Asao Y, Matsumoto M, Wake M, Hirai Y
Department of Anesthesia, Kobe West Municipal Hospital, Japan.
Masui. 1996 Apr;45(4):483-6.
A 65-year-old woman with ovarian tumor was scheduled for abdominal total hysterectomy and bilateral adnexectomy under epidural anesthesia. Preoperative examinations revealed no abnormalities including ECG. Twenty minites after the epidural injection of mepivacaine, widened QRS complexes, which were diagnosed as complete left bundle branch block (CLBBB) later, appeared on ECG. At that time, heart rate (HR) was 150.min-1. CLBBB disappeared when HR decreased to 110.min-1 following the administration of pindolol and verapamil. The operation was postponed. Exercise-treated ECG showed neither CLBBB nor ischemic change even when HR increased to 160.min-1. Two weeks later the operation was attempted again. CLBBB appeared again twenty minites after the epidural injection of mepivacaine. The CLBBB disappeared 5 minites after the induction of general anesthesia when HR decreased to 100.min-1. The operation was performed uneventfully. The effective refractory period (ERP) is shortened with the increase in HR, but the shortning of ERP varies in different part of the cardiac conduction system. In tachycardia, ERP of left bundle branch is longer than that of right one. Because the cardiac conduction system is depressed by local anesthetics, it is speculated that ERP of left bundle branch is elongated further by mepivacaine and CLBBB appeared in this case.
一名65岁患有卵巢肿瘤的女性计划在硬膜外麻醉下行腹式全子宫切除术和双侧附件切除术。术前检查包括心电图均未发现异常。硬膜外注射甲哌卡因20分钟后，心电图上出现QRS波群增宽，后来被诊断为完全性左束支传导阻滞（CLBBB）。当时，心率（HR）为150次/分钟。给予吲哚洛尔和维拉帕米后，心率降至110次/分钟时，CLBBB消失。手术推迟。运动试验心电图显示即使心率增至160次/分钟时也未出现CLBBB及缺血性改变。两周后再次尝试手术。硬膜外注射甲哌卡因20分钟后CLBBB再次出现。全麻诱导后5分钟，心率降至100次/分钟时CLBBB消失。手术顺利进行。有效不应期（ERP）随心率增加而缩短，但ERP在心脏传导系统不同部位的缩短情况有所不同。在心动过速时，左束支的ERP长于右束支。由于心脏传导系统受局部麻醉药抑制，推测甲哌卡因进一步延长了左束支的ERP，导致本例出现CLBBB。
