收缩状态的评价是最大心室功率除以末端透缩体积的平方
1Department of Internal Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21205.
Circulation
|October 1, 1991
概括
最大心室功率 (PWRmax) 分于末端透气体积平方 (EDV2) 提供了一个负载独立的心脏收缩率测量. 这一新型指数显示了对心脏功能的非侵入性临床评估的前景.
科学领域:
- 心血管生理学心血管生理学
- 心脏机械学 心脏机械学
- 血液动力学 血液动力学
背景情况:
- 最大心室功率 (PWRmax) 是心脏收缩状态的关键指标.
- 了解PWRmax对预负载,后负载和内状态的敏感性对于其临床应用至关重要.
- 目前用于确定PWRmax的方法在非侵入性评估方面存在局限性.
研究的目的:
- 定义PWRmax对前负载,后负载和内热态状态的依赖性.
- 开发一种基于功率的新型收缩指数,该指数受到负载条件的最小影响.
- 评估这个新指数的非侵入性测定潜力.
主要方法:
- 七只开放胸部,自主阻塞的狗被仪器测量心室压力,体积和大动脉流量.
- 预载荷通过出血而改变,后载荷通过大动脉气球膨胀而改变,并且在药理上改变了无otropic状态.
- 计算PWRmax并将其正常化为终端透气体体积 (EDV) 和EDV平方 (EDV2).
主要成果:
- PWRmax对预负载高度敏感,随着终端透缩体积 (EDV) 的显著变化而显著变化.
- 通过EDV2将PWRmax正常化,显著减少了预加载依赖性,几乎消除了后负载灵敏性.
- PWRmax/EDV2指数与已建立的收缩性指标 (Ees和A) 相对相关性很好,可以通过非侵入性方式确定.
结论:
- 通过EDV2规范化的PWRmax提供了对心脏收缩率的可靠测量.
- 这一指数在很大程度上独立于前负载和后负载变化.
- 这些发现支持这种新型收缩指数的非侵入性临床使用潜力.
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