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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

Cardiac resynchronization therapy in patients with heart failure and conduction abnormalities other than left

Juan M Aranda1, Jamie B Conti, James W Johnson

  • 1University of Florida College of Medicine, Gainesville, Florida 32610, USA. arandjm@mail-cs.med.ufl.edu

Clinical Cardiology
|January 5, 2005
PubMed

Insights

Cardiac resynchronization therapy (CRT) benefits patients with congestive heart failure (CHF) and right bundle-branch block (RBBB) or nonspecific interventricular conduction delay (IVCD), not just left bundle-branch block (LBBB). These patients show improved functional class and quality of life.

Area of Science:

  • Cardiology
  • Heart Failure Management
  • Electrophysiology

Background:

  • Cardiac resynchronization therapy (CRT) is used for congestive heart failure (CHF) with prolonged QRS durations.
  • Previous studies focused on patients with left bundle-branch block (LBBB).
  • The MIRACLE trial showed CRT improves functional capacity in patients with QRS duration ≥ 130 ms.

Purpose of the Study:

  • To evaluate CRT efficacy in CHF patients with conduction abnormalities other than LBBB.
  • To determine if right bundle-branch block (RBBB) and nonspecific interventricular conduction delay (IVCD) subgroups benefit from CRT.

Main Methods:

  • Retrospective analysis of patients from the MIRACLE trial.
  • Patients categorized into LBBB, RBBB, and IVCD subgroups.
  • Comparison of CRT response versus no CRT at baseline and 6-month follow-up.

Main Results:

  • 313 LBBB, 43 RBBB, 35 IVCD patients analyzed.
  • RBBB patients showed significant functional class improvement (p=0.001).
  • IVCD patients showed significant quality of life improvement (p=0.038).
  • RBBB and IVCD groups improved exercise time and peak oxygen consumption post-CRT.
  • 82% of RBBB patients had concomitant left-sided conduction abnormalities.

Conclusions:

  • Patients with CHF, RBBB, and IVCD benefit from CRT.
  • Concomitant left-sided conduction abnormalities may explain RBBB response to CRT.
  • Further subgroup analyses in CRT trials are needed to confirm these findings.
Abstract

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