Heart failure & cardiomyopathies
Cardiac Resynchronization Therapy Using a Conduction System Pacing Defibrillation Lead in Patients Meeting CRT-D Indications: Six-Month Clinical Outcomes Results From the ASCEND Conduction System Pacing (CSP) Study
Authors' conclusion
LOT-CRT with a dedicated CSP ICD lead achieved high implant success, preserved defibrillation efficacy, and had favorable safety, with greater left ventricular systolic function and clinical improvement than matched conventional CRT, supporting CSP-based CRT defibrillator therapy.
Study context
- Population
- Cardiac resynchronization therapy (CRT) defibrillator patients undergoing attempted implantation of a CSP implantable cardioverter-defibrillator (ICD) lead and a coronary sinus leadCRT defibrillator patients in the ASCEND CSP IDE study
- Participants
- 52 patients
- Exposure
- LOT-CRT vs propensity-matched conventional BiV-CRT
- LOT-CRTn = 52
- Outcome
- Implantation success
Methodological detailspropensity-matched comparison
- Propensity-matched comparison
Main finding
As reported in the abstract
LOT-CRT
98.1%
51 of 52 of 52
- Left bundle branch area pacing (LBBAP) capture
- 51 of 51
Observational data: associations, not effects.
Further findings
Lead-related events
CRT responders (≥5%)
Super-responders (≥14.5%)
Improved by clinical composite score
| Outcome | LOT-CRT | BiV-CRT | |
|---|---|---|---|
| Freedom from CSP lead-related serious adverse device effects · 6 months | 98.1% (95% CI 87.1%–99.7%) | Not reported in the abstract | BiV-CRT: not reported in the abstract |
| Defibrillation successAll tested patients | 100% | Not reported in the abstract | BiV-CRT: not reported in the abstract |
| LVEF increase | 10.4 points | 4.6 points |
- Lead-related events: P = 1.0
- Left ventricular ejection fraction (LVEF) increase: P = 0.0005
- CRT responders (≥5%): P = 0.0107
- Super-responders (≥14.5%): P < 0.0001
- Improved by clinical composite score: P = 0.0016
Change from baseline (LOT-CRT)
- QRS narrowed by
- 30.4 ms
- LVEF increased by
- 10.4 points
- P (both)
- P < 0.0001
LOT-CRT by LBBB status (subgroup)
- Significant improvements in both LBBB and non-LBBB patients
Original publication
Cardiac Resynchronization Therapy Using a Conduction System Pacing Defibrillation Lead in Patients Meeting CRT-D Indications: Six-Month Clinical Outcomes Results From the ASCEND CSP Study. JACC Clin Electrophysiol. Published 22 October 2026. doi:10.
Summarised from the published abstract; every number is checked against it