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Updated: May 17, 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
Left ventricular asynchrony in patients with right bundle branch block and normal ejection fraction
Berthold Stegemann1, Henryk Dreger, Bruno Ismer
1Medtronic Inc., Bakken Research Center, Maastricht, The Netherlands. berthold.stegemann@medtronic.com
Pacing and Clinical Electrophysiology : PACE
|November 6, 2012
Summary
Right bundle branch block (RBBB) does not cause left ventricular (LV) asynchrony, but it inverts interventricular asynchrony. Left bundle branch block (LBBB) is linked to both interventricular and LV asynchrony.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Imaging
Background:
- Right bundle branch block (RBBB) and left bundle branch block (LBBB) are conduction abnormalities that can affect left ventricular (LV) function.
- The role of RBBB in inducing LV asynchrony remains controversial.
- Assessing LV asynchrony is crucial for understanding cardiac mechanics and potential interventions.
Purpose of the Study:
- To investigate the presence and degree of LV asynchrony in patients with RBBB, LBBB, or left anterior hemiblock (LAH).
- To compare LV asynchrony in these patient groups with healthy controls.
- To clarify the relationship between specific conduction abnormalities and cardiac asynchrony.
Main Methods:
- Included patients with RBBB (15), RBBB+LAH (13), LBBB (10), and 100 healthy controls, all with normal LV function.
- Assessed interventricular asynchrony via right and LV ejection delay.
- Measured intraventricular delay using tissue synchronicity imaging-guided tissue Doppler imaging.
Main Results:
- Left intraventricular asynchrony was associated with LBBB, not pure RBBB.
- Interventricular delays were negative in RBBB, indicating aortic flow precedes pulmonary flow.
- LBBB was linked to both interventricular and left intraventricular asynchrony.
Conclusions:
- Intraventricular asynchrony in normal LV function is dependent on the presence of LBBB.
- Interventricular asynchrony is inverted in patients with RBBB.
- These findings differentiate the impact of RBBB and LBBB on cardiac synchrony.
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