Thompson Richard B, van den Bos Ewout J, Esposito David J, Owen Clarence H, Glower Donald D
Departments of Thoracic Surgery, Box 3851, Duke University Medical Center, Durham, NC 27710, USA.
Eur J Heart Fail. 2003 Dec;5(6):741-9. doi: 10.1016/s1388-9842(03)00152-1.
To date, no data exist on the linearity and, therefore, the usefulness of the preload recruitable stroke work (PRSW) and end-systolic pressure-volume (ESPVR) relationships during acute afterload changes in heart failure.
Our aim was, therefore, to characterize both relationships in a model of ventricular pacing induced heart failure at baseline and during acute changes in afterload.
Dynamic left ventricular volume and transmural pressure were measured in 10 conscious dogs using sonomicrometry and micromanometry under control conditions and during heart failure produced by 3 weeks of rapid right ventricular pacing. Afterload was varied from baseline with intravenous infusions of nitroprusside and phenylephrine. Left ventricular function was assessed using the PRSW and ESPVR relationships.
Cardiac output demonstrated a linear inverse relationship with afterload in both normal and failing hearts (r2>0.5, P<0.001) with failure producing a parallel, downward shift of the afterload (x) vs. cardiac output (y) relationship (P<0.01). Yet, afterload variation did not affect PRSW or ESPVR relationships in either normal or failing hearts (r2<0.12, P>0.05).
Thus, the PRSW and ESPVR relationships are insensitive to acute afterload changes in both failing and normal hearts, and the failing left ventricle is no more afterload-sensitive than the normal heart.
迄今为止，尚无关于心力衰竭患者急性后负荷变化期间预负荷可募集搏功（PRSW）和收缩末期压力-容积（ESPVR）关系的线性以及实用性的数据。
因此，我们的目的是在基线以及急性后负荷变化期间，在心室起搏诱发心力衰竭的模型中对这两种关系进行特征描述。
使用超声测微法和微测压法，在10只清醒犬的对照条件下以及3周快速右心室起搏导致心力衰竭期间，测量动态左心室容积和跨壁压力。通过静脉输注硝普钠和去氧肾上腺素使后负荷相对于基线发生变化。使用PRSW和ESPVR关系评估左心室功能。
正常和衰竭心脏的心输出量均与后负荷呈线性负相关（r2>0.5，P<0.001），心力衰竭导致后负荷（x）与心输出量（y）关系平行向下移位（P<0.01）。然而，后负荷变化在正常或衰竭心脏中均不影响PRSW或ESPVR关系（r2<0.12，P>0.05）。
因此，PRSW和ESPVR关系在衰竭和正常心脏中对急性后负荷变化均不敏感，并且衰竭的左心室与正常心脏相比，对后负荷并不更敏感。
