腔静脉作为研究大静脉电隔离作用模型的实验研究

研究腔静脉的电生理特性和组织学特点看其是否可作为研究肺静脉电隔离作用的简便易行的模型。选择1 0只杂种犬为研究对象 ,记录犬腔静脉的电活动 ,在距腔静脉 心房交界处 2cm和 1cm的部位行电生理检查 ;检查后分别取腔静脉 心房交界处、距交界处 2cm和 1cm的组织行组织学检查。结果 :①犬上腔静脉内均可记录到A波 ,在距上腔静脉 心房交界处 2cm部位起搏能夺获心房 ;只有 2 0 %的下腔静脉在距下腔静脉 心房交界处 1cm可记录到A波 ,起搏能夺获心房。②组织学检查显示腔静脉近心端的中膜层主要由心肌纤维所构成 ,形成环行结构 ,心肌纤维在上腔静脉的延伸约 2～ 3cm ,在下腔静脉则为 1cm左右 ,然后逐渐减少消失。结论 :腔静脉内能记录到A波 ,起搏能夺获心房 ,组织学结构类似肺静脉的心肌袖结构。所以 ,腔静脉可作为研究肺静脉电隔离作用的模型 ,尤其是上腔静脉

The Study on the Vena Cava as An Experimental Model in Electrical I solation of Big Veins

The purpose of the study is to study the electrophysiologic and histolog ical characteristics of vena cava to see whether it could be used as a convenien t model to evaluate electrical isolation of pulmonary veins.Ten dogs were electe d to record the electrical activities of vena cava in dogs and to perform electr ophysiologic examination at 2 cm and 1cm from the veno-atrial junction.After el ectrophysiologic examination,the tissues of the veno-atrial junction,2 cm and 1 cm from the junction were taken respectively for histological examination.Resul ts:①An A wave could be recorded in all superior vena cava(SVC) of dogs,pacing a t 2 cm and 1 cm from the SVC-right atrium junction can capture the atrium.But o nly 20% inferior vena cava (IVC) can record A wave at 1 cm from the IVC-right a trium junction and pacing can capture the atrium.②Histological examination show ed that the tunica media of proximal portion of vana cava was mainly composed o f cardiac muscle fibers forming circular structure.Measured from veno-atrial ju nction,cardiac muscle fibers extended into SVC about 2～3 cm and into IVC about 1 cm and then gradually disappear.Conclusion:An A wave can be recorded in the ve na cava and pacing at vena cava can capture atrium,and the histologic structure of vena cava is similar to sleeves of myocardium surrounded the proximal portion of pulmonary veins.Therefore,vena cava can be used as a convenient model to eva luate electrical isolation of pulmonary veins,especially the SVC.