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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

Optimization of pacing for patients receiving ineffective cardiac resynchronization therapy

Nobuhiko Ueda1, Satoshi Oka1, Kohei Ishibashi1

  • 1Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan.

Heart Rhythm
|October 19, 2025
PubMed

Insights

High ineffective cardiac resynchronization therapy (CRT) pacing, often due to pseudo-fusion or latency, is linked to poor outcomes. Optimizing pacing delays can significantly reduce ineffective CRT and improve patient response.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Device Technology

Background:

  • Effective pacing is crucial for cardiac resynchronization therapy (CRT) success.
  • High rates of ineffective CRT (i-CRT) are associated with adverse patient prognoses.
  • Characteristics and optimal management of high %i-CRT remain poorly understood.

Purpose of the Study:

  • To investigate the specific patient characteristics associated with high ineffective CRT (%i-CRT).
  • To evaluate the efficacy of pacing optimization strategies in patients with high %i-CRT.
  • To identify common causes of high %i-CRT and their impact on CRT response.

Main Methods:

  • Assessed 225 patients using the EffectivCRT system to measure %i-CRT.
  • Defined CRT response as improved LVEF (≥10%) and/or reduced LVESV (≥15%).
  • Identified high %i-CRT as >2.0% and analyzed causes like pseudo-fusion or latency.

Main Results:

  • 16% of patients (36/225) exhibited high %i-CRT, showing significantly lower CRT response rates (48% vs. 76%).
  • Pseudo-fusion or latency were primary causes of high %i-CRT, occurring earlier and at higher levels.
  • Pacing optimization in 10 patients reduced %i-CRT from 64.6% to 6.4% and QRS duration from 165 ms to 138 ms, converting 3 non-responders to responders.

Conclusions:

  • High i-CRT, particularly with latency or pseudo-fusion, emerges early in CRT therapy.
  • Optimization of atrioventricular or interventricular delays effectively reduces i-CRT.
  • Pacing optimization improves CRT effectiveness and shortens QRS duration, potentially converting non-responders.
Abstract

Keywords:
Cardiac resynchronization therapyHeart failureIneffective pacingLatencyOptimization

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