Bodenhamer R M, Drop L J, Johnson R G, Fowler B N, Geffin G A, Newell J B, O'Keefe D D, Daggett W M
J Surg Res. 1985 Aug;39(2):114-27. doi: 10.1016/0022-4804(85)90168-4.
In 30 dogs on right heart bypass we compared the effects of isoproterenol with those of calcium chloride on myocardial oxygen consumption and on left ventricular function in the setting of ventricular depression produced by ionized hypocalcemia. In 22 dogs (Groups A and B) either isoproterenol or calcium chloride was infused, left ventricular function curves were generated, and end-diastolic pressure vs segment length plots were obtained. In 8 dogs (Group C), with initial hypocalcemia, both isoproterenol and calcium chloride were infused separately in random order to produce an equal decrease in left ventricular end-diastolic pressure at constant mean aortic pressure, heart rate, and cardiac output. Myocardial oxygen consumption and indices of left ventricular function were obtained. In Groups A and B, both drugs, when administered to the ventricle depressed by hypocalcemia, displaced left ventricular function curves upward and to the left. Left ventricular stroke work at constant left ventricular end-diastolic pressure increased (from 13.0 +/- 1.3 to 31.2 +/- 2.3 g X m for isoproterenol; from 13.9 +/- 2.5 to 32.5 +/- 2.5 g X m for calcium chloride). In Group C, there were no significant differences between left ventricular end-diastolic pressure, end-diastolic internal diameter, myocardial oxygen consumption, or peak left ventricular dP/dt in the hypocalcemic periods preceding isoproterenol and calcium chloride infusion. When the two drugs caused matched decreases in left ventricular end-diastolic pressure (-7.4 +/- 0.5 cm H2O for isoproterenol; -7.3 +/- 0.8 cm H2O for calcium chloride) there were similar decreases in end-diastolic internal diameter. However, isoproterenol was associated with a significantly greater (P less than 0.001) myocardial oxygen consumption (13.7 +/- 0.4 ml X 100 g-1 X min-1) than calcium chloride infusion (11.9 +/- 0.4 ml X 100 g-1 X min-1), as well as a greater peak left ventricular dP/dt (P less than 0.005).
在30只接受右心旁路手术的犬中，我们比较了异丙肾上腺素和氯化钙在离子化低钙血症导致心室抑制的情况下对心肌耗氧量和左心室功能的影响。在22只犬（A组和B组）中，分别输注异丙肾上腺素或氯化钙，生成左心室功能曲线，并获得舒张末期压力与节段长度的关系图。在8只犬（C组）中，初始存在低钙血症，以随机顺序分别输注异丙肾上腺素和氯化钙，以在恒定平均主动脉压、心率和心输出量的情况下使左心室舒张末期压力等量降低。记录心肌耗氧量和左心室功能指标。在A组和B组中，当将这两种药物应用于因低钙血症而抑制的心室时，左心室功能曲线向上和向左移位。在恒定的左心室舒张末期压力下，左心室搏功增加（异丙肾上腺素从13.0±1.3增加到31.2±2.3 g·m；氯化钙从13.9±2.5增加到32.5±2.5 g·m）。在C组中，在输注异丙肾上腺素和氯化钙之前的低钙血症期，左心室舒张末期压力、舒张末期内径、心肌耗氧量或左心室最大dp/dt之间无显著差异。当两种药物使左心室舒张末期压力出现匹配性降低时（异丙肾上腺素为-7.4±0.5 cmH₂O；氯化钙为-7.3±0.8 cmH₂O），舒张末期内径也出现类似降低。然而，与输注氯化钙（11.9±0.4 ml·100g⁻¹·min⁻¹）相比，异丙肾上腺素使心肌耗氧量显著增加（P＜0.001，为13.7±0.4 ml·100g⁻¹·min⁻¹），且左心室最大dp/dt也更高（P＜0.005）。
