Right Ventricular Function in Retrograde Cardioplegia for Myocardial Protection : An Experimental Study

杂种狗接受了这项研究，并使用传统的心肺机进行心肺转流术。所有狗的主动脉交叉钳夹总时间为 60 分钟。在第一组中，使用注射器将 4°C 圣托马斯医院溶液注入主动脉根部。每 20 分钟补充一次心脏停跳液，剂量为初始剂量的一半。 II组为逆行停跳液，在60cm高度处从冠状窦点滴法逆行给予相同溶液，补充停跳液的剂量和间隔时间与I组相同。III组为逆行停跳液与II组相同，并结合冰泥局部降温。主动脉阻断60分钟后进行心脏复苏。分别在心脏复苏后15、30、45和60分钟测量右心室功能，如心输出量、右心房压、右心室舒张末压、右心室最大dp/dt和右心室缩短分数。在II组中，心脏复苏后15分钟和30分钟右心房压力较对照值显着升高。另一方面，Ⅲ组右心功能各项指标均出现显着变化。目前的实验研究表明，逆行心脏停跳方法可能会导致右心室灌注不良，导致心脏复苏后早期右心室功能障碍。然而，这种有害作用可以通过右心室局部冷却与冰泥的联合使用来预防。

Mongrel dogs were subjected to this study and were placed on cardiopulmonary bypass using a conventional heart-lung machine. Total aortic cross-clamping time was 60 minutes in all dogs. In group I 4゜C St. Thomas' Hospital solution was injected into the aortic root by the use of a syringe. Cardioplegic solution was replenished every 20 minutes with a half of the initial dose. Group II were the dogs with the retrograde cardioplegia in which the same solution was given retrogradely from the coronary sinus by the drip method at the hight of 60cm, and the replenishing dose and interval of cardioplegia were the same as Group I. Group III was the dogs treated with retrograde cardioplegia identical to Group II and the combined use of topical cooling with ice-slush.The hearts were resuscitated after 60 minutes of aortic cross-clamping. Right ventricular functions such as cardiac output, right atrial pressure, right ventricular enddiastolic pressure, right ventricular max dp/dt, and shortening fraction of the right ventricle were measured 15, 30, 45, and 60 minutes after cardiac resuscitation respectively. In group II, right atrial pressure was significantly elevated from the control value 15 and 30 minutes after cardiac resuscitation. On the other hand, all indices of right ventricular function in Group III showed insignificant change. The present experimental study demonstrated the retrograde cardioplegic method could produce poor right ventricular perfusion resulting in right ventricular dystunction early after cardiac resuscitation. This deleterious effect however could be prevented by the combined sue of topical cooling of the right ventricle with ice-slush.