[New method for estimating left ventricular myocardial elasticity by vibration analysis].
We solved numerical solutions of Advani-Lee's equation, which treats free vibrations of fluid-filled spherical shells, and forms the basis for non-invasive estimation of left ventricular myocardial elasticity. Numerical results showed that elasticity is approximated by E = 86.5.a2.f2 (E: elasticity (dyn/cm2), a: internal radius (cm), f: eigen-frequency (Hz)). To examine the accuracy of this theoretical equation in estimating elasticity, we made 7 spherical shells of silicone rubber, and compared the estimated elasticity by this equation with that by a standard stretch test. The elasticity calculated by Advani-Lee's equation and by stretch test proved to be nearly identical. Therefore, we concluded that we can estimate the elasticity of a spherical shell using this equation. We calculated the myocardial elasticity at the first heart sound emission in 25 normal persons with a simplified (approximated form of) Advani-Lee's equation. The mean elasticity in normal subjects was (7.04 +/- 2.46) x 10(5) dyn/cm2.
Honda
H
H
First Department of Internal Medicine, Tohoku University School of Medicine, Aoba-ku Sendai.
Koiwa
Y
Y
Ohyama
T
T
Takagi
T
T
Kikuchi
J
J
Hoshi
N
N
Butler
J P
JP
Takishima
T
T
D004548:Elasticity; D006334:Heart Function Tests / Q000379:methods*; D006347:Heart Sounds; D006801:Humans; D016277:Ventricular Function, Left; D014732:Vibration