氟卡尼在豚鼠左房的电生理作用

Electrophysiologic Effects of Flecainide in Guinea Pig Left Atrium

本文用电生理技术，在离体豚鼠左房对氟卡尼电生理特性进行了研究。氟卡尼能剂量和频率依赖性地抑制动作电位零相最大上升速率（Ｖｍａｘ），动作电位幅度（ＡＰＭ）和超射（ＯＳ）。研究发现氟卡尼在较高频率刺激下（２Ｈｚ，３．３Ｈｚ）趋向于延长动作电位时程，具有时间和频率依赖性。这对缺血和再灌注诱发的心律失常具有重要意义。在不同频率刺激下，氟卡尼能使被缩短的动作电位时程趋向于正常并具频率依赖性。这些可能与其治疗房性心律失常有关。

The electrophysiologic properties of flecainide (FLC),a new potential antiarrhythmic agent, are poorly defined.In this studies,they were investigated by conventionai microelectrode technique in isotated quinea pig left atrial muscles.The concentration of FLC used were 0.1,0.3,1,3,10and 30μmol/L.FLC produced a concentration-dependent decrease in maximal rate of rise of phase of the action potential (Vmax),action potential amplitude(AMP)and overshoot(OS). Vmax was reduced by 80.1±9.4%(P>0.05)after 0.3μmol/L FLC,by 68.2±7.8% (P<0.05) after 3.0μmol/L FLC and by 57.8±4.8% (P<0.01) after 10.0 μmol/L FLC at stim ulation rare of 1 Hz. The corresponding values of Vmax for 3 Hz 95.3±2.2% (0.3μmul/L FLC,P>0.05),69.2±9.7%(3μmol/L FLC,P<0.05) and 47. 3±11.5%(10μmol/L FLC,P<0.01).The Vmax was decreased markedly by 1.0μmul/L PLC in the stimulation rates of 0.2,0 5,1,2 and 3.3 Hz,their values were 92.3±2.2%(P<0.05),89.2±2.6% (P<0.05),89.4±3.7%(P<0.05),89.1±1.9% (P<0.01)and 83.8±4.1% (P<0.01).The depression of Vmax by FLC was dose-and frequency-dependence, this may be a important cause of FLC in the supperision of atrialarrhythmias. It was found that FLC at the stimulation frequencies of 2 Hz and 3.3 Hz tended to lengthen the APD with time and dose-dependence in quinea pig left atrium,which is very bene ficial for the patients who suffered from the arrythmias evoked by ischemia and reperfusion. It was also proved that FLC at the different stimulation frequencies could recovered the APD which have been shortened towards normal with a frequency-dependence,this may be another reason of the drug in the inhibition of atrial arrhythmi as.The slow response current might be influenced by 0.1 to 30μmol/L FLC in guinea pig left atrium only at the stimulation frequencies of 2 Hz and 3 Hz,5 to 15 minutes followtng the agent.