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Updated: May 1, 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

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Outcomes in pacemaker-dependent patients upgraded from conventional pacemakers to cardiac resynchronization

Evan Adelstein1, David Schwartzman1, Raveen Bazaz1

  • 1University of Pittsburgh Heart and Vascular Institute, Pittsburgh, Pennsylvania.

Heart Rhythm
|March 25, 2014
PubMed

Insights

Patients without coronary artery disease (CAD) have a lower risk of shocks when upgraded to a CRT-defibrillator. Cardiac resynchronization therapy-pacemakers may be suitable for these patients.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Devices

Background:

  • Cardiac resynchronization therapy (CRT) benefits pacemaker-dependent patients with left ventricular dysfunction.
  • Patients at low risk for ventricular tachyarrhythmias may be suitable for upgrade to a CRT-defibrillator or CRT-pacemaker.

Purpose of the Study:

  • To investigate if coronary artery disease (CAD) predicts a higher risk of appropriate shocks in pacemaker-dependent patients upgraded to a CRT-defibrillator.
  • To assess the role of myocardial scar in CAD-related ventricular arrhythmias.

Main Methods:

  • 157 pacemaker-dependent patients with left ventricular ejection fraction (LVEF) ≤35% and no prior sustained ventricular arrhythmias were upgraded to CRT-defibrillators.
  • Patients were grouped based on the presence (n=75) or absence (n=82) of significant CAD.
  • Outcomes including survival, appropriate shocks, antitachycardia pacing, complications, and LVEF changes were compared.

Main Results:

  • Patients with CAD had higher mortality (HR 2.55, P=.001) and a significantly higher risk of appropriate shocks (1 per 26 person-years vs. 1 per 362 person-years).
  • Of 12 patients receiving appropriate shocks, 11 had CAD.
  • LVEF improvement and end-systolic volume reduction were similar between groups, but CAD patients experienced more comorbidities.

Conclusions:

  • Pacemaker-dependent patients without significant CAD have better survival and a low risk of appropriate shocks after upgrading to a CRT-defibrillator.
  • Cardiac resynchronization therapy-pacemakers may be a more appropriate choice for pacemaker-dependent patients without CAD.
Abstract

Keywords:
Cardiac resynchronization therapyCoronary artery diseaseImplantable cardioverter-defibrillatorsPacemakers

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