Monash Cardiovascular Research Centre, MonashHeart and Department of Medicine (School of Clinical Sciences at Monash Health), Monash University and Monash Health, Clayton, Victoria, Australia.
PLoS One. 2019 Jan 7;14(1):e0210277. doi: 10.1371/journal.pone.0210277. eCollection 2019.
Both the left ventricular (LV) long-axis peak early diastolic lengthening velocity (e) and long-axis early diastolic excursion (EDExc) decrease with age, but the mechanisms underlying these decreases are not fully understood. The aim of this study was to investigate the relative contributions to aging-related decreases in eand EDExc from LV long-axis systolic excursion (SExc), isovolumic relaxation time (IVRT, as a measure of the speed of relaxation) and LV end-diastolic length (LVEDL).
The study group was 50 healthy adult subjects of ages 17-75 years with a normal LV ejection fraction. SExc, EDExc, eand IVRT were measured from pulsed wave tissue Doppler signals acquired from the septal and lateral walls. Multivariate modelling was performed to identify independent predictors of EDExc and ewhich were consistent for the septal and lateral walls.
EDExc decreased with age and the major determinant of EDExc was SExc, which also decreased with age. There was also a decrease of ewith age, and the major determinant of ewas EDExc. IVRT decreased with age and on univariate analysis was not only inversely correlated with EDExc and e, but also with SExc. IVRT was only a minor contributor to models of EDExc which included SExc, and was an inconsistent contributor to models of ewhich included EDExc. LVEDL decreased with age independent of sex and body size, and was positively correlated with SExc, EDExc and e`.
Major mechanisms underlying the decrease in eseen during aging are the concomitant decreases in long-axis contraction and early diastolic excursion, which are in turn related in part to long-axis remodelling of the left ventricle. After adjusting for the extent of systolic and early diastolic excursion, slowing of relaxation, as reflected in prolongation of the IVRT, makes no more than a minor contribution to aging-related decreases in EDExc and e.
左心室（LV）长轴峰值早期舒张伸长速度（e）和长轴早期舒张位移（EDExc）随年龄增长而降低，但这些降低的机制尚不完全清楚。本研究旨在探讨 LV 长轴收缩位移（SExc）、等容舒张时间（IVRT，作为松弛速度的衡量标准）和 LV 舒张末期长度（LVEDL）对 e和 EDExc 与年龄相关降低的相对贡献。
研究对象为年龄在 17-75 岁之间、左心室射血分数正常的 50 名健康成年人。从间隔壁和侧壁采集的脉冲波组织多普勒信号中测量 SExc、EDExc、e和 IVRT。进行多元建模以确定 EDExc 和 e的独立预测因子，这些预测因子对间隔壁和侧壁都是一致的。
EDExc 随年龄增长而降低，EDExc 的主要决定因素是 SExc，SExc 也随年龄增长而降低。e随年龄增长而降低，e的主要决定因素是 EDExc。IVRT 随年龄增长而降低，在单变量分析中，IVRT 不仅与 EDExc 和 e呈负相关，而且与 SExc 也呈负相关。IVRT 仅对包括 SExc 的 EDExc 模型有较小的贡献，对包括 EDExc 的 e模型贡献也不一致。LVEDL 随年龄增长而降低，与性别和体型无关，与 SExc、EDExc 和 e`呈正相关。
衰老过程中 e降低的主要机制是长轴收缩和早期舒张位移的同时降低，而这又与左心室长轴重塑部分相关。在调整了收缩和早期舒张位移的程度后，IVRT 的延长（反映为松弛速度的减慢）对 EDExc 和 e与年龄相关的降低的贡献不大。
