Gepstein L, Hayam G, Ben-Haim S A
Cardiovascular System Laboratory, the Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
Circulation. 1997 Dec 2;96(11):4036-43. doi: 10.1161/01.cir.96.11.4036.
While abnormalities of activation and repolarization play an important role in arrhythmogenesis, little information is available on the interaction between their spatial dispersions in the heart. This study examined the effects of activation spread on the spatial distribution of the repolarization properties during different depolarization patterns.
Left ventricular (LV) endocardial activation and repolarization patterns were mapped in 13 healthy pigs. LV local activation, repolarization, and activation-recovery interval (ARI) times were determined from the intracardiac unipolar electrograms, color-coded, and superimposed on a three-dimensional anatomic map of the ventricle generated with a nonfluoroscopic mapping system. ARI values correlated with the duration of monophasic activation potential recorded from onset of activation to time of 90% repolarization (r=.97, P<.01). Activation time range of the left ventricle was 42+/-5 ms (mean+/-SEM) during sinus rhythm and 54+/-5 ms during right ventricular septal pacing. ARI inversely correlated with the corresponding activation times during both sinus (r2=.76+/-.03) and paced (r2=.77+/-.02) rhythms. The longest ARIs were located at the sites of earliest activation and shortest at the latest activation areas, with gradual shortening between them.
The spatial distribution of repolarization is dependent on the activation pattern. Repolarization dispersion in the healthy swine heart is relatively small as the result of tight coupling of the action potential duration to the activation process, assigning longer ARIs to sites activated earlier. This coupling reduces global and regional dispersion of repolarization and may serve as an important antiarrhythmic mechanism present in normal myocardium.
虽然激活和复极化异常在心律失常的发生中起重要作用，但关于它们在心脏中的空间离散之间的相互作用的信息却很少。本研究探讨了在不同去极化模式下激活传播对复极化特性空间分布的影响。
在13只健康猪中绘制左心室（LV）心内膜激活和复极化模式。从心内单极电图确定LV局部激活、复极化和激活-恢复间隔（ARI）时间，进行颜色编码，并叠加在用非荧光映射系统生成的心室三维解剖图上。ARI值与从激活开始到90%复极化时间记录的单相动作电位持续时间相关（r = 0.97，P < 0.01）。窦性心律时左心室的激活时间范围为42±5毫秒（平均值±标准误），右心室间隔起搏时为54±5毫秒。在窦性（r2 = 0.76±0.03）和起搏（r2 = 0.77±0.02）心律期间，ARI与相应的激活时间呈负相关。最长的ARI位于最早激活的部位，最短的位于最晚激活的区域，两者之间逐渐缩短。
复极化的空间分布取决于激活模式。由于动作电位持续时间与激活过程紧密耦合，健康猪心脏中的复极离散相对较小，使较早激活的部位具有更长的ARI。这种耦合减少了复极化的整体和区域离散，可能是正常心肌中存在的一种重要抗心律失常机制。
