Myocardial damage during open heart surgery

1)目的：了解体外循环中心脏骤停（CP）和心室颤动（VF）时心肌β -肾上腺素受体（b受体）和心房钠素肽（ANP）的变化。2)材料与方法：术中取右心房壁和冠状窦血，实验犬取右心房壁和冠状窦血。采用同位素配体法测定心肌b受体。采用直接放射免疫法检测大鼠血液及心肌ANP浓度，免疫化学法观察心肌形态学变化。3)结果：(1)b受体；在常温VF 60分钟内，b受体明显降低，而在VF持续90分钟时，b受体升高。这一数据也是通过实验得到的。在CP中，b受体水平直到120分钟才发生变化。(2)在VF期间，冠状窦血ANP浓度出现峰值，但在CP中未见峰值，心肌ANP瓣数在VF期间下降，但在CP期间无变化，在光镜和电镜下对心肌ANP的免疫研究基本相同。4)结论：(1)心内直视术后VF持续60 min，右心房心肌ANP和b受体降低。另一方面，持续120分钟的CP对ANP和b受体水平没有影响。(2)根据以上数据，辅助心内直视手术的VF应限制在60分钟内。

1) Purposes: The purposes were to know the changes of beta-adrenal receptor (b-Receptor) and atrial natriuretic peptide (ANP) in the myocardium under cold cardioplegia (CP) and electrical ventricular fibrillation (VF) during extracorporal circulation.2) Materials and Methods: The right atrial wall and coronary sinus blood samples were taken during operations and experiments with mongrel dogs. The myocardial b-receptor was measured by isotope ligand method. The ANP concentration of blood and myocardium were assayed by the direct RIA method, and morphological observations of the myocardium was done by immuno-chemical method.3) Results: (1) b-receptor; During the 60 minutes of VF at normal temperature, b-receptor decreased significantly, however, it increased when VF lasted 90 minutes. This data was also obtained from experiments. In the CP, b-receptor level did not change until 120 minutes. (2) During VF, ANP concentration from coronary sinus blood exhibited a peak, but it could not see in the CP. ANP valves in the myocardium decreased during VF, but did not change during CP. Immuno studies of ANP in the myocardium exhibited almost the same pattern by light and electron microscope.4) Conclusion: (1) 60 minutes lasting of VF under open heart surgery, ANP and b-receptor decreased in the right atrial myocardium. On the other hand, 120 minutes lasting of CP did not influence the ANP and b-receptor levels. (2) VF for the aid of open heart surgery should be limited within 60 minutes from above data.