Abstract: AimTo investigate the effects of imidapril (IMI) on effective refractory period (ERP) and sodium current (I_Na) of myocytes in ventricular noninfarction zone of healed myocardial infarction (HMI) in rabbit models. MethodsRabbits with left coronary artery ligation were prepared and IMI (0625 mg·kg^-1·d^-1, 8 weeks) was orally administered. The ERP and sodium current were recorded. ResultsThe ERP in HMI heart was prolonged. The ERP in IMI group was lower significantly than that of HMI group. The I_Na density of myocyte in HMI ventricle decreased obviously. V_1/2 of steady state inactivation of I_Na shifted to hyperpolarization, and time constant (τ) of recovery from inactivation in HMI ventricular myocyte was longer than that of sham ventricular myocyte. I_Na density in IMI group increased markedly as compared with that of HMI group. ConclusionIMI was shown to reverse the abnormal prolongation of ERP in rabbit heart with the HMI and increase I_Na density. It may be the mechanism of IMI preventing against antiarrhythmia in healed myocardical infarction.