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Updated: Jun 2, 2026
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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
Electrogram-based optimal atrioventricular and interventricular delays of cardiac resynchronization change
Gregory Golovchiner1, Paul Dorian, Iqwal Mangat
1St. Michael's Hospital, Division of Cardiology, University of Toronto, Toronto, Ontario, Canada. pintera@smh.ca
The Canadian Journal of Cardiology
|April 15, 2011
Summary
Optimizing cardiac resynchronization therapy (CRT) device settings like atrioventricular (AV) and interventricular (VV) delays during exercise is feasible. The QuickOpt algorithm showed these optimal CRT delays can change during physical activity in heart failure patients.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Devices
Background:
- Optimal atrioventricular (AV) and interventricular (VV) delays for cardiac resynchronization therapy (CRT) may differ between rest and exercise.
- Limited data exist on optimizing these delays during physical exertion in heart failure patients.
Purpose of the Study:
- To assess the feasibility and reproducibility of the electrogram-based QuickOpt algorithm for optimizing AV and VV delays at rest and during exercise.
- To determine if optimal CRT delays change during physical activity.
Main Methods:
- A graded treadmill test was performed on 24 patients with CRT implantable cardioverter-defibrillators.
- The QuickOpt algorithm was used to measure AV and VV delays repeatedly before, during, and after exercise.
Main Results:
- QuickOpt-derived AV delays showed variability during exercise, with some patients requiring shorter or longer delays compared to rest.
- Interventricular (VV) delays significantly shifted towards earlier right ventricular pacing during exercise in most patients.
- No correlation was found between changes in AV/VV delays and heart rate.
Conclusions:
- Electrogram-based optimization of CRT delays using QuickOpt is feasible and reproducible at rest and during exercise.
- Optimal AV and VV delays for CRT can individually change during physical activity in heart failure patients.
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