Myocardial damage during open heart surgery

1)用途：目的：了解冷停搏液（CP）和电性室颤（VF）体外循环时心肌β-肾上腺素受体（b-受体）和心钠素（ANP）的变化。2）材料与方法：取杂种犬右心房壁和冠状静脉窦血，观察手术和实验过程。用同位素配体法测定心肌b受体。结果：（1）b-受体：常温下VF 60 min时，b-受体明显降低，持续90 min时，b-受体明显升高。这些数据也是从实验中获得的。在CP中，b-受体水平直到120分钟才发生变化。(2)心室颤动时，冠状静脉窦血中ANP浓度有一峰值，而CP中未见。心室颤动时心肌心钠素（ANP）值降低，而心脏起搏时心钠素（ANP）值无变化。结论：（1）心内直视手术室颤持续60 min时，右房心肌ANP及b受体表达减少。另一方面，持续120分钟的CP不影响ANP和b-受体水平。(2)用于心脏直视手术的VF应限制在上述数据的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.