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Updated: May 25, 2026
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Transthoracic Echocardiographic Examination in the Rabbit Model
Published on: June 1, 2019
Electromechanical and structural alterations in the aging rabbit heart and aorta
Leroy L Cooper1, Katja E Odening, Min-Sig Hwang
1Cardiovascular Research Center, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA.
American Journal of Physiology. Heart and Circulatory Physiology
|February 7, 2012
Summary
Aging stiffens the aorta and heart, slowing electrical conduction and increasing ventricular fibrillation risk. These changes in older rabbits highlight mechanisms behind age-related sudden cardiac death.
Area of Science:
- Cardiovascular Physiology
- Aging Research
- Cardiac Electrophysiology
Background:
- Aging is a significant risk factor for cardiac arrhythmias and sudden cardiac death (SCD).
- Understanding the specific cardiovascular changes associated with aging is crucial for mitigating these risks.
Purpose of the Study:
- To investigate aging-related electrical, functional, and structural alterations in the heart and vasculature.
- To elucidate the mechanisms contributing to increased arrhythmogenic risk in aging.
Main Methods:
- Comparison of young and old New Zealand White rabbits using in vivo hemodynamic, electrophysiological, and echocardiographic studies.
- Ex vivo analysis including optical mapping, magnetic resonance imaging (MRI), and histochemistry.
Main Results:
- Old rabbits exhibited increased aortic stiffness and myocardial elastance (both diastolic and systolic).
- Age-related slowing of ventricular and His-Purkinje conduction, altered conduction anisotropy, and higher ventricular fibrillation inducibility were observed.
- Histochemistry revealed increased ventricular fibrosis, and MRI showed deterioration of the Purkinje fiber network and altered myocardial structure in older rabbits.
Conclusions:
- Aging causes parallel stiffening of the aorta and heart, increasing both systolic and diastolic stiffness.
- Fibrosis and altered myocardial structure contribute to anisotropic conduction velocity, potentially leading to ventricular fibrillation in aging hearts.
- The aging rabbit model effectively elucidates age-related cardiac changes predisposing to arrhythmias and SCD.
