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QRS duration in left bundle branch block does not affect left ventricular twisting in chronic systolic heart failure

Paola Attanà1, Alessandro Paoletti Perini1, Carmine Domenico Votta1

  • 1Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.

Clinical Physiology and Functional Imaging
|August 1, 2014
PubMed

Insights

In chronic systolic heart failure patients, prolonged QRS duration and left bundle branch block (LBBB) do not impact left ventricular (LV) torsion or twisting/untwisting rates. This suggests QRS duration is not a determinant of LV mechanics in this population.

Area of Science:

  • Cardiology
  • Cardiac Physiology
  • Echocardiography

Background:

  • Left ventricular (LV) torsion is a critical indicator of LV performance.
  • Factors influencing LV torsion include QRS duration and left bundle branch block (LBBB).
  • Understanding these influences is crucial for managing chronic systolic heart failure (HF).

Purpose of the Study:

  • To investigate the effect of QRS prolongation in LBBB on global LV twist and twisting/untwisting rates.
  • To assess the relationship between QRS duration and LV mechanics in chronic systolic HF patients.

Main Methods:

  • Prospective evaluation of 100 chronic HF patients (ejection fraction ≤ 35%) and 30 healthy controls.
  • HF patients categorized by QRS duration: <120 ms (n=49), 120-150 ms (n=28, LBBB), and >150 ms (n=23, LBBB).
  • Standard and 2D speckle-tracking echocardiography used; statistical analysis included ANOVA and linear regression.

Main Results:

  • Control subjects exhibited significantly higher LV torsion parameters than HF patients.
  • No significant differences in global twist, twist rate, or untwist rate were observed among the three HF groups based on QRS duration.
  • Linear regression analysis revealed no correlation between QRS duration and any LV torsion parameter in HF patients.

Conclusions:

  • QRS duration and LBBB morphology do not significantly alter LV twisting and untwisting in patients with chronic severe systolic heart failure.
  • These findings indicate that QRS duration is not a primary determinant of LV mechanical function in this patient cohort.
Abstract

Keywords:
QRS durationheart failureleft bundle branch blockleft ventricular twistspeckle-tracking echocardiography

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