Validation of left bundle branch pacing criteria: are we really doing it well?

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch (LBB) area pacing (LBBAP) has been widely adopted for an increasing number antibradycardia and CRT procedures worldwide. Two different types capture have described during LBBAP: left ventricular septal myocardial (LVSP) or direct LBB (LBBP). Nevertheless, electrocardiographic diagnosis LBBAP remains one the challenges modern conduction system because there is a big overlap between both morphologies. Among new ECG-based criteria, R wave peak time in lead V6 (V6-RWPT) V6-V1 interpeak interval seem to be most practical ones adopted. However, their performance never validated external population. Purpose We aim validate reported criteria V6-RWTP our Methods Single-center study involving all consecutive patients who received LBBAP. LBBP was defined according presence QRS morphology transition decremental pacing. The binary decision rules using sensitivity (SN) specificity (SP). V6-RWPT discriminating LVSP assessed receiver operating characteristic (ROC) curve. Results A total 188 with intended were screened. Successful achieved 174 (92.5%). Only 71 confirmed by included analyse interval. 75.7±9.6 ms tracings 94.4±10.1 LVS (p<0.001), 41.9±12.1 25.6±8.7 (p<0.001). average difference from 16.5±5.2 ms. ROC curves differential (Figure 1, which compares them those original articles) showed diagnostically optimal value differentiation 83 (SN 80.3% SP 91.1%). 100% cut-off 79.5 69.0%). For interval, 33.5 77.1% 84.6%). obtained >44 37.1%) 2). Conclusions Our comprises validation proposed capture. found nearly absolute concordance originally values. differed initially general cohort. Thus, consistent emerge as easily reproducible surrogates criteria.