劳卡胺对豚鼠离体右心室壁缺血再灌注性心律失常的影响

目的　探讨劳卡胺对折返激动有关心律失常的对抗作用及其机制。方法　修改的Ferrier豚鼠离体右心室壁缺血 再灌注心律失常模型 ,即标本经模拟缺血台氏液灌流 1 0min ,而后用正常台氏液行再灌注。结果　劳卡胺分别在 0 62mg/L、1 2 5mg/L及 2 50mg/L剂量时使缺血性心律失常发生率轻度降低 (P >0 0 5) ,后 2种剂量使再灌注早期心律失常发生率明显降低 (P <0 0 5) ;降低心律失常发生率同时可提高心内膜下心室肌兴奋阈 ,延长心内、外膜下心室肌细胞动作电位时程 ,延迟或部分延迟冲动跨壁传导时间。结论　劳卡胺可提高心肌细胞兴奋阀 ,延长动作电位时程 ,延迟跨壁传导 ,这可能是其抗心律失常特别是折返型心律失常的电生理学基础。

Effect of Lorcainide on right ventricular free wall ischemia-reperfusion arrhythmia of isolated guinea pig

Objective To investigate the effect of lorcainide on reentryrelated arrhythmias and its electrophysiological mechanisms.Methods Using modified Ferriers ischemia-reperfusion induced arrhythmic model in isolated guinea pig right ventricular wall.In this model,the preparation was superfused with modified ischemic Tyrodes solution for 10 min then reperfusioned with normal Tyrodes solution.Results Lorcainide at concentration of 0.62mg/L,1.25mg/L and 2.50mg/L had a tendency of decreasing the incidence of arrhythmia during ischemia (P＞0.05),and at 1.25mg/L and 2.50mg/L significantly decreased incidence of arrhythmia during early reperfusion (P＜0.05).Its antiarrhythmic effect was accompanied with elevation of subendocardial threshold,significant abbreviation of action potential duratin (APD) in subendocardium and subepicardium,and complete or partly delay of transmural conduction time of pulses (CTtrans or CTepi). Conclusion Lorcainide could elivate threshold,prolong APD and delay CTepi,and this may be its electrophysiologic basic of antiarrhythmic mechanism.