压力-容积环评价压力负荷型慢性心力衰竭大鼠左心室功能的意义

目的采用压力-容积(P-V)环研究压力超负荷对大鼠左心室血流动力学的影响。方法 13只SD大鼠随机分为2组:假手术(Sham)组(n=7)和心力衰竭(HF)组(n=6)。HF组采用腹主动脉缩窄法制备模型,Sham组只穿线不缩窄。对两组大鼠进行血流动力学检测,大鼠麻醉后经右颈总动脉向左心室内插入Millar导管(SPR-838),记录两组大鼠的P-V变化。结果与Sham组相比,HF组大鼠的心脏(P0.01)和肺脏(P0.05)重量均显著增加。在稳定状态的P-V环中可以看到,和Sham组相比,在压力超负荷的影响下,HF组左心室P-V环明显增高、右移,P-V曲线斜率也明显高于Sham组,左心室收缩/舒张末期压力(P_(es)/P_(ed))、收缩/舒张末容积(V_(es)/V_(ed))、压力衰退的时间常数(Tau)均增高(P0.05),而室内压最大上升速率(dP/dt_(max))、左室压力最大下降速率(-dP/dt_(min))、射血分数(EF)和每搏输出量(SV)均出现降低(P0.05)。结论压力负荷型慢性HF大鼠左心室发生了舒张和收缩功能障碍,并且伴有一定程度的左心室肥大。P-V环能够准确地定性、定量评价大鼠的心功能。

Significance of pressure-volume loop in assessment of left ventricular function in pressure-overload heart failure rats

Objective To determine the effect of chronic pressure-overload on the left ventricular hemodynamics in heart failure (HF) rats by pressure-volume (P-V) loop. Methods A total of 13 SD rats were randomly divided into sham operation (Sham) group (n=7) and HF group (n=6). The rat model of HF was induced by abdominal aorta coarctation, and the rats of the Sham group were inflicted with threading but not narrowing. After the animals were anesthetized, a Millar pressure volume conductance catheter (SPR-838) was inserted into left ventricule through right carotid artery to measure P-V loop. Results Compared with the Sham group, the heart mass (P<0.01) and the lung mass (P<0.05) were increased in the HF group (P<0.05). The steady-state P-V loop showed a notable elevation, rightward shift, and elevated slope of P-V curve in the HF group. Compared with the Sham group, the left ventricular end-systolic pressure/end-diastolic pressure (Pes/Ped), end-systolic volume/end-diastolic volume (Ves/Ved), relaxation time constant calculated by Weiss method (Tau) were all remarkably increased (P<0.05), but the peak rate of pressure rise (dP/dtmax), peak rate of pressure decline (-dP/dtmin), ejection fraction (EF) and stroke volume were obviously decreased in the HF group (P<0.05). Conclusion Pressure-overload results in left ventricular systolic and diastolic dysfunction, with partial hypertrophy at the same time. The P-V loop is a useful method for qualitative and quantitative assessment of left ventricular function in rats.