelihood to the distribution of lead-implanted sites and the lead-localization-pacing electrocardiographic(ECG)features.Methods:All the lead-implanted sites in patients with finally successful LBBP were enrolled for analysis,including successful and failed sites.A novel coordinate system was invented to describe the sites’distribution as longitudinal distance(longit-dist)and lateral distance(lat-dist).Corrected distance parameters were generated to eliminate the cardiac dimension variations.The lead-localization-pacing ECG parameters were also collected,such as paced QRS duration(locat-QRSd),left ventricular activation time(locat-LVAT),LVAT/QRSd ratio(locat-LVAT/QRSd),and QRS directions.Results:A total of 94 patients with 105 successful sites and 93 failed sites were enrolled.Longit-dist and corrected longit-dist of successful sites were significantly longer,while locat-QRSd and locat-LVAT were shorter and locat-LVAT/QRSd was lower than failed sites.There was a positive dose-response relationship between LBBP success likelihood and corrected longit-dist with a cut-off of 26.95mm,whereas there were negative dose-response relationships of LBBP success likelihood to locat-QRSd,locat-LVAT,and locat-LVAT/QRSd with the cut-offs of 142ms,92ms,and 64.7%,respectively.Downward QRS direction in Ⅱ/Ⅲ ECG leads was also associated with successful LBBP.Conclusions:Longit-dist,locat-QRSd,locat-LVAT,and locat-LVAT/QRSd were quantitative parameters to guide the selection of lead-implanted sites during LBBP implantation.PartⅡPacing Features and Factors Influencing Success Likelihood and QRS Shortening in Bilateral Bundle Branch Area PacingBackground:Left bundle branch pacing(LBBP)maintains left ventricular synchrony but induces right ventricular conduction delay(RVCD).Anodal-ring capture(ARC)was observed to improve RVCD,but the understanding of this phenomenon is limited.Objective:This study aimed to analyze the electrical features and influencing factors of ARC in LBBP.Methods:Patients receiving LBBP with intraoperative ARC testing were retrospectively enrolled.Electrocardiographic(ECG)parameters,like stimulus-to-QRS duration(stim-QRSd),stimulus-to-left/right ventricular activation time(stim-LVAT/RVAT),and RV-LVAT interval,were measured.A novel coordinate system was applied to describe the lead-implanted sites,including the corrected longitudinal(longit-dist)and corrected lateral distance(lat-dist).Intergroup comparisons,correlation analysis,and stepwise logistic regression were performed.Results:Totally 105 patients with ECG and fluoroscopic data were included,among which 65(62%)patients achieved ARC at a pacing output ≤5.0 V/0.5ms(average 3.1 V/0.5ms).ARC further shortened the stim-QRSd(Δstim-QRSd=-13.1±7.5 ms,P<0.0001)on the basis of LBBP.Better unipolar-ring threshold and R-wave sensing in LBBP-ARC group indicating the critical role of ring-septum contact in ARC.Longer corrected longit-dist and shorter corrected lat-dist were positively correlated with the success likelihood of ARC,likely due to the greater relative angle of lead while entering the septum,which leads to the greater intra-septal lead length and better ring-septum contact.Shorter stim-LVAT and longer stim-QRSd during LBBP correlated with greater QRS shortening after ARC,which actually depended on the prolonged RV-LVAT interval.Conclusions:This study identified an area closer to the anterior-middle septum with higher success likelihood of ARC in LBBP.ARC could further shorten QRSd especially in patients with greater interventricular electrical dyssynchrony during LBBP.PartⅢComparison Between Solia S60 Lead+Selectra 3D Sheath and 3830 Lead+C315 His Sheath in Achieving Left Bundle Branch Area PacingBackground:To promote wider adoption and avoid monopolies,more options for left bundle branch area pacing(LBBAP)are needed.Medtronic Inc.’s 3830 lead and C315 sheaths are currently the most commonly used and have been proven safe and effective.Biotronik Inc.has also developed their own LBBAP instruments,like Solia S leads and Selectra 3D sheaths,but they are still in the early stages with limited experience.Aim:This study aimed to compare the procedure characteristics,pacing performance,and lead-implanted site distribution between these two instruments.Methods:Patients received LBBAP implantation by Solia S60 lead and Selectra 3D sheath were consecutively enrolled,as well as patients using 3830 lead and C315 HIS sheath in the same period.Patients with successful procedures were identified and the success rate was calculated.The propensity score matching(PSM)was used to select comparable patients with 3830 lead as the control group.Then,procedure characteristics,pacing performance,and imaging features were compared.Complications were documented,such as pneumothorax,hemothorax,cardiac perforation,ventricular septal perforation,septal vascular injury,and lead dislodgement.Results:Totally 27 and 78 patients received LBBAP implantation with Solia S60 lead and 3830 lead in the enrollment period,among which 22(81.5%)and 67(85.9%)patients successfully achieved LBBAP,respectively.The success rates had no significant difference.No significant differences were found between two groups in site success rate,proportion of one-time success,LBB potential record,LBB capture,time consumption of LBBAP lead implantation,radiation time,pacing parameters,paced QRS duration,left ventricular activation time,and distribution of lead-implanted sites.The incidences of complications were low in both groups,but two patients occurred lead dislodgement due to helix rollback and coronary vein injury in Solia group,requiring clinical concern.Conclusions:Solia S60 lead with Selectra 3D sheath is feasible in achieving LBBAP.It had similar success rate and pacing performance to 3830 lead and C315 HIS sheath.However,further study is required to analyze the risk of vascular injury.