Impact of Pacing Positions on Dyssynchrony: Insights from Virtual Body Surface Mapping

BackgroundRight ventricular (RV) endocardial pacing is a standard therapy for bradycardia, but it can lead to left ventricular (LV) dysfunction due to electrical dyssynchrony. While conduction system pacing has emerged as a promising alternative, traditional RV pacing remains common, making the optimization of RV lead position clinically relevant. This study aimed to determine whether dyssynchrony metrics derived from a new four-electrode virtual body surface mapping (VBSM) system could be used to identify optimal pacing sites. MethodsWe retrospectively analyzed data from 65 patients with RV pacemakers or ICDs. Using imaging from electronic medical records (EMRs), RV lead positions were mapped to 11 of 18 defined anatomical segments. We obtained measurements for three dyssynchrony parameters (standard deviation of activation times [SDAT], QRS duration [QRSd], and QRSarea) from a VBSM system. A point-biserial correlation was used to evaluate the relationship between these parameters and lead position. ResultsSeptal positions consistently demonstrated lower SDAT values compared to free wall positions (mean SDAT of 23.64 ms vs. 34.03 ms). SDAT showed a strong positive correlation with non-septal positions (rpb = 0.67, p<0.01), indicating that higher SDAT values are strongly associated with free wall pacing. This association was less marked for QRSd and absent for QRSarea. Our findings showed a weak correlation between dyssynchrony parameter rankings and the hemodynamic performance rankings reported in external literature. ConclusionSDAT is a valuable parameter for distinguishing between septal and non-septal right ventricular pacing positions. These findings underscore the potential of VBSM as a non-invasive tool for guiding electrode placement to minimize electrical dyssynchrony and potentially optimize hemodynamic outcomes. However, the retrospective nature of the study, small sample size, and reliance on literature-derived hemodynamic data are key limitations. Future direct hemodynamic studies are essential to validate these observations.