伊布利特对人体心房与心室的电生理作用及其频率依赖性研究

目的探讨伊布利特对人体心房、心室的电生理作用及其频率依赖性。方法25例射频消融术后患者于静脉推注伊布利特（0．0167mg／kg）前后测定两种起搏周长（PCL，400ms与600ms）时的右心房、左心房及右心室的有效不应期（RA-ERP、LA-ERP及RV-ERP），其中通过起搏冠状静脉窦远端问接起搏左心房。结果（1）明显延长RA-ERP（PCL=400ms时，由215．20ms延长至259．60ms，P〈0．001；PCL=600ms时，由231．20ms延长至281．20ms，P〈0．001）；（2）明显延长LA-ERP（PCL=400ms时，由216．60ms延长至247．60ms，P〈0．001；PCL=600ms时，由226.40ms延长至262．40ms，P〈0．001）；（3）明显延长RV-ERP（PCL=400ms时，由219．60ms延长至249．60ms，P〈0．001；PCL=600ms时，由233．20ms延长至268.20ms，P〈0．001）；（4）PCL=400ms与PCL=600ms比较，对RA-ERP、LA-ERP及RV-ERP延长程度均差异无统计学意义（P〉0．05）；（5）明显延长QT与QTc间期，其中QTc由384．36ms延长至450．66ms（P〈0．001），对窦性心率〈82次／min与≥82次／min患者的QT与QTc延长程度差异无统计学意义（P〉0．05）。结论伊布利特可明显延长RA-ERP、LA-ERP、RV-ERP及QT、QTc，而且这些电生理作用无频率依赖性。

The study of electrophysiological effect of ibutilide on human atrium and ventricle and the rate-dependent effect

Objective We studied the rate-dependent effect of ibutilide on the electrophysilolgical parameters of human atrium and ventricle to explore the mechanism of ibutilide in atrial fibrillation conversion.Methods Effective refractory period(ERP)of left atrium (LA) right atrium (RA) and right ventride (RV) during pacing at cycle length (PCL) of 600 ms and 400 ms in 25 patients who underwent radio frequency cather ablation successfully were measured before and after intravenous administration of ibutilide (0.0167 mg/kg).Results Ibutilide prolonged RA-ERP by 50.00 ms (P<0.001) at PCL of 600 ms and 44.40 ms(P<0.001)at PCL of 400 ms,LA-ERP by 36.00 ms (P<0.001) at PCL of 600 ms and 31.60 ms (P<0.001) at PCL of 400 ms,RV-ERP by 35.00 ms (P<0.001) at PCL 600 ms of and by 30.00 ms(P<0.001) at PCL 400 ms.It also prolonged QT and QTc by 64.58 ms and 67.26 ms in patients whose heart rates over 82 bpm and by 72.31 ms and 65.41 ms in those under 82 bpm (P<0.05).Conclusions Ibutilide prolonged RA-ERPLA-ERP and RV-ERP of human without reverse rate-dependency.This might be the important mechanism for high efficacy of ibutilide for termination of atrial-flutter and fibrillation.