三磷酸腺苷致室性心律失常的机制研究

目的：　研究三磷酸腺苷（ＡＴＰ）对正常和存在触发活动的兔在体心脏电生理作用,以探讨ＡＴＰ致室性心律失常的机制。方法：　应用接触电极记录心内膜单相动作电位（ＭＡＰ）技术,观察ＡＴＰ静脉快速注射对正常心脏ＭＡＰ变化和氯化铯（ＣｓＣｌ）诱发触发活动时使用ＡＴＰ对心脏的影响。　结果：　ＡＴＰ对正常心脏的ＭＡＰ振幅（ＭＡＰＡ）和０相最大上升速率　　（Ｖｍａｘ）影响不大,在初期心率减慢不明显,ＭＡＰ时程（ＭＡＰＤ９０）明显延长,并能诱发早期后除极（ＥＡＤ）,后期心率明显抑制,ＥＡＤ消失,而对存在氯化铯（ＣｓＣｌ）诱发出ＥＡＤ的心脏,具有双重作用,在作用初期对后除极（ＥＡＤ或ＤＡＤ）具有短暂促进作用,尔后迅速抑制。　结论：　ＡＴＰ对不同心脏状态,有不同作用机制,表现为兴奋和抑制双重作用,并具有剂量相关性,值得临床使用上重视。

A study on the mechanism of ventricular arrhythmias induced by adenosine triphosphate

Objective: The goal of this study is to observe the electrophysiological effect of adenosine triphosphate (ATP) on the normal heart or how it triggers activities of the mechanism of arrhythmias induced by ATP. Methods: A Franz 6F catheter was introduced into the left ventricle to record monophasic action potentials (MAPs) using the contact electrode technique to observe the influence to MAP change of normal heart and triggered activities with CsCl-induced when ATP is administered as an intravenous bolus.Results: On one hand ATP has little effects on the amplitude and the maximal upstroke velocity (Vmax) of MAP in the normal heart. But at first the heart rate doesn't slows down appreciably and adenosine-induced early after- depolarization (EAD) that are associated with a prolongation the MAP duration (MAPD90), and in the later period the heart rate clearly slows down and EAD disappears. On the other hand it has biphasic effect on delayed after depolarization (DAD) or EAD induced by CsCl. In the initial stage it promotes after depolarization (EAD or DAD) temporarily and then abolishes them quickly. Conclusion: The effect of ATP is variable in different heart states. It shows the biphasic effects of excitement and repression ,and is related to dosage. This is important to the clinical use of ATP.