Williams R V, Lorenz J N, Witt S A, Hellard D T, Khoury P R, Kimball T R
Noninvasive Cardiac Imaging and Hemodynamic Research Laboratory, University of Cincinnati College of Medicine, Ohio 45229, USA.
Am J Physiol. 1998 May;274(5):H1828-35. doi: 10.1152/ajpheart.1998.274.5.H1828.
The purposes of this study were to assess load-independent, end-systolic relationships in mice and compare these relationships to ejection phase indexes in assessing contractility. In 13 mice, ejection phase indexes (shortening fraction and velocity of fiber shortening) and end-systolic relationships [pressure-dimension relationship (ESPDR) and stress-velocity relationship (ESSVR)] were determined using M-mode echocardiography and simultaneous left ventricular pressure. Load was altered with phenylephrine and nitroprusside. Contractility was increased with dobutamine and decreased by induction of hypothyroidism. Ejection phase indexes increased with dobutamine infusion but were not significantly decreased with hypothyroidism. However, end-systolic relationships changed significantly with both dobutamine (gamma-intercepts: ESPDR from 22 to 48 mmHg, ESSVR from 3.7 to 6.6 circ/s, P < 0.05) and hypothyroidism (gamma-intercepts: ESPDR from 22 to 11 mmHg, ESSVR from 3.7 to 3.2 circ/s, P < 0.05). We conclude that end-systolic indexes can be accurately measured in the intact mouse by echocardiography with simultaneous left ventricular pressure recording and appear to be more sensitive to inotropic state than ejection phase indexes.
本研究的目的是评估小鼠中与负荷无关的收缩末期关系，并在评估收缩性时将这些关系与射血期指标进行比较。在13只小鼠中，使用M型超声心动图和同步左心室压力测定射血期指标（缩短分数和纤维缩短速度）以及收缩末期关系[压力-维度关系（ESPDR）和应力-速度关系（ESSVR）]。用去氧肾上腺素和硝普钠改变负荷。用多巴酚丁胺增加收缩性，通过诱导甲状腺功能减退降低收缩性。多巴酚丁胺输注时射血期指标增加，但甲状腺功能减退时未显著降低。然而，收缩末期关系在多巴酚丁胺（γ截距：ESPDR从22至48 mmHg，ESSVR从3.7至6.6次/秒，P<0.05）和甲状腺功能减退（γ截距：ESPDR从22至11 mmHg，ESSVR从3.7至3.2次/秒，P<0.05）时均有显著变化。我们得出结论，通过超声心动图同步记录左心室压力，可以在完整小鼠中准确测量收缩末期指标，并且收缩末期指标似乎比射血期指标对变力状态更敏感。
