Clinical Outcomes of Conduction System Pacing vs Right Ventricular Septal Pacing in Atrioventricular Block
Key result
Conduction system pacing was superior to right ventricular septal pacing in reducing the composite of PICM, CRT upgrade, HFH, and mortality (HR 0.35; 95% CI 0.19-0.64; P<0.001).
Journal of the American College of Cardiology published a graphical abstract
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Why the study?
Patients with AV block receiving RV pacing risk pacing-induced cardiomyopathy, CRT upgrade, heart failure hospitalization, and mortality, but whether conduction system pacing mitigates these adverse outcomes compared to RV septal pacing needed evaluation.
Does conduction system pacing reduce the composite of pacing-induced cardiomyopathy, CRT upgrade, heart failure hospitalization, and mortality in patients with AV block compared to right ventricular septal pacing?
Key Points
- Compare the clinical outcomes of conduction system pacing (CSP) versus right ventricular septal pacing (RVsP) in patients requiring pacing for atrioventricular block.
- Randomized controlled trial (N=202; ACTRN12619001613190) allocating consecutive patients with atrioventricular block 1:1 to either RVsP or CSP, with a mean follow-up period of 25.2 ± 11.8 months.
- Assessed a primary composite endpoint of pacing-induced cardiomyopathy (PICM), upgrade to biventricular cardiac resynchronization therapy (CRT), heart failure hospitalization, and all-cause mortality.
- CSP significantly reduced the primary composite endpoint compared to RVsP (7.17 vs 20.69 events per 100 person-years; HR: 0.35; 95% CI: 0.19-0.64; P < 0.001).
- Reductions were driven by lower rates of PICM (4.58 vs 14.69 events per 100 person-years; HR: 0.31; 95% CI: 0.15-0.67; P = 0.002) and CRT upgrades (0 vs 1.92 events per 100 person-years; HR: 1.65e-9; 95% CI: 0-∞; P = 0.043), though lead revisions were higher with CSP (7.9% vs 1.0%; P = 0.017).
Study Design
Type
RCT (n=202)
Randomization
1:1
Structured PICO
Does conduction system pacing reduce the composite of pacing-induced cardiomyopathy, CRT upgrade, heart failure hospitalization, and mortality in patients with AV block compared to right ventricular septal pacing?
P
Population
202 patients with pacing indication for AV block without CRT indication, followed for a mean of 25.2 months.
I
Intervention
Conduction system pacing (CSP)
C
Comparator
Right ventricular septal pacing (RVsP)
O
Outcome
Composite endpoint of pacing-induced cardiomyopathy (PICM), upgrade to biventricular CRT, heart failure hospitalization (HFH), and all-cause mortalitycomposite
Main Result
Hazard Ratio: 0.35 (95% CI 0.19–0.64)
Absolute Event Rate: 7.17% vs 20.69%
p-value: p=< 0.001
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Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“An upcoming star in cardiology, who conducted the world's first randomised controlled trial in a new type of physiological pacing. Northern Health leads the way in this relatively new type of pacemaker procedure.”
“If we put everything together, it may not move the needle significantly. Larger studies powered to show reductions in heart failure likely are needed to support class 1 guideline recommendations.”
CLChee Loong (Dominic) ChowElectrophysiologist, Northern Health / University of Melbourne
“There has been a lack of randomized controlled data to recommend conduction-system pacing as an up-front pacing technique over traditional pacemakers. I hope that by presenting this randomized controlled data, working groups around the world can perhaps review the guideline recommendation and if the data is sufficient, upgrade it.”
Implication
Conduction system pacing significantly reduces adverse clinical outcomes, primarily pacing-induced cardiomyopathy and need for CRT upgrade, compared to right ventricular septal pacing in patients with AV block.
Abstract
BACKGROUND Patients with atrioventricular (AV) block receiving right ventricular (RV) pacing are at risk of pacing-induced cardiomyopathy (PICM), need for upgrade to biventricular cardiac resynchronization therapy (CRT), heart failure hospitalization (HFH), and mortality. Conduction system pacing (CSP) is a promising pacing strategy to mitigate these adverse outcomes. OBJECTIVES The aim of this study was to compare the clinical outcomes between RV septal pacing (RVsP) and CSP. METHODS A randomized controlled trial (RCT) was performed in 202 consecutive patients with pacing indication for AV block without CRT indication, with a 1:1 randomization allocation ratio between RVsP and CSP. The primary outcome was a composite endpoint of PICM, upgrade to biventricular CRT, HFH, and all-cause mortality. This trial was registered with the Australian New Zealand Clinical Trials Registry. RESULTS CSP was successful in 89 of 101 patients (88.1%). After a mean follow-up period of 25.2 ± 11.8 months, CSP was associated with lower composite endpoint (7.17 vs 20.69 events per 100 person-years; HR: 0.35; 95% CI: 0.19-0.64; P < 0.001) primarily driven by lower PICM (CSP 4.58 vs RVsP 14.69 events per 100-person-years; HR: 0.31; 95% CI: 0.15-0.67; P = 0.002) and need for CRT upgrade (0 vs 1.92 events per 100-person-years; HR: 1.65e-9; 95% CI: 0-∞; P = 0.043). There was no difference in HFH (CSP 0.48 vs RVsP 2.92 events per 100-person years; HR: 0.16; 95% CI: 0.02-1.37, P = 0.057) or all-cause mortality (CSP 2.86 vs RVsP 4.72 events per 100-person-years; HR: 0.61; 95% CI: 0.22-1.69; P = 0.337). Lead revision occurred more with CSP (8 patients [7.9%] vs 1 patient [1.0%]; P = 0.017). CONCLUSIONS This RCT demonstrates the superiority of CSP over RVsP in achieving improved clinical outcomes and supports the indication of CSP as an upfront pacing technique for patients with AV block. (CSPACE: A Randomised Controlled Trial Comparing Right Ventricular Pacing with Conduction System Pacing; ACTRN12619001613190).
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Cite This Study
Chow et al. (2025) conducted an RCT in Atrioventricular (AV) block (n=202). Conduction system pacing (CSP) vs. Right ventricular septal pacing (RVsP) was evaluated on Composite of pacing-induced cardiomyopathy (PICM), upgrade to biventricular CRT, heart failure hospitalization (HFH), and all-cause mortality (HR 0.35, 95% CI 0.19-0.64, p=< 0.001). Conduction system pacing was superior to right ventricular septal pacing in reducing the composite of PICM, CRT upgrade, HFH, and mortality (HR 0.35; 95% CI 0.19-0.64; P<0.001).