温血或冷晶体心脏停搏液对体外循环术后房性心律失常发生的影响

The Effect of Warm Blood Cardioplegia or Cold Crystalloid Cardioplegia on the Occurrence of Post-Extracorporeal Circulation Atrial Arrhythmias in Canine

目的 了解不同的心肌保护方法是否对体外循环 (ECC)术后房性心律失常有影响。 方法 将 12只成年杂交犬随机分为两组 ,A组 :6只犬 ,用持续温血心脏停搏液灌注 ;B组 :6只犬 ,用冷晶体心脏停搏液灌注和局部低温。两组动物主动脉阻断时间均为 30分钟。记录术前及术后 1～ 5天 2 4小时动态心电图 ,计算标准化房性心律失常 ,标准化室性心律失常和 2 4小时平均心率。 结果 ECC后两组动物均未出现心房颤动。尽管术后 A组标准化房性心律失常率高于 B组 (P<0 .0 5 ) ,但两组动物术前、术后标准化房性心律失常率无明显变化 ,标准化室性心律失常率亦无明显变化。此外 ,两组动物术后 2 4小时平均心率亦升高 ,且 B组高于 A组 (P<0 .0 5 )。 结论 不同的心肌保护方法对 ECC术后房性心律失常的发生无明显影响。

Objective\ It is not conclusive whether different methods of myocardial protection have a distinct effect on postoperative atrial arrhythmias(AA). The objectives of this study were to evaluate the effect of the different methods of myocardial protection on the occurrence of post extracorporeal circulation(ECC)AA.\ Methods Twelve adult mongrel canines were divided into two groups. Group A( n=6) received continuous warm blood cardioplegia and was maintained at a systemic temperature of 38℃ throughout the experiment. Group B ( n=6) received cold crystalloid cardioplegia at 31℃ and topical hypothermia. Anesthesia was induced and maintained by sodium pentobarbital and isoflurane. The heart was exposed through a right thoracotomy. ECC was established by using a single venous cannula. The arterial cannula was placed in the right femoral artery. The crossclamp time for both groups was 30 minutes. Each animal's electrocardiogram(ECG) was continuously recorded for 24 hours before surgery and for the first five postoperative days using a two channel Holter monitor. The data were analyzed for heart rate and arrhythmias. Atrial and ventricular arrhythmias were normalized with one ectopic beat divided per one thousand QRS waves. The mean heart rate at 24 hours was calculated.\ Results\ Postoperative atrial fibrillation(AF) did not appear. Normalized ventricular ectopy and normalized supraventricular ectopy did not increase in either group except for an increase in the values of normalized ventricular ectopy of group A at the 2nd postoperative day ( P< 0 05) . Although the values of normalized supraventricular ectopy of group A were higher than those of the group B ( P< 0 05) , there were no difference in normalized supraventricular ectopy before or after ECC in the group A ( P> 0 05) . In addition mean heart rate increased significantly in both groups, with higher values in the group B ( P< 0 05) .\ Conclusion\ The results of the study suggest that ECC with different methods of myocardial protection does not cause postoperative AF and does not seem to be major factor in postoperative AA. However further studies are needed to elucidate the underlying mechanisms of postoperative AA.