应变率成像技术评价正常左室壁等容舒张

目的:应用应变率成像(SRI)技术研究正常人等容舒张期左室壁纵向应变率。方法:记录健康人左室各室壁、各水平纵向应变率曲线,测量等容舒张期正向、负向应变率的峰值SRIVR+、SRIVR-,分别用舒张早期和收缩期峰值应变率SRE和SRS校正,即SRIVR+/SRE、SRIVR-/SRS,测量等容舒张期时相指标,比较各室壁、各水平之间的差异。结果:正常心脏等容舒张期纵向应变率曲线有4种形式;SRIVR+与年龄显著相关,从基底向心尖递减,各室壁间无显著性差异;SRIVR-各室壁间以室间隔为大,从基底向心尖递减,心尖部SRIVR-与年龄显著相关。结论:SRI可定量分析正常人等容舒张期心肌形变,为研究病变心肌等容舒张期变化提供依据。

Characteristics of left ventricular strain rate imaging during isovolumic relaxation period in normal subjects

Objective: To investigate longitudinal strain rate during isovolumic relaxation period of left ventricle(LV) in normal subjects by strain rate imaging(SRI). Methods: The LV wall was divided into six walls and each wall into three segments. SR-Time waves were observed. Both positive and negative peak strain rate in isovolumic relaxation period were measured(SRIVR+, SRIVR-). They were corrected by peak strain rate of systolic and early relaxation period respectively(SRIVR+ SRE, SRIVR- SRS). Time data were also measured. All the parameters were compared among different walls and segments. Results: There were four modes of movement during isovolumic relaxation period. Most segments relaxed. There's no significant difference in SRIVR+ among walls, while from basal to apical level, SRIVR+ decreased. SRIVR+ correlated well with age. Other segments had contracting waves. SRIVR- was larger in interventricular septal walls. From basal to apical level, SRIVR- also decreased. SRIVR- in apical level correlated with age significantly. Conclusions: Relaxation and contraction of LV wall in normal subjects during isovolumic relaxation period can be quantitatively evaluated by SRI, which may be the base of further study on dysfunctional myocardium.