家兔心阻抗一阶和二阶微分图的分析

本文对30只家兔的心阻抗一阶和二阶微分图进行了分析,家兔一阶微分图中有A、C、O波和B点,二阶微分图中有a、c、o波和b、p、x、k、f点。但是家兔的b-p间期(快速射血期)比p-x间期(缓慢射血期)长,k-f间期(快速充盈期)比f-a间期(缓慢充盈期)长。结扎冠状动脉前降枝(中上1/3处)和注射垂体后叶素(0.5u/kg)后,阻抗法测定的心收缩间期和心舒间期指标均出现明显改变,结扎冠状动脉组更为显著。注射异丙基肾上腺素(2.5mg/kg)24小时后,仅有心舒间期指标出现异常。三种实验性急性心肌缺血均能使二阶微分图中的正向a波(a′)增大,注射垂体后叶素后10分钟,心电图ST段已复位,但增大的正向a波仍然存在,提示正向a波能够灵敏地反映心脏功能的异常改变。

Analysis of First and Second Derivative Thoracic Impedance Cardiograms of Rabbits

The first and second derivative thoracic impedance cardiograms were investigated in 30 rabbits under acute experimental myocardial ischemia (AMI) and normal conditions. The results indicated that the graph of the rabbit was similar to that of human beings, there were A, C, O, waves and B point in the FDTIC and there were a,c,o, waves and b,p,x,k,f points in the SDTIC. The indices in F and SIDC with relation to the heart contractility and relaxation became obviously abnormal 10 min after tying the anterior descending branch of the left coronary artery (upper and middle one-third) and 3 min after i,v. administraion of pituitrin (0.5u/kg) , but the change of the indices relative with contractility was less following administration of pituitrin than that following the tying of the coronary artery. The indices of relaxation only became adnormal 24 hours after i.v, administration of isoprenaline (2.5mg/kg) , additionally, the positive a-wave (a') in the SDTIC was more sensitive to myocardial ischemia than ST segment in ECG. It suggests that a'-wave may be an important index in early diagnosis of coronary heart disease.