The Effects of Aging and Fitness on Myocardial Relaxation and Compliance

Abstract

0582 Background: Normal aging is associated with changes in myocardial relaxation and compliance, which impair filling of the heart at low pressures. It is unclear if these changes are due to the inherent properties of the aged heart or are secondary to deconditioning. The goal of this study was to determine if exercise training could alter the natural history of diastolic dysfunction and preserve left ventricular (LV) relaxation and compliance. Methods: 15 young (35 ± 10 yrs), 13 healthy but sedentary seniors (70 ± 4 years) and 12 fit seniors (68 ± 3 years) were enrolled. The fit seniors participated in > 25 years of continuous athletic training. Transthoracic echocardiograms were obtained on the subjects at rest and interpreted blindly to determine: 1) mitral inflow patterns (E/A ratio) and relaxation times (early mitral inflow deceleration time (DT), isovolumetric relaxation time (IVRT)), 2) Lateral and septal mitral annular diastolic myocardial motion velocities (Em lateral and Em septal), 3) Color m-mode to derive intraventricular pressure gradient (IVPG) and propagation velocity of early mitral inflow (Vp). In addition to the echo data, we measured PCWP, at baseline, and at 5 levels of cardiac filling to derive LV pressure-volume curves (static compliance). Results: Echocardiographic VariablesTableConclusions: Cardiac compliance deteriorated with aging, but was preserved by lifelong exercise training. In contrast measures of dynamic relaxation were only partially restored by exercise. We suggest that exercise training preserves ventricular compliance to a greater degree than ventricular relaxation during healthy aging, which may be a specific marker of cardiac senescence.