英语语法分析

The acute toxicity of isoproterenol is much less than that of epinephrine.

异丙肾上腺素的急性毒性比肾上腺素小得多。

The heart rates of pigs in both groups were observed after isoproterenol (ISO) being injected through femoral vein.

建立模型后对两组动物经股静脉微泵注射异丙肾上腺素（ISO），观察心律改变。

We conducted base tilt table test (BTTT) in all patients and additional isoproterenol tilt table test (ITTT) in 18 patients.

所有老年患者全部完成基础倾斜试验，异丙肾上腺素药物倾斜试验18例。