增加前、后负荷对右心室心肌收缩性指标的影响

EFFECT OF INCREASING PRELOAD AND AFTERLOAD ON THE MYOCARDIAL CONTRACTILITY INDICES OF RIGHT VENTRICLE

分别用快速输注低分子右旋糖酐溶液、注射异丙肾上腺素和开胸后肺泡加压方法,增加7只狗的右心室前负荷、心肌收缩性和后负荷。比较观察实验中常用右心室心肌收缩性指标的变化情况。结果表明:右室dp/dt max和Vpm对变力性因素最敏感,但也受到心脏负荷变化的明显影响,其余右室指标或不敏感或变异很大。右室dp/dt max、Vpm比左室相应指标更易受呼吸波动干扰。这些指标都不宜单独地作为右心室收缩性的观察指标。同时观察右室dp/dt max、Vpm可定性地了解右心室收缩性和负荷的变化趋势。

Preload, afterload and contractility of right ventricle were increased experimentally in 7 dogs by means of rapid infusion of dextran, increase of alveolar pressure after toracotomy and injection of isoprenaline. The changes of the indices of myocardial contractility of the right ventricle were compared and observed. The dp/dt max and Vpm were very sensitive to the inotropic factor, but were greatly influenced by the change of the myocardial load. The rest indices of the right ventricle were not sensitive or scattered widely dp/dt max and Vpm of the right ventricle were more susceptible to the interference of respiration than those of the left ventricle. None of these indices can be properly used as a single index to indicate the right ventricle contractility. Observing dp/dt max and Vpm of the right ventricle we can qualitatively understand the changing trend of the contractility and load of the right ventricle.