The age dependence of left ventricular filling efficiency.

Echocardiography has emerged as the preferred modality by which diastolic function (DF) is assessed for clinical or research purposes. Echocardiographic indexes and parameters of DF such as E/A, DT, E/E', etc., deteriorate with advancing age. Whether the efficiency of filling depends on age is unknown. To better characterize the filling process and DF in causal rather than correlative terms, we have previously modeled diastole kinematically. We introduced and validated a dimensionless measure of DF termed the kinematic filling efficiency index (KFEI). In the present study, we determined the effect of aging on DF in terms of KFEI in 72 control subjects without cardiovascular-related diseases or pathologies. We also evaluated the age dependence of other conventional parameters of DF. In concordance with other noninvasive DF measures known to decrease with age, KFEI decreases and correlates very strongly with age (R2=0.80). Multivariate analysis showed that age is the single most important contributor to KFEI (p=0.003). We conclude that KFEI provides novel insight into DF impairment mechanisms because of aging. These results support the clinical value of KFEI and advance our ability to characterize DF in mechanistic and quantitative terms based on the efficiency of filling.