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Updated: Jun 7, 2025

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
12:45

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

Published on: December 11, 2017

10.4K

Mechanism and Impact of Left Atrial Dyssynchrony on Long-Term Clinical Outcome During Cardiac Resynchronization

Lars-Egil R Hammersboen1, Marie Stugaard2, Alexis Puvrez3

  • 1Institute for Surgical Research, Oslo University Hospital, Oslo, Norway; Division of Cardiovascular and Pulmonary Diseases, Cardiology Department, Oslo University Hospital. Oslo, Norway; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.

JACC. Cardiovascular Imaging
|November 21, 2024
PubMed

Insights

Left bundle branch block (LBBB) causes left atrial (LA) dyssynchrony. Cardiac resynchronization therapy (CRT) can improve LA dyssynchrony and prognosis when LA reservoir strain is preserved.

Area of Science:

  • Cardiology
  • Cardiac Electrophysiology
  • Echocardiography

Background:

  • Left bundle branch block (LBBB) is known to induce left atrial (LA) dyssynchrony.
  • The long-term prognostic implications of LA dyssynchrony in LBBB patients remain unclear.

Purpose of the Study:

  • To investigate the mechanisms underlying LA dyssynchrony in LBBB.
  • To determine if LA dyssynchrony impacts long-term prognosis in heart failure patients with LBBB.

Main Methods:

  • Prospective multicenter study of 168 heart failure patients with LBBB.
  • Echocardiographic strain imaging assessed LA and left ventricular (LV) dyssynchrony before and after 6 months of cardiac resynchronization therapy (CRT).
  • Long-term outcomes were evaluated over 6 years.

Main Results:

  • Significant reduction in LA dyssynchrony (105 ± 76 ms to 37 ± 68 ms) was observed in CRT responders.
  • A strong correlation (r=0.70) between LA and LV dyssynchrony suggests direct mechanical interaction.
  • The combination of preserved LA reservoir strain (≥18%) and resolved LA dyssynchrony (≤53 ms) after CRT predicted excellent long-term prognosis (HR: 0.11).

Conclusions:

  • LA dyssynchrony in LBBB is primarily driven by direct LV-LA mechanical interactions.
  • Cardiac resynchronization therapy (CRT) enhances diastolic function by increasing LV filling time.
  • Preserved LA reservoir strain and resolved LA dyssynchrony following CRT are associated with superior long-term outcomes in LBBB patients.
Abstract

Keywords:
cardiac resynchronization therapydyssynchronyheart failureleft atrial strainleft bundle branch blockleft ventricular strain

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