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Updated: Jul 15, 2026

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

Evidence for electrical remodeling of the native conduction system with cardiac resynchronization therapy

Charles A Henrikson1, David D Spragg, Alan Cheng

  • 1Division of Cardiology, Johns Hopkins University, Baltimore, Maryland 21205, USA. chenriks@jhmi.edu

Pacing and Clinical Electrophysiology : PACE
|April 28, 2007
PubMed

Insights

Cardiac resynchronization therapy (CRT) significantly reduces QRS duration, indicating electrical remodeling in heart failure patients. This therapy optimizes cardiac electrical activation without altering other ECG parameters.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Heart Failure Management

Background:

  • Cardiac resynchronization therapy (CRT) is known to improve hemodynamics and reduce heart failure symptoms.
  • The impact of CRT on the electrical remodeling of the heart has not been extensively studied.

Purpose of the Study:

  • To investigate the effects of CRT on electrical remodeling.
  • To assess changes in surface electrocardiogram (ECG) parameters following CRT.

Main Methods:

  • 25 heart failure patients with various conduction delays underwent temporary VVI pacing to assess native conduction.
  • Surface ECGs were recorded before CRT implantation and after chronic biventricular pacing.
  • QRS duration, QRS axis, PR interval, QTc interval, and heart rate were analyzed.

Main Results:

  • A significant reduction in QRS duration was observed after CRT (155 ms to 144 ms, P=0.0006).
  • The QRS axis also shifted significantly (from -1° to -26°, P=0.03).
  • No significant changes were noted in PR interval, QTc interval, or heart rate.

Conclusions:

  • CRT induces a decrease in surface QRS duration, suggesting electrical remodeling.
  • This electrical remodeling may involve changes in the heart's specialized conduction system or intramyocardial impulse transmission.
Abstract

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