NONINVASIVE MEASUREMENT OF LEFT-VENTRICULAR MYOCARDIAL ELASTICITY

We examined Advani and Lee's equation (AL(eq)) and a dimension analysi s-derived equation (DA(eq)), both of which treat vibration of the elas tic spherical shell and are able to estimate elasticity of the shell n oninvasively when the sizes and eigenfrequency are provided. We confir med that AL(eq) was numerically identical to DA(eq) and that both equa tions gave the precise elasticity of the silicone shell. Then we estim ated left ventricular (LV) myocardial elasticity noninvasively at the moment of the first heart sound emission (1HS) in 25 healthy subjects and 14 hypertrophic cardiomyopathy (HCM) patients, based on the LV eig enfrequency detected by an intraesophageal miniature vibration sensor. HCM patients had a higher mean value of LV myocardial elasticity at 1 HS than healthy subjects [102.3 +/- 33.4 vs. 70.7 +/- 24.4 kPa, P < 0. 01 (Pa = N/m(2) = 10 dyn/cm(2))]. We thereby demonstrated the possibil ity of a noninvasive estimate of myocardial elasticity.