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March 14, 2026European Heart Journal
Left bundle branch area vs biventricular pacing for cardiac resynchronization therapy: the LEFT-BUNDLE-CRT trial
Key result
Left-bundle branch area pacing was not shown to be non-inferior to biventricular pacing for positive CRT response at 6 months (89.7% vs 94.6%; RR 0.95; 95% CI 0.88-1.02).
Why the study?
Conduction system pacing has emerged as an alternative to biventricular pacing for CRT, but its non-inferiority in patients with typical LBBB was unknown.
Does left-bundle branch area pacing improve positive CRT response at 6-months compared to biventricular pacing in patients with guideline-based CRT indications and LBBB?
Study Design
Type
RCT (n=176)
Multicenter
Yes
Structured PICO
Does left-bundle branch area pacing improve positive CRT response at 6-months compared to biventricular pacing in patients with guideline-based CRT indications and LBBB?
P
Population
176 patients with guideline-based CRT indications and left-bundle branch block per Strauss criteria, followed for 12 months.
I
Intervention
Left-bundle branch area pacing (LBBAP-CRT)
C
Comparator
Biventricular pacing (BiVP-CRT)
O
Outcome
Proportion of patients with a positive CRT response at 6-months, defined as either an improved clinical composite score (CCS) or a ≥15% reduction in left ventricular end-systolic volumecomposite
Main Result
Relative Risk: 0.95 (95% CI 0.88–1.02)
Absolute Event Rate: 89.7% vs 94.6%
Discussion
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Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“We now have randomized data showing that [LBBAP] is a very credible CRT option, with procedural advantages in some settings and clinical outcomes that are at least broadly comparable to BiV-CRT in selected populations. But I would still be cautious about overinterpreting the current evidence. These trials are important, but they do not yet justify a one-size-fits-all conclusion that LBBAP should replace conventional CRT across the board.”
Implication
In patients with typical LBBB eligible for CRT, left-bundle branch area pacing was not shown to be non-inferior to biventricular pacing for achieving a positive CRT response at 6 months, although both strategies yielded high response rates.
Abstract
BACKGROUND AND AIMS: Conduction system pacing has emerged as an alternative to biventricular pacing (BiVP) for cardiac resynchronization therapy (CRT). The left-bundle CRT trial evaluated whether left-bundle branch area pacing (LBBAP) is non-inferior to BiVP in patients eligible for CRT. METHODS: The left-bundle CRT trial was a multi-centre, randomized, investigator-initiated, and non-inferiority study. Patients with guideline-based CRT indications and left-bundle branch block per Strauss criteria were randomized to BiVP-CRT or LBBAP-CRT. The primary endpoint was the proportion of patients with a positive CRT response at 6-months, defined as either an improved clinical composite score (CCS) or a ≥15% reduction in left ventricular end-systolic volume. The non-inferiority margin was the lower bound of the 95% confidence interval (CI) and was set at 10%. Patients were followed for 12-months; secondary endpoints included echocardiographic, clinical, and quality-of-life outcomes. RESULTS: The baseline characteristics of the 176 patients randomized to BiVP-CRT (n=84) or LBBAP-CRT (n=92) were similar, except for a wider intrinsic QRS in the LBBAP group: median 172 ms [IQR 158-184] vs. 165 ms [152-180]; P=0.04. Crossovers occurred in 26 patients (14.9%). In the intention-to-treat analysis, the primary endpoint was achieved in 94.6% of BiVP-CRT and 89.7% of LBBAP-CRT patients (RR 0.95; 95% CI 0.88-1.02), not meeting non-inferiority. CCS improved in 77% and 68% of patients randomized to BiVP-CRT and LBBAP-CRT, respectively and 85% and 79% had a ≥15% reduction in left ventricular end-systolic volume. Rates of adverse events and heart failure hospitalization were similar between groups. CONCLUSIONS: In CRT candidates with typical LBBB, LBBAP-CRT was not shown to be non-inferior to BiVP-CRT. Both strategies yielded high response rates and similar clinical outcomes.
Coverage & sources
Journal, society, and media accounts. Useful signal, not independent expert judgment.
Cite This Study
Cano et al. (2026) conducted an RCT in CRT candidates with typical LBBB (n=176). Left-bundle branch area pacing (LBBAP-CRT) vs. Biventricular pacing (BiVP-CRT) was evaluated on positive CRT response at 6-months, defined as either an improved clinical composite score (CCS) or a ≥15% reduction in left ventricular end-systolic volume (RR 0.95, 95% CI 0.88-1.02). Left-bundle branch area pacing was not shown to be non-inferior to biventricular pacing for positive CRT response at 6 months (89.7% vs 94.6%; RR 0.95; 95% CI 0.88-1.02).