Matsuo K, Shimizu W, Kurita T, Suyama K, Aihara N, Kamakura S, Shimomura K
Division of Cardiology, Department of Internal Medicine, National Cardiovascular Center, Osaka, Japan.
J Cardiovasc Electrophysiol. 1998 Jan;9(1):74-83. doi: 10.1111/j.1540-8167.1998.tb00869.x.
The role of increased dispersion of repolarization in the genesis of torsades de pointes in patients with long QT syndrome has been clarified, but its role in the genesis of idiopathic ventricular fibrillation (VF) is not yet known. To investigate the pathogenesis of VF, we recorded monophasic action potentials (MAPs) from two siblings (48- and 36-year-old males) with familial idiopathic VF.
The elder brother (patient 1) showed a late r' wave in lead V1 and ST segment elevation in leads V1 through V3. The younger brother (patient 2) had late r' waves and ST segment elevation in leads II, III, and aVF, and the configurations were very similar to those of patient 1. MAPs were recorded from several sites in the right ventricular (RV) and left ventricular (LV) endocardium during constant right atrial pacing. The repolarization time (RT) was defined as the sum of the activation time (AT) and action potential duration (APD) at 90% repolarization. In patient 1, marked prolongation of the AT (140 msec) and the RT (380 msec) was recorded in the RV septum of the outflow tract, and the RT dispersion was markedly increased (125 msec). In contrast, patient 2 showed prolongation of the AT (80 msec) and RT (310 msec), and fractionated electrograms in the RV floor of the inflow tract. The RT dispersion was also increased (80 msec). VF and nonsustained polymorphic ventricular tachycardia were induced by double premature stimulation in patients 1 and 2, respectively. Chronic amiodarone therapy decreased the RT dispersion and suppressed the induction of ventricular tachyarrhythmias in patient 2, although late r' waves and slight ST segment elevation were unmasked in leads V1 and V2.
Our data suggest that the increased dispersion of the RT, which was due mainly to a localized conduction delay in the RV, created an arrhythmogenic substrate in the two patients with familial idiopathic VF.
复极离散度增加在长QT综合征患者尖端扭转型室速发生中的作用已得到阐明，但其在特发性心室颤动（室颤）发生中的作用尚不清楚。为了研究室颤的发病机制，我们记录了两名患有家族性特发性室颤的兄弟（48岁和36岁男性）的单相动作电位（MAP）。
哥哥（患者1）在V1导联出现晚期r'波，V1至V3导联ST段抬高。弟弟（患者2）在II、III和aVF导联出现晚期r'波和ST段抬高，其形态与患者1非常相似。在右房持续起搏期间，从右心室（RV）和左心室（LV）心内膜的多个部位记录MAP。复极时间（RT）定义为激活时间（AT）与90%复极时动作电位持续时间（APD）之和。在患者1中，记录到流出道RV间隔处AT（140毫秒）和RT（380毫秒）明显延长，RT离散度明显增加（125毫秒）。相比之下，患者2表现为AT（80毫秒）和RT（310毫秒）延长，流入道RV底部出现碎裂电图。RT离散度也增加（80毫秒）。患者1和患者2分别通过双重过早刺激诱发了室颤和非持续性多形性室性心动过速。慢性胺碘酮治疗降低了患者2的RT离散度并抑制了室性心律失常的诱发，尽管V1和V2导联出现了晚期r'波和轻微ST段抬高。
我们的数据表明，主要由于RV局部传导延迟导致的RT离散度增加，在两名家族性特发性室颤患者中形成了致心律失常基质。
