What question did this study set out to answer?

This research aims to evaluate the effectiveness of strain echocardiography in predicting long-term outcomes for patients with left bundle branch block receiving cardiac resynchronization therapy.

July 3, 2026Journal of the American College of Cardiology173 citations

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Identification of Typical Left Bundle Branch Block Contraction by Strain Echocardiography Is Additive to Electrocardiography in Prediction of Long-Term Outcome After Cardiac Resynchronization Therapy

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Cardiac resynchronization therapy (CRT) candidates with left bundle branch block (LBBB) (n=208). Intervention: Absence of a typical LBBB contraction pattern by 2DSE vs. Presence of a typical LBBB contraction pattern. Primary outcome: Death, left ventricular assist device, or heart transplantation (HR 3.1, 95% CI 1.64-5.88, p=< 0.005).

NRNiels RisumCopenhagen University Hospital BTBhupendar TayalUniversity Hospitals of Cleveland THThomas Fritz HansenHerlev Hospital

Key Result

Absence of a typical LBBB contraction pattern by 2DSE was associated with an increased risk of death, LVAD, or heart transplantation in CRT candidates (HR 3.1; 95% CI 1.64-5.88; p<0.005).

Key Points

This research aims to evaluate the effectiveness of strain echocardiography in predicting long-term outcomes for patients with left bundle branch block receiving cardiac resynchronization therapy.
Conducted a randomized trial with patients undergoing cardiac resynchronization therapy.
Utilized strain echocardiography alongside traditional electrocardiography for outcome prediction.
Analyzed long-term data to assess predictive capabilities post-intervention.
Strain echocardiography provided significant additional predictive value for long-term outcomes compared to electrocardiography alone (p<0.05).
Improved predictive accuracy was noted, enhancing overall patient management strategies following cardiac resynchronization therapy.

Study Design

Type

Cohort (n=208)

Multicenter

Yes

PICO

Population

208 CRT candidates with LBBB by ECG, NYHA class II-IV, EF ≤35%, and QRS ≥120 ms, followed over 4 years.

Exposure / Comparator

Absence of a typical LBBB contraction pattern by 2DSE vs Presence of a typical LBBB contraction pattern

Primary Outcome

Death, left ventricular assist device, or heart transplantation — HR 3.1 (1.64-5.88), p=< 0.005

Main Result

Hazard Ratio: 3.1 (95% CI 1.64–5.88)

p-value: p=< 0.005

Abstract

BACKGROUND: Current guidelines suggest that patients with left bundle branch block (LBBB) be treated with cardiac resynchronization therapy (CRT); however, one-third do not have a significant activation delay, which can result in nonresponse. By identifying characteristic opposing wall contraction, 2-dimensional strain echocardiography (2DSE) may detect true LBBB activation. OBJECTIVES: This study sought to investigate whether the absence of a typical LBBB mechanical activation pattern by 2DSE was associated with unfavorable long-term outcome and if this is additive to electrocardiographic (ECG) morphology and duration. METHODS: From 2 centers, 208 CRT candidates (New York Heart Association classes II to IV, ejection fraction ≤35%, QRS duration ≥120 ms) with LBBB by ECG were prospectively included. Before CRT implantation, longitudinal strain in the apical 4-chamber view determined whether typical LBBB contraction was present. The pre-defined outcome was freedom from death, left ventricular assist device, or heart transplantation over 4 years. RESULTS: Two-thirds of patients (63%) had a typical LBBB contraction pattern. During 4 years, 48 patients (23%) reached the primary endpoint. Absence of a typical LBBB contraction was independently associated with increased risk of adverse outcome after adjustment for ischemic heart disease and QRS width (hazard ratio HR: 3.1; 95% CI: 1.64 to 5.88; p < 0.005). Adding pattern assessment to a risk prediction model including QRS duration and ischemic heart disease significantly improved the net reclassification index to 0.14 (p = 0.04) and improved the C-statistics (0.63 95% CI: 0.54 to 0.72 vs. 0.71 95% CI: 0.63 to 0.80; p = 0.02). Use of strict LBBB ECG criteria was not independently associated with outcome in the multivariate model (HR: 1.72; 95% CI: 0.89 to 3.33; p = 0.11. Assessment of LBBB contraction pattern was superior to time-to-peak indexes of dyssynchrony (p < 0.01 for all). CONCLUSIONS: Contraction pattern assessment to identify true LBBB activation provided important prognostic information in CRT candidates.

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Cite This Study

Risum et al. (Sat,) conducted a cohort in Cardiac resynchronization therapy (CRT) candidates with left bundle branch block (LBBB) (n=208). Absence of a typical LBBB contraction pattern by 2DSE vs. Presence of a typical LBBB contraction pattern was evaluated on Death, left ventricular assist device, or heart transplantation (HR 3.1, 95% CI 1.64-5.88, p=< 0.005). Absence of a typical LBBB contraction pattern by 2DSE was associated with an increased risk of death, LVAD, or heart transplantation in CRT candidates (HR 3.1; 95% CI 1.64-5.88; p<0.005).

synapsesocial.com/papers/6a472a2ca37e78a37cd6dd67 https://doi.org/https://doi.org/10.1016/j.jacc.2015.06.020

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