The Resynchronization Effect in Left Bundle Branch Pacing can be Evaluated Non-invasively with the Implementation of Lead V8
Bibliographic record
Abstract
Abstract Background Left bundle branch area pacing (LBBAP) is increasingly being used for cardiac resynchronization therapy (CRT); however an additional left ventricular (LV) lead is required when resynchronization remains incomplete. This study evaluates whether lead V8 can provide a simple, non-invasive marker of persistent posterolateral LV delay during LBBAP. Methods Consecutive patients undergoing LOT-CRT implantation were included. Standard 12-lead ECGs were obtained with the V5 electrode repositioned to the V8 location. Local activation time was measured as the steepest negative downslope of the QRS (negative derivative activation time, NDAT) and compared with the LV electrical delay (LVED) determined from the LV lead during LBBAP. Results Thirty consecutive patients undergoing LOT-CRT implantation were included with a total of 106 ECG recordings with corresponding LVED measurements. The NDAT-V8 demonstrated a strong correlation with the LVED during intrinsic conduction (r = 0.95) and during all LBB pacing subtypes: combined r = 0.922; mean difference 2.5 ± 8 ms; RV septal pacing, r = 0.89; LV septal pacing, r = 0.92; non-selective LBBP, r = 0.91; and selective LBBP, r = 0.81. The correlation of LVED during intrinsic conduction and all LBBAP pacing subtypes was significantly weaker for NDAT-V6 and the RWPT in V6 and V8 (r=0.681, 0.626 and 0.726, respectively). Conclusion The NDAT-V8 provides a reliable non-invasive surrogate for the LV posterolateral wall delay during LBBAP, outperforming NDAT-V6 and the RWPT in V6 and V8 and establishes the groundwork for future studies evaluating NDAT-V8 as a tool to guide adequate resynchronization during LBBAP. Clinical Perspective What is Known - Although left bundle branch area pacing (LBBAP) is increasingly being used as an alternative resynchronization strategy, complete resynchronization is not always achieved. - The negative derivative activation time in lead V8 (NDAT-V8) has been shown to provide a non-invasive marker of the left ventricular electrical delay– also referred to as QLV - at the LV postero-lateral wall in patients with left bundle branch block, intraventricular conduction delay, and right bundle branch block. What the Study Adds - This study shows that the NDAT-V8 provides a non-invasive surrogate for the left ventricular posterolateral wall delay during LBBAP. - This study establishes the groundwork for future studies evaluating NDAT-V8 as a tool to guide adequate resynchronization therapy during LBBAP to determine when the addition of a coronary sinus lead is needed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".