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Permanent Ligation of the Left Anterior Descending Coronary Artery in Mice: A Model of Post-myocardial Infarction Remodelling and Heart Failure
Published on: December 2, 2014
Left bundle branch block induces ventricular remodelling and functional septal hypoperfusion.
Kevin Vernooy1, Xander A A M Verbeek, Maaike Peschar
1Department of Physiology, Cardiovascular Research Institute Maastricht, PO Box 616, 6200 MD Maastricht, The Netherlands. k.vernooy@fys.unimaas.nl
European Heart Journal
|December 24, 2004
Summary
Isolated left bundle branch block (LBBB) causes left ventricular (LV) remodeling, including decreased ejection fraction and asymmetric hypertrophy. This occurs due to asynchronous activation leading to altered septal workload and reduced blood flow.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Cardiovascular Physiology
Background:
- Left bundle branch block (LBBB) is associated with left ventricular (LV) abnormalities such as dilatation, hypertrophy, and septal perfusion defects.
- The causal relationship between isolated LBBB and these LV changes remains unclear.
Purpose of the Study:
- To investigate whether isolated left bundle branch block (LBBB) induces left ventricular (LV) dilatation, hypertrophy, and septal perfusion defects.
- To determine the long-term effects of LBBB on LV structure and function.
Main Methods:
- Induction of LBBB in eight dogs using radiofrequency ablation.
- Assessment of LV dimensions, ejection fraction, and wall mass via echocardiography over 16 weeks.
- Measurement of myocardial blood flow (MBF) and systolic circumferential shortening (CS(sys)) using microspheres and MR tagging, respectively.
Main Results:
- LBBB induced significant LV dilatation, increased LV wall mass, and asymmetric hypertrophy (decreased septal-to-lateral wall mass ratio).
- Septal MBF and CS(sys) decreased, while LV lateral wall values increased, indicating altered regional function and perfusion.
- These changes in MBF and CS(sys) remained stable over 16 weeks, and myocardial hibernation was absent.
Conclusions:
- Asynchronous ventricular activation in LBBB causes redistribution of circumferential shortening and myocardial blood flow.
- Over the long term, LBBB leads to left ventricular remodeling.
- Septal hypoperfusion during LBBB is primarily driven by reduced septal workload.
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