Yeh F C, Tzeng C C, Chang C L, Chen H I
Division of Anesthesia, Tzu-Chi General Hospital, Hualien, Taiwan, R.O.C.
Acta Anaesthesiol Sin. 1994 Sep;32(3):209-12.
The effects of ketamine on the inotropic and chronotropic responsiveness of heart were examined in spontaneously beating hearts isolated from rabbits by using a modified Langendorff preparation. The changes of maximum left ventricular dP/dt from baseline level after exposing to ketamine 5, 25 and 125 micrograms/ml averaged +7.1% (P < 0.05), +2.8% (P > 0.05) and -42.6% (p < 0.001), respectively. The decreases of heart rate at the three ketamine concentrations averaged 2.4% (P < 0.05), 9.4% (P < 0.01) and 36.8% (P < 0.001), separately. Our data demonstrate that ketamine has dual actions on the cardiac inotropism. It mildly increases cardiac contractility at low concentration whereas at high concentration it depresses myocardium profoundly. Besides, ketamine produces a dose-dependent inhibition on chronotropism directly.
采用改良的Langendorff装置，在离体自搏兔心上观察了氯胺酮对心脏变力性和变时性反应的影响。暴露于5、25和125微克/毫升氯胺酮后，左心室最大dp/dt相对于基线水平的变化平均分别为+7.1%（P<0.05）、+2.8%（P>0.05）和-42.6%（P<0.001）。三种氯胺酮浓度下心率的降低平均分别为2.4%（P<0.05）、9.4%（P<0.01）和36.8%（P<0.001）。我们的数据表明，氯胺酮对心脏变力性有双重作用。低浓度时轻度增加心肌收缩力，而高浓度时则显著抑制心肌。此外，氯胺酮对变时性有直接的剂量依赖性抑制作用。
