目的探讨氟卡尼对兔左室心肌收缩力及心电活动的影响。方法采用冠状动脉灌注左室楔形组织块标本,分别施加基础刺激周长(BCL)为2 000,1 000,500 m s的刺激。同步记录用药前和0.3,1,3,6,10μmol/L氟卡尼使用后心肌收缩力和QRS波时限、QT...目的探讨氟卡尼对兔左室心肌收缩力及心电活动的影响。方法采用冠状动脉灌注左室楔形组织块标本,分别施加基础刺激周长(BCL)为2 000,1 000,500 m s的刺激。同步记录用药前和0.3,1,3,6,10μmol/L氟卡尼使用后心肌收缩力和QRS波时限、QT间期、T波峰-未间期(Tp-e)间期及Tp-e/QT。结果在本实验刺激的频率范围内,心肌收缩力随频率加快而增强,但随氟卡尼浓度的升高,心肌收缩力逐渐减弱。但当BCL为500 m s时,10μmol/L氟卡尼致收缩力反较BCL 1000 m s时降低。用药前QRS波在不同刺激频率下保持稳定,但随着氟卡尼浓度的升高QRS波明显增宽,呈现明显的频率依赖性特征,加快刺激频率10μmol/L氟卡尼可引起QRS波时程电交替,并可引起室性心动过速、心室颤动。氟卡尼未引起QT间期、Tp-e间期及QT/Tp-e明显改变。结论氟卡尼明显抑制电活动传导和反转心肌收缩力随频率加快而增强的效应,易诱发心律失常。展开更多
Aims This study compared the efficacy and safety of intravenous flecain ide and ibutilide for immediate cardioversion of atrial fibrillation (AF). Methods and results We conducted a prospective, randomised trial, incl...Aims This study compared the efficacy and safety of intravenous flecain ide and ibutilide for immediate cardioversion of atrial fibrillation (AF). Methods and results We conducted a prospective, randomised trial, including 207 patients wit h AF of recent onset (≤48 h). Flecainide was given over 20 min at a dose of 2 m g/kg body weight (maximum 200 mg), ibutilide was infused at a dose of 1 mg (or 0 .01 mg/kg if less than 60 kg) over 10 min, followed by a 10 min observation peri od and an identical second dose if AF did not convert to sinus rhythm (SR). Trea tment was considered successful if SR occurred within 90 min of starting medicat ion. The conversion rates were 56.4%in patients given flecainide and 50.0%in p atients given ibutilide (P=0.34). Multivariate analysis revealed that a lower ag e for women independently increased the probability of conversion. None of the o ther variables, including left atrial size, left ventricular systolic function, presence of left ventricular hypertrophy, plasma levels of potassium or magnesiu m at baseline, or concomitant use of digoxin, beta-blocker, diltiazem or verapa mil were predictors of conversion. The frequency of adverse events was comparabl e in the two treatment groups. Conclusions There was no significant difference i n the cardioversion efficacy or in the risk of adverse events between flecainide and ibutilide in patients with AF of recent onset. In patients without contrain dications to both medications, the physician’s choice has to be governed by oth er factors.展开更多
文摘目的探讨氟卡尼对兔左室心肌收缩力及心电活动的影响。方法采用冠状动脉灌注左室楔形组织块标本,分别施加基础刺激周长(BCL)为2 000,1 000,500 m s的刺激。同步记录用药前和0.3,1,3,6,10μmol/L氟卡尼使用后心肌收缩力和QRS波时限、QT间期、T波峰-未间期(Tp-e)间期及Tp-e/QT。结果在本实验刺激的频率范围内,心肌收缩力随频率加快而增强,但随氟卡尼浓度的升高,心肌收缩力逐渐减弱。但当BCL为500 m s时,10μmol/L氟卡尼致收缩力反较BCL 1000 m s时降低。用药前QRS波在不同刺激频率下保持稳定,但随着氟卡尼浓度的升高QRS波明显增宽,呈现明显的频率依赖性特征,加快刺激频率10μmol/L氟卡尼可引起QRS波时程电交替,并可引起室性心动过速、心室颤动。氟卡尼未引起QT间期、Tp-e间期及QT/Tp-e明显改变。结论氟卡尼明显抑制电活动传导和反转心肌收缩力随频率加快而增强的效应,易诱发心律失常。
文摘Aims This study compared the efficacy and safety of intravenous flecain ide and ibutilide for immediate cardioversion of atrial fibrillation (AF). Methods and results We conducted a prospective, randomised trial, including 207 patients wit h AF of recent onset (≤48 h). Flecainide was given over 20 min at a dose of 2 m g/kg body weight (maximum 200 mg), ibutilide was infused at a dose of 1 mg (or 0 .01 mg/kg if less than 60 kg) over 10 min, followed by a 10 min observation peri od and an identical second dose if AF did not convert to sinus rhythm (SR). Trea tment was considered successful if SR occurred within 90 min of starting medicat ion. The conversion rates were 56.4%in patients given flecainide and 50.0%in p atients given ibutilide (P=0.34). Multivariate analysis revealed that a lower ag e for women independently increased the probability of conversion. None of the o ther variables, including left atrial size, left ventricular systolic function, presence of left ventricular hypertrophy, plasma levels of potassium or magnesiu m at baseline, or concomitant use of digoxin, beta-blocker, diltiazem or verapa mil were predictors of conversion. The frequency of adverse events was comparabl e in the two treatment groups. Conclusions There was no significant difference i n the cardioversion efficacy or in the risk of adverse events between flecainide and ibutilide in patients with AF of recent onset. In patients without contrain dications to both medications, the physician’s choice has to be governed by oth er factors.
