CSP vs BVP: Which one is better for HFrEF with non-LBBB?

In a meta-analysis comparing procedural and clinical outcomes between conduction system pacing (CSP) and biventricular cardiac resynchronization pacing (BVP), the former appears to outdo the latter for managing individuals with heart failure with reduced ejection fraction (HFrEF) without left bundle branch block (LBBB).

“This meta-analysis suggests that CSP may have better electrical synchrony and echocardiographic response compared with BVP in HFrEF patients with non-LBBB,” said the group of researchers from the National Heart Centre Singapore and Changi General Hospital, Singapore.

Compared with BVP, CSP led to significantly shorter implant-derived paced QRS duration (mean difference [MD], -19.7 ms, 95 percent confidence interval [CI], -36.2 to -3.3; p=0.0355) and greater improvement in left ventricular ejection fraction (LVEF; MD, 5.6 percent, 95 percent CI, 3.1–8 percent; p=0.0106).

However, there were no statistically significant differences in all-cause mortality (relative risk [RR], 0.53, 95 percent CI, 0.18–1.60; p=0.133) and HF hospitalization (HHF; RR, 0.54, 95 percent CI, 0.19–1.56; p=0.129) between CSP and BVP. [Medicina (Kaunas) 2025;doi:10.3390/medicina61071240]

The investigators noted that despite the shorter QRS duration and greater LVEF improvement with CSP, these did not translate to better clinical outcomes (reduced all-cause mortality or HHF), potentially due to the short follow-up durations in the trials included in the meta-analysis.

CSP may be a more physiologic alternative

“The role of BVP is less well-established in HFrEF patients without LBBB. CSP has gained significant traction and may provide a safe and more physiologic alternative to BVP in these patients,” the researchers noted.

CSP, which includes His-bundle pacing (HBP) and left bundle branch pacing (LBBP), is reportedly superior to BVP for shortening QRS duration and improving LVEF and New York Heart Association class. [Heart Rhythm 2024;21:881-889]

However, whether these benefits extend to non-LBBB patients remains uncertain, the researchers noted. “[T]he use of CSP in [non-LBBB] patients is only supported by a class 2B recommendation … in contemporary guidelines, and only when effective cardiac resynchronization therapy (CRT) cannot be achieved with BVP.”

The researchers conducted a meta-analysis that included three retrospective studies and one prospective trial. Of the 461 patients included (average age 75 years, 75 percent men), 255 underwent CSP while the rest had BVP.

One trial included patients with atrioventricular (AV) block, another included intraventricular conduction delay (IVCD), while the other two had a mix of patients with right BBB (RBBB), IVCD, AV block, and normal QRS.

With regard to CSP methods, two of the studies included a mix of HBP and LBBP, one used LBB optimized CRT, and the other one used a mix of all three methods. The average follow-up duration across all studies ranged between 365 and 810 days.

As only observational studies were included in the meta-analysis, the GRADE ratings for certainty of evidence ranged from low to very low, underpinning the need for further randomized studies. “[These] studies with longer follow-up may be required to elucidate potential benefits in clinical outcomes,” the investigators said.

“[F]uture studies focusing on specific types of non-LBBB (eg, RBBB, IVCD with and without concomitant AV block indication for pacing) would greatly clarify the distinction between these groups,” they added.