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Left ventricular function in experimental mitral regurgitation with intact chordae tendineae
H A Hennein1, M Jones, C D Stone
1Surgery Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20894.
The Journal of Thoracic and Cardiovascular Surgery
|April 1, 1993
Summary
This study developed a new animal model for chronic mitral regurgitation, preserving heart structure. The model revealed acute mitral regurgitation temporarily improves left ventricular function, while chronic stages lead to significant impairment.
Area of Science:
- Cardiovascular Research
- Surgical Innovation
- Animal Models
Background:
- Current animal models for mitral regurgitation may independently affect left ventricular function.
- A novel approach is needed to study mitral regurgitation without confounding factors.
Purpose of the Study:
- To develop and validate a new animal model of chronic mitral regurgitation.
- To assess left ventricular function in acute and chronic mitral regurgitation using this model.
Main Methods:
- Created a mitral valve leaflet defect in sheep under cardiopulmonary bypass, preserving annuloventricular continuity.
- Analyzed left ventricular volumes, ejection fraction, and maximal elastance using cineangiography and pressure-volume loops.
Main Results:
- Acute mitral regurgitation transiently increased left ventricular end-diastolic volume and fractional shortening without altering maximal elastance.
- Chronic mitral regurgitation resulted in increased left ventricular volumes and a reduced ejection fraction compared to controls.
Conclusions:
- The developed animal model accurately replicates chronic mitral regurgitation while preserving cardiac integrity.
- Acute mitral regurgitation may acutely enhance left ventricular performance, but chronic conditions lead to progressive dysfunction.