NEW Conduction System Pacing (CSP) Lead Exceeds Primary Safety End Points in the NEW ASCEND CSP IDE Study1
Abbott Cardiac Rythm Management | April 25, 2026
Left bundle branch area pacing (LBBAP) is an established conduction system pacing (CSP) strategy, but current practice often relies on adapting leads not designed for conduction system engagement.
A prospective, multicenter, global, single-arm study evaluated the safety and effectiveness of Abbott’s new CSP ICD lead in patients indicated for an Implantable Cardioverter Defibrillator (ICD) or a Cardiac Resynchronization Therapy Defibrillator (CRT-D). The primary safety endpoint was freedom from lead-related serious adverse events and a composite of acceptable pacing capture threshold and adequate R-wave sensing at 3 months, with defibrillation testing assessed in a prespecified cohort.
Among 205 implant attempts, lead implantation was successful in 98.5% of patients. LBBAP criteria were met in 99.0%, with confirmed or likely left bundle branch capture achieved in 86.0%. The 3-month major complication-free rate was 97.5%, exceeding the safety performance goal. The primary effectiveness endpoint was achieved in 94.6%, also surpassing the prespecified benchmark.
The defibrillation threshold (DFT) testing was successfully completed in 120 patients without lead repositioning.
DFT testing results
yielded a success rate of
100%
Of these 120 patients,
92.5% were
successfully defibrillated
with a single 20 J shock
Lead electrical performance remained stable through 3 months.
These results demonstrate high implant success, consistent conduction system engagement, and favorable short-term safety and electrical performance with a dedicated CSP ICD lead. The findings support the feasibility of purpose-built lead design for LBBAP, although longer-term follow-up is needed to assess durability and clinical outcomes.
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1. Schaller, R. D., Sanders, P., Joza, J. E., Zimetbaum, P. J., Birgersdotter-Green, U. M., Tung, R., ... & Burri, H. LB-525395-03 SAFETY AND EFFICACY OF A NOVEL ICD LEAD FOR LEFT BUNDLE BRANCH AREA PACING: RESULTS FROM THE ASCEND CSP TRIAL. Heart Rhythm. [Data obtained from submitted manuscript]
