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本实验观察了开胸麻醉家兔急性心肌缺血时的不应期改变。用吸引电极记录的单相动作电位(MAP)确定机能不应期(FRP)及 FRP 超过 MAP 复极90%时程(MAPD_(90))的复极后不应性(PRR)。阻断冠脉左室支以后,缺血区不应期表现出两种完全不同的变化:缺血中心区不应期延长并超过 MAPD_(90),出现 PRR;缺血周边区不应期则通常较对照缩短。利用自体颈总动脉的动脉血进行灌流的兔心实验表明,当100%阻断灌流血液时,缺血中心区出现PRR,但是当50%阻断时,同一部位心肌的不应期却表现为缩短。上述结果提示:PRR 是在严重心肌缺血情况下出现的。同一时刻测定缺血中心区、周边区和非缺血区的功能不应期,结果表明,冠脉阻断后不应期离散程度的明显增大是与当时 PRR 的出现密切相关的。因此,PRR 的存在可以认为是造成急性心肌缺血时不应期离散的重要原因,而后者一般认为是异致折返性心律失常的重要因素。
This experiment observed the thoracic anesthesia rabbits acute myocardial ischemia should not change. The single-phase action potential (MAP) recorded with the aspiration electrode was used to determine the post-impulse repression (PRR) of the functional refractory period (FRP) and the FRP over the MAP repolarization 90% (MAPD_ (90)). After blocking the left ventricular branch of coronary artery, the refractory period showed two completely different changes: ischemic center should not extend beyond the MAPD 90, PRR occurred; Usually shorter than the control. Rabbit heart perfusion using arterial blood from the common carotid artery showed that when 100% blocked perfusion, PRR occurred in the ischemic center, but when 50% blocked, the refractory period in the same site was shorten. The above results suggest that PRR occurs in severe myocardial ischemia. Simultaneous determination of the functional refractory period of ischemic center, peripheral area and non-ischemic area at the same time showed that the significant increase of refractory period dispersion after coronary occlusion was closely related to the occurrence of PRR. Therefore, the presence of PRR can be considered to cause acute myocardial ischemia refractory refractory period an important reason, while the latter is generally considered a key factor for allo-reentretic arrhythmia.