氟卡胺和AARL对豚鼠右房电生理特性的作用

Electrophysiological Properties of Flecainide and AARL in Guinea Pig Right Atria

氟卡胺和AARL具有预防和治疗房颤的作用,然而其对心房的电生理特性仍不清楚。本文观察了等摩尔的氟卡胺和AARL对豚鼠右房动作电位等指标的作用。二者均剂量依赖性地抑制Vmax,氟卡胺的作用强于AARL。氟卡胺30μmol/L分别使APD_(90)增加至给药前的152±11.5%((?)±s(?),P<0.01),APD_(50)为140.6±15.2%,(P<0.05),APD_(20)为159.9±17.8%(P<O.05);AARL1至3μmol/L明显缩短豚鼠右房的APD,而30μmol/L使APD趋向于正常,它们的APD_(90)为106.3±11.2%(P>0.05),APD_(50)为100.5±13.2%(P>0.05),APD_(20)112.4±18.4%(P>0.05)。氟卡胺和AARL抗房颤作用机制与二者抑制Vmax及对APD作用有关。

Flecainide (Fie) and AARL [S-(1)-6-Chloro-2, 2-dime-thy1-1'-[3-(4-hydroxy-piperizino) propyl] spiro [chroman-4, 4'-imidzolidine]-2'5'-dione hydrochloride] are effective in the prevention and termination of atrial fibrillation, but the electrophysiological properties of this action in guinea pig right atria are unknown. To gain insight into potetial cellular mechanisms, we evaluated the response of guinea pig right atrial action potentials to equimolar concentrations of Fle and AARL. Both compounss reduced Vmax more as the dose increased bat the effect of Fle on Vmax slightly was potent than that of AARL. In contrast to the changes in Vmax, the drug-induced alternations in action potential duration showed differences for the both drugs. Fle (30μmol/L) increased action potential duration at 90% repolarization (APD_(90)) to 152±11.5% (mean±s_x~, ··P<0.01), APD_(50) to 140.6±15.2% (·P<0.05) and APD_(20) to 159.9±17.8% (·P<0.05) at a cycle length of 1000 msec; AARL (1 to 3μmol/L) significantly shortened the APD in guinea pig right atria, but AARL (30μmol/L) tended to restore the APD towards normal, their values APD_(90) were 106.3±11.2% (P>0.05), APD_(50) 100.5±13.2% (P>0.05) and APD_(20) 112.4±18.4% (P>0.05). The salutary response of atrial fibrillation to Fle and AARL may be due to the depressant ac ion of Vmax and the recovering of drug action on APD.