Gould L, Reddy R, Singh B K
Chest. 1979 Sep;76(3):310-33. doi: 10.1378/chest.76.3.310.
There is little information on the effects of methyldopa on the human conduction system. His bundle ECGs were obtained in 11 patients before and after the intravenous infusion of 100 mg of methyldopa. Antegrade refractory periods were obtained with the extrastimulus method. The significant results were as follows: the sinus rate was 71 +/- 4 beats per minute before, and 65 +/- 3 beats per minute after methyldopa (P less than 0.01). The mean A-H interval at a paced rate of 120 beats per minute was 113 +/- 14 msec before, and 135 +/- 18 msec after, methyldopa (P less than 0.05). The mean atrioventricular nodal functional refractory period was 430 +/- 23 msec before and 452 +/- 24 msec after methyldopa administration (P less than 0.001). The mean effective refractory period was 385 +/- 29 msec before, and 388 +/- 27 msec after methyldopa (P less than 0.01). The sinus node recovery time in the control state was 989 +/- 55 msec and 1102 +/- 66 msec after methyldopa infusion (P less than 0.05). Thus, methyldopa can impair conduction through the atrioventricular node and depress the sinus node.
关于甲基多巴对人体传导系统影响的信息较少。在11例患者静脉输注100mg甲基多巴前后进行了希氏束心电图检查。采用额外刺激法测定前向不应期。显著结果如下：甲基多巴用药前窦性心率为每分钟71±4次，用药后为每分钟65±3次（P<0.01）。以每分钟120次的起搏频率时，平均A-H间期在甲基多巴用药前为113±14毫秒，用药后为135±18毫秒（P<0.05）。房室结功能不应期平均值在甲基多巴用药前为430±23毫秒，用药后为452±24毫秒（P<0.001）。有效不应期平均值在甲基多巴用药前为385±29毫秒，用药后为388±27毫秒（P<0.01）。对照状态下窦房结恢复时间为989±55毫秒，甲基多巴输注后为1102±66毫秒（P<0.05）。因此，甲基多巴可损害房室结传导并抑制窦房结。
