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Updated: Jul 11, 2026
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
Changes and predictive value of dispersion of repolarization parameters for appropriate therapy in patients with
Nicolas Lellouche1, Carlos De Diego, Gina Akopyan
1UCLA Cardiac Arrhythmia Center, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at UCLA, University of California-Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA.
Insights
Cardiac resynchronization therapy (CRT) impacts repolarization dispersion differently based on patient characteristics. Post-CRT Tpeak-Tend (Tp-e) predicts appropriate implantable cardioverter-defibrillator (ICD) therapy, offering valuable prognostic insight.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- The effect of cardiac resynchronization therapy (CRT) on repolarization dispersion remains debated.
- Long-term CRT benefits for sudden cardiac death require extensive follow-up.
Purpose of the Study:
- To assess the immediate impact of CRT on repolarization dispersion.
- To determine the predictive value of repolarization dispersion parameters for appropriate implantable cardioverter-defibrillator (ICD) therapy.
Main Methods:
- Retrospective analysis of 100 patients with heart failure undergoing CRT-ICD implantation.
- Measurement of ECG indices: QT dispersion, Tpeak-Tend (Tp-e), and Tp-e dispersion before and after CRT.
- Patient criteria included NYHA class III-IV, LVEF ≤35%, and specific QRS characteristics.
Main Results:
- Tpeak-Tend (Tp-e) did not significantly increase post-CRT in biventricular upgrade patients.
- Tp-e significantly increased post-CRT in patients with left bundle branch block or narrow QRS.
- Postimplantation Tp-e was the sole independent predictor of future appropriate ICD therapy (P = .02).
Conclusions:
- CRT's immediate effect on Tp-e varies; it may increase in specific patient subgroups (LBBB, narrow QRS).
- Postimplantation Tp-e serves as a crucial independent predictor for appropriate ICD therapy, aiding risk stratification.
Background:
The impact of cardiac resynchronization therapy (CRT) on dispersion of repolarization is controversial. The benefit of CRT on sudden cardiac death has been demonstrated only after 3 years follow-up.
Objective:
The purpose of this study was to explore the immediate effect of CRT on dispersion of repolarization and to define the value of dispersion of repolarization parameters as predictors of appropriate implantable cardioverter-defibrillator (ICD) therapy.
Methods:
Data from 100 patients who underwent CRT-ICD placement were analyzed retrospectively. Patients had symptoms of New York Heart Association functional class III or IV heart failure, left ventricular ejection fraction < or =35%, and QRS duration >130 ms or QRS < or =130 ms with left intraventricular dyssynchrony. ECG indices of dispersion of repolarization before and immediately after CRT implantation (QT dispersion, Tpeak-Tend [Tp-e], and Tp-e dispersion) were measured.
Results:
In patients who were upgraded to a biventricular system, Tp-e did not increase significantly after CRT. However, Tp-e increased significantly after CRT in patients with left bundle branch block or narrow QRS at baseline. After 12-month follow-up, 22 patients had received appropriate ICD therapy. ICD therapy and no ICD therapy groups had similar baseline characteristics, such as secondary prevention and ischemic cardiomyopathy. Postimplantation Tp-e was the only independent predictor of future ICD therapy (P = .02).
Conclusion:
Immediately after CRT, Tp-e did not increase in patients who received a biventricular upgrade; however, Tp-e did increase in patients with preimplantation left bundle branch block or narrow QRS. Postimplantation Tp-e was the only independent predictor of appropriate ICD therapy.
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