Noninvasive electrocardiographic imaging assessment of conduction system pacing device: a novel algorithm to assess intraventricular synchrony

Structured AbstractO_ST_ABSBackgroundC_ST_ABSLeft Bundle branch area pacing has become the procedure of choice for various indications including atrioventricular block and considered to be a physiologic modality of pacing compared to RV apex pacing. ObjectivesThe purpose of this study was to assess ventricular activation and synchrony in patients with LBBAP device using ECG imaging (ECGI). Methods25 consecutive patients underwent an LBBAP device implantation have been included in the study. ECG and ECGI analysis have been performed the day after implantation. Native and paced QRS, LVAT, RVAT and V1AD were calculated using ECG. TVACT, LVACT, LVACTi, RVACT, RVACTi and IVDS were calculated based on ECGI. All patients have been followed up for 12 months. ResultsAll patients were divided in 2 groups (wide and narrow QRS) based on intrinsic ECG and then based on paced ECG QRS. For initially narrow QRS group, activation time and synchrony during pacing was comparable to native. In wide QRS group these parameters were significantly improved. At paced rhythm analysis, classic ECG LBBAP parameters (paced QRS and LVAT) were not sufficient to properly evaluate the ventricular activation for paced rhythm. Discordance between ECG and ECGI analysys was identified in 25 patients. Two additional 12 lead ECG parameters predicting the ECGI measurements were found - V1AD and dRVAT. Follow up showed stable values of ejection fraction, paced QRS and pacing parameters. ConclusionsECG imaging can bring a significant value into assessing the efficacy of new pacing modalities and provide more data for precise determination of implantation outcomes, including detailed activation assessment and comparison to intrinsic conduction. Key ECGI values confirming proper ventricular activation have been defined and correlated with 12 lead ECG parameters to predict ventricle activation from ECG only.