Abstract 14816: Radial Viscoelastic Behavior of Myocardium is Not Affected by Aging
BACKGROUND: Aging has considerable impacts on myocardial function. Previous research based on MRI tissue phase mapping (TPM) suggests that aging may significantly influence regional myocardial motion. However, effect of aging on cardiac viscoelastic behavior has not elucidated yet. In the present work, we have used a previously validated model that uses MRI-TPM data to assess radial viscoelastic behavior of the left ventricle (LV) in different age groups.
METHODS: Thirty nine healthy volunteers with no history cardiovascular disease clusterred into three age groups of 20-40, 40-60 and 60-80. Measurements were performed by a 1.5-T MR system (Siemens Medical Solutions) using gradient echo pulse sequence. Radial velocities of the LV were acquired in basal, midventricular, and apical short-axis slices with thickness of 8 mm (Fig 1A and 1B). LV Radial elastic and viscous-damping functions were acquired through the model developed by Mangual et al (2010). The elastic and viscous-damping functions for each segment were converted into Fourier series representation with seven coefficients. Comparison of the coefficients among the groups was performed using ANOVA with p<0.05 being considered statistically significant.
RESULTS: The Fourier series coefficients of elastic function (κ) followed a similar trend for all the groups (Fig 1C). The viscous-damping function (η) exhibits a very low magnitude with zero average. The trend for the coefficients of viscous-damping function (η) was also found similar among the studied groups (Fig 1D). No statistically significant difference was observed among the Fourier series coefficients of both functions (P>0.05).
CONCLUSION: Despite the fact that the regional myocardial velocites are influenced by aging, no statistically significant changes in LV viscoelastic parameters was found among the studied age groups. Close-to-zero magnitudes of function “η” among the healthy volunteers indicate minimal viscous damping in normal LV.
- © 2011 by American Heart Association, Inc.