地尔硫对人体房室结电生理特性的频率依赖性作用

目的评价频率对地尔硫心脏电生理作用的影响。方法对17例患者进行电生理检查，分析应用地尔硫前后在不同频率情况下房室结的电生理变化。结果地尔硫不影响窦性心律周长、窦房结恢复时间、HV间期，但房室结文氏周长由312.2±18.6ms延长到408.3±17.5ms(P＜0.01)。在慢频率心房起搏时，地尔硫使房室结有效不应期(AVNERP)和AH间期延长，延长量分别为44.2±10.8ms和19.2±6.7ms。在快频率心房起搏时，AVNERP和AH延长更为显著，分别为91.7±14ms和47.5±10.6ms(P＜0.01，与慢频率相比)。地尔硫延长AVNERP的程度大于AH间期，在快频率时该作用更为明显。结论地尔硫对人体房室结功能影响具有快频率依赖性特点，这种作用使其在心动过速时选择性抑制房室结。

Rate-Dependent Effects of Diltiazem on Human Atrioventricular Nodal Properties

Objective:To evaluate the importance of heart rate in modulating the electrophysiological effects of diltiazem in human.　　Methods:Electrophysiological parameters of atrioventricular node were analysed at multiple atrial rates before and after administration of diltiazem.　　Results:Electrophysiological studies were performed in 17 patients.Sinus cycle length,sinus node recovery time(SNRT) and HV interval were unaffected by diltiazem infusion,but wenckebach cycle length(WCL) were prolonged from 312.2±18.6 ms to 408.3±17.5 ms (p＜0.01).During atrial paced rhythm at long cycle length,diltiazem caused increase in A-V nodal effective refractory period(AVNERP) and AH(44.2±10.8 ms and 19.2±6.7 ms,respectively).Drug effects were far greater at short cycle length,91.7±14.0 ms for AVNERP and 47.5±10.6 ms for AH (p＜0.01 versus values at long cycle length).Effects of diltiazem on AVNERP exceeded those on AH.　　Conclusion:Diltiazem depresses human atrioventricular nodal function in frequency-dependent manner,these effects lead to highly selective depression of AV nodal function during tachycardias.