What does this research mean for the field?

LOT-CRT leads to a greater reduction in QRS duration and improved global work efficiency compared to BiV-CRT in heart failure patients after 6 months. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This study aims to compare the effectiveness of left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) versus conventional biventricular CRT (BiV-CRT) in heart failure patients.

February 6, 2026

Mid-term results of combining left bundle branch area pacing with cardiac resynchronization therapy in heart failure patients: a better choice?

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Heart failure requiring cardiac resynchronization therapy (n=70). Intervention: Left bundle branch-optimized CRT (LOT-CRT) vs. Conventional biventricular CRT (BiV-CRT). Primary outcome: Reduction in QRS duration (QRSd) (p=<0.001).

Key Result

Left bundle branch-optimized CRT resulted in a more profound reduction in QRS duration compared to conventional biventricular CRT (42.0 vs. 17.0, P<0.001) at 6-month follow-up.

Key Points

This study aims to compare the effectiveness of left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) versus conventional biventricular CRT (BiV-CRT) in heart failure patients.
Prospective cohort study involving 70 patients receiving CRT implantation.
Patients assigned to LOT-CRT (n=30) or BiV-CRT (n=40) based on cardiologists' decisions.
Assessment before and after 6 months included QRS duration, interventricular mechanical delay, and left ventricular parameters via echocardiography.
LOT-CRT group showed a greater reduction in QRS duration (42.0 vs. 17.0 ms) and peak strain dispersion (72.0 vs. 35.5) than BiV-CRT (P<0.001 for both).
Both groups showed significant improvements in left ventricular structure and function, but LOT-CRT had a higher increase in global work efficiency (24.0 vs. 10.0, P<0.001).
LOT-CRT consistently improved left ventricular dyssynchrony and structure in patients with atrial fibrillation.

Study Design

Type

Cohort (n=70)

Structured PICO

Does left bundle branch-optimized CRT (LOT-CRT) improve electrical and mechanical resynchronization compared to conventional biventricular CRT in heart failure patients eligible for CRT?

Population

70 patients (mean age 66±9 years, 68.6% male) who fulfilled the criteria for cardiac resynchronization therapy (CRT) implantation.

Intervention

Left bundle branch-optimized CRT (LOT-CRT) (n=30)

Comparator

Conventional biventricular CRT (BiV-CRT) (n=40)

Outcome

Electrical and mechanical synchronicity, and left ventricular (LV) structure and function assessed at 6 months (including QRS duration, interventricular mechanical delay, peak strain dispersion, LV dimensions/volumes, global longitudinal strain, and myocardial work).surrogate

LOT-CRT provides greater electrical and mechanical resynchronization than conventional BiV-CRT at 6 months in heart failure patients, though long-term clinical outcomes require further study.

Main Result

Absolute Event Rate: 42% vs 17%

p-value: p=<0.001

Limitations

Short follow-up duration requiring further studies to assess long-term LV remodeling and clinical outcome benefits.

Abstract

Abstract Background About one-third of candidates who received cardiac resynchronization therapy (CRT) remained to be non-responders. Based on the findings that left bundle branch area pacing provided more physiological electrical activation than right ventricular pacing, it was interesting to know whether left bundle branch–optimized CRT (LOT-CRT) would show a better result over conventional biventricular CRT (BiV-CRT). Purpose This prospective cohort study was designed to compare the efficacy of LOT-CRT versus classical BiV-CRT in CRT candidates. Methods 70 patients (66±9 years, 68.6% male) who fulfilled the criteria of CRT implantation were assigned to receive LOT-CRT (n=30) or BiV-CRT (n=40) according to implantation cardiologists’ decisions. Those with atrial fibrillation or flutter (AF) were all given LOT-CRT. Electrical and mechanical synchronicity, left ventricular (LV) structure function were assessed before implantation and after 6 months. The measured parameters included QRS duration (QRSd), interventricular mechanical delay (IVMD), as well as peak strain dispersion (PSD), LV diameter and volume namely left ventricular end-diastolic diameter (LVEDD), left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV), and LV global longitudinal strain (GLS) and myocardial work (MW) using two-dimensional speckle-tracking echocardiography, which consisted of global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). Results Baseline clinical characteristics were comparable between the two groups except that there were 13 (43.3%) patients with AF in the LOT-CRT. During 6-month follow-up, the LOT-CRT group had a more profound reduction in QRSd (42.023.3, 74.5 vs. 17.016.3, 23.8, P0.001) and PSD (72.043.0, 114.3 vs. 35.54.3, 82.0, p=0.001) but not IVMD (29.021.8, 36.8 vs. 34.521.3, 46.0, P=0.626). Both groups exhibited similarly significant improvement in LV structure, ejection fraction (EF), GLS and MW after implantation (Table 1), except that the LOT-CRT group displayed a better increase in GWE (24.011.0,29.3 vs. 10.06.3,14.8, P0.001). Subgroup analysis demonstrated a consistent favorable effect of LOT-CRT in patients with AF on reducing LV dyssynchrony along with recovering LV structure and function (brackets in Table 1). Conclusion LOT-CRT displayed a greater degree of electrical and mechanical resynchronization compared to BiV-CRT at mid-term follow-up. However, further studies with longer follow-up are warranted to investigate whether it will be translated into LV remodeling and outcome benefits.

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