【摘要】 应用漂浮微电极记录跨膜动作电位(TAP)和接触电极记录单相动作电位(MAP)两项技术,研究了 CsCl 诱发的猫在体心脏的触发性活动。结果表明,静脉注射 CsCl(0.5mmol/kg)后10s,左心室外膜 TAP 和 MAP 的3相中晚期出现早期后去极化(EAD),在30s 时,TAP上 EAD 的振幅为25.6±9.3mV,MAP 上的 EAD 振幅为3.4±1.3mV。EAD 表现为拖尾、平台、凸起三种不同形态。在两例猫中出现延迟性后去极化 DAD,其在 TAP 和 MAP上的振幅分别为13.0±5.3mV 和3.3±0.omV。MAP 上后去极化的形态与 TAP 极为相似。CsCl 的重复注射可诱发室性早搏、室性心动过速等多种心律失常,根据后去极化的发生与否以及后去极化和室性心搏的耦联间期的关系,可将心律失常分为两种类型:一种是由记录部位的后去极化引起的触发性心律失常;另一类可能由非记录部位的后去极化或其它机制引起。更多还原

【Abstract】 CsCl triggered activities in cat heart in vivo were studied by using floatingmicroelectrode and contact electrode to record transmembrane and monophasicaction potentials(TAP and MAP).Ten seconds after CsCl(0.5m mol/kg,i.v.),early afterdepolarization(EAD)appeared in the middle-later period of phase 3in both TAP and MAP.Thirty seconds after CsCl,the amplitude of TAP-EADwas 25.6±9.3 mV and that of MAP-EAD was 3.4±1.3 mV.The potentialchanges of the EADs could be divided into three kinds,i.e.the“tail”,the“pla-teau”and“peak”types.Delayed afterdepolarization(DADs)could also be indu-ced by CsCl in the phase 4 of the TAP and MAP in two cats.The amplitudes ofTAP-DAD and MAP-DAD were 13.0±5.3 mV and 3.3±0.6 mV respectively.The types of the afterdepolarizations in MAP were very similar to those in TAP.The ventricular extrasystole and/or tachycardias could be induced by repeatedinjections of CsCl.According to the occurrance of afterdepolarization(AD)and the relationship between the coupling interval of the AD and that of theventricular beat,two kinds of generation of arrhythmias were suggested,i.e.onetriggered by AD of the myocardium under the electrode and the other inducedby AD originating from the other sites of the myocardium.更多还原