Objective:To compare the difference in stiffness between the normal and hypertrophic isolated myocardium in rabbits by analyzing the stress-strain relationship of free wall with our prototype load-deformation experimental device

and to explore the feasibility of detecting myocardiial stiffness by indentation test.Methods:The animal model of left ventricular hypertrophy was established with the method of “two-kidney

one clip” hypertension in rabbits.Forty-five rabbits were divided into three groups:Group Ⅰ-control group(N

n =15);Group Ⅱ-two—month group after operation(2M

n =15);Group Ⅲ-three—month group after operation(3M

n =15).To assess myocardial stiffness

the stress-strain relationsips of the normal and hypertrophic isolated myocardial free wall were analysed by utilizing our prototype load-deformation experimental device when the different forces were exerted perpendicularly.Results:The stress-strain relationship of the normal and hypertrophic isolated myocardial free wall could be fitted to a typical exponential equations:Y=Ae BX ( r =0.874～0.912).The stress-strain relationships was linear within the scope of a certain stress.The slopes of the linear equation in GroupⅢ were maximum.The slopes of the linear equation in GroupⅠ were minimum.There were significant differences among the three groups( P <0.05).Conclusion:These data suggest that the stiffness of the hypertrophic myocardium induced by the two-kidney

one-clip renal hypertension in rabbit is greater than that of the normal myocardium.The difference between the stiffness of them could be detected by indentation test.