Nakamura Y, Takeda K, Kadota R, Yagi S
Department of Medicine, Dokkyo University School of Medicine, Tochigi, Japan.
Jpn Heart J. 1993 Jan;34(1):91-101. doi: 10.1536/ihj.34.91.
Recently, the slope (Ec) of the left ventricular (LV) end-systolic force-diameter (Fes-Des) relationship has been proposed as a new index for assessing myocardial contractility. Using this relationship, the effects of ISDN on LV myocardial contractility were evaluated in 10 healthy adult mongrel dogs. After the intravenous infusion of propranolol and atropine to produce autonomic blockade, the inferior vena cava was gradually occluded for 20 sec to decrease preload while the dogs were kept apneic. The LV diameter was measured by ultrasonic crystals and LV pressure was measured by a micromanometer. After the control measurements, the dogs received intravenous ISDN (1, 5, 10, or 50 micrograms/kg/min), and inferior vena caval occlusion was repeated. Ec and the extrapolated diameter intercept (D0) of the LV Fes-Des relationship were determined for each dog from the end-systolic data. The differences in heart rate between the control state and ISDN infusion at any dose were not statistically significant. The Ec and D0 values also showed no significant changes with ISDN infusion (Ec: 80 +/- 19, 83 +/- 20, 84 +/- 17, 82 +/- 24, and 87 +/- 24 g/cm for 0, 1, 5, 10, and 50 micrograms/kg/min, respectively. D0: 1.38 +/- 0.42, 1.38 +/- 0.40, 1.38 +/- 0.38, 1.34 +/- 0.40, and 1.36 +/- 0.40 cm for 0, 1, 5, 10, and 50 micrograms/kg/min, respectively). These findings suggested that intravenous ISDN did not affect myocardial contractility in the normal in situ canine left ventricle.
最近，左心室（LV）收缩末期力-直径（Fes-Des）关系的斜率（Ec）已被提议作为评估心肌收缩力的新指标。利用这种关系，在10只健康成年杂种犬中评估了硝酸异山梨酯（ISDN）对左心室心肌收缩力的影响。在静脉输注普萘洛尔和阿托品以产生自主神经阻滞之后，在犬类保持呼吸暂停的情况下，逐渐闭塞下腔静脉20秒以降低前负荷。通过超声晶体测量左心室直径，并用微测压计测量左心室压力。在进行对照测量后，犬类接受静脉注射ISDN（1、5、10或50微克/千克/分钟），并重复下腔静脉闭塞操作。根据收缩末期数据为每只犬确定左心室Fes-Des关系的Ec和外推直径截距（D0）。任何剂量的ISDN输注时与对照状态下的心率差异均无统计学意义。Ec和D0值在ISDN输注时也未显示出显著变化（Ec：分别为0、1、5、10和50微克/千克/分钟时，80±19、83±20、84±17、82±24和87±24克/厘米。D0：分别为0、1、5、10和50微克/千克/分钟时，1.38±0.42、1.38±0.40、1.38±0.38、1.34±0.40和1.36±0.40厘米）。这些发现表明，静脉注射ISDN不会影响正常原位犬左心室的心肌收缩力。
