Conduction system pacing (CSP) is superior compared with right ventricular septal pacing (RVsP) in achieving improved clinical outcomes in patients with atrioventricular (AV) block, according to the CSPACE study published Aug. 18 in JACC. These findings support the broadening of the indication of CSP as an upfront pacing technique for patients with AV block.

Conduction system pacing (CSP) is superior compared with right ventricular septal pacing (RVsP) in achieving improved clinical outcomes in patients with atrioventricular (AV) block, according to the CSPACE study published Aug. 18 in JACC. These findings support the broadening of the indication of CSP as an upfront pacing technique for patients with AV block.

Chee Loong (Dominic) Chow, MBBS, et al., randomized 202 patients with a pacing indication for AV block without an indication for cardiac resynchronization therapy (CRT) to either CSP or RVsP. The patients were recruited between June 1, 2020, and March 13, 2024 from two metropolitan hospitals in Melbourne, Australia.

The primary outcome was a composite of pacing-induced cardiomyopathy (PICM), upgrade to biventricular CRT, heart failure hospitalization (HFH) and all-cause mortality. Follow-up occurred at three, six and 12 months, and then every six months.

Results showed that CSP was successful in 89 of 101 patients (88%). After a mean follow-up of 25 months, the primary endpoint was lower with CSP than RVsP (7 vs. 21 events per 100 person-years; HR, 0.35; p<0.001), primarily driven by less need for CRT upgrade (0 vs. 2 events per 100 person-years; HR, 1.65e9; p=0.043) and PICM (5 vs. 15 events per 100 person-years; HR, 0.31; p=0.002). No between-group difference was observed for all-cause mortality or HFH.

Of note, lead revision occurred more frequently with CSP than RVsP (8 patients vs.one patient; p=0.017).

“In patients with AV block, CSP resulted in a lower incidence of PICM and need for biventricular CRT upgrade, at the expense of higher requirement for lead revision, compared with RVs,” write the authors. “…This [randomized controlled trial] supports the broadening of the indication of CSP as an upfront pacing technique for pacemaker implantation in patients with AV block.”

“The CSPACE study adds to the body of evidence supporting physiological pacing in patients with AV block,” write Ratika Parkash, MD, MS, and Kenneth A. Ellenbogen, MD, FACC, in an accompanying editorial comment. “CSP offers significant advantages over conventional CRT, as there are fewer leads, longer battery life and possibly superior outcomes.”