Influence Of Mitral Valve Size On The Rabbit's Left Ventricular Function

Objectives: To study the way in which different sizes of the mitral valve influence the rabbit's left ventricular function by using the Langendroff model. Methods: A rabbit's aortic valve was excised and fastened onto metallic rings with diameters of either 8mm or 9mm. A Langendroff model thereafter was established and antegrade perfused another rabbit's heart, whose mitral valve was replaced by the processed valve described above, for 30 minutes. The indexes of heart rate(HR), left ventricular systolic pressure (LVSP), left ventricular mean systolic pressure(LVMP), and rate of left ventricular pressure change (LV±dp/dtmax) were then recorded with the MedLab system. Results: Compared with the heart whose mitral valve was replaced with a metallic ring of 9mm, the one implanted with an 8mm-valve is more efficient for all measured indexes. Conclusions: The excessively large size of the prosthesis reduces the left ventricular function, because the large ring of theartificial valve restricts systole of the ventricle.