Arrhythmias & electrophysiologyCohort study
Transseptal activation delta: A novel electrocardiographic criterion for left bundle branch capture
- prospective, observational, single-center study
- consecutive patients
- separate prospective validation cohort
Authors' conclusion
TAD is a practical, reproducible intraoperative criterion for identifying left bundle branch capture. A 25-ms threshold supports the role of TAD as a confirmatory marker of conduction system capture with high specificity.
Study context
- Population
- Patients who underwent left bundle branch pacingn = 122 consecutive patients, 142 pacing observations (in 20 patients, measurements during septal pacing and after confirmation of left bundle branch capture), separate prospective validation cohort of 30 additional patients
- Exposure
- Transseptal activation delta (TAD) against left bundle branch capture defined by electrocardiographic criteria and dynamic pacing maneuvers
Main finding
As reported in the abstract
Diagnostic accuracy of TAD threshold of ≥25 ms for left bundle branch capture
| Group | sensitivity | specificity | overall diagnostic accuracy |
|---|---|---|---|
| transseptal activation delta (TAD) | 78.9% | 95.7% | 84.5% |
Observational data: associations, not effects.
Further findings
Diagnostic performance in the prospective validation cohort
- this threshold retained diagnostic performance
Original publication
Transseptal activation delta: A novel electrocardiographic criterion for left bundle branch capture. Heart Rhythm. Published 25 May 2026. doi:10.1016/j.hrthm.2026.05.033
Summarised from the published abstract; every number is checked against it