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Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
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Value of extreme left axis deviation in patients with complete left bundle branch block

Guido Vannoni1, Carlos D Labadet1, Giuliana Caminotti1

  • 1División Cardiología, Hospital General de Agudos Dr. Cosme Argerich, Pi y Margal 750, 2nd floor, (1155) Ciudad Autómona de Buenos Aires, Argentina.

Current Problems in Cardiology
|September 12, 2025
PubMed

Insights

In patients with left bundle branch block (LBBB), a leftward QRS axis deviation (LAD) indicates worse systolic function and ventricular remodeling. This finding highlights LAD as a significant marker for identifying high-risk cardiovascular patients.

Area of Science:

  • Cardiology
  • Cardiac Electrophysiology
  • Cardiovascular Imaging

Background:

  • Complete left bundle branch block (LBBB) is linked to increased cardiovascular event risk.
  • The prognostic significance of extreme leftward QRS axis deviation (LAD) in LBBB remains debated.

Purpose of the Study:

  • To determine if LAD (-45°) in LBBB patients serves as a marker for systolic dysfunction.
  • To assess if LAD in LBBB patients is associated with ventricular remodeling.

Main Methods:

  • A cross-sectional cohort study included 102 patients diagnosed with LBBB.
  • Echocardiography was performed to evaluate left ventricular (LV) dimensions, wall thickness, and ejection fraction (EF).

Main Results:

  • Patients with LAD exhibited significantly lower EF (32.2% vs. 46.7%) and increased LV end-diastolic diameter index.
  • LAD demonstrated 45% sensitivity and 88% specificity for identifying reduced EF.
  • Cardiomyopathy was more prevalent in the LAD group (93.1% vs. 61.6%), with a higher incidence of eccentric LV hypertrophy.

Conclusions:

  • In LBBB, LAD (-45°) is associated with impaired systolic function and dilated left ventricles.
  • LAD identifies patients with LBBB who have a higher likelihood of cardiomyopathy and eccentric hypertrophy.
Abstract

Keywords:
Left axis deviationLeft bundle-branch blockLeft ventricle remodelingLeft ventricular function

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