Metoprolol Contributed Antiarrhythmic Effect Of Amiodarone

Objective: To study the influence of antiarrhythmic effects of pre-intragastric administration Metoprolol to Amiodarone on ventricular arrhythmias. To provide experimental evidence for clinical administration .Methods: Intragastric administration different dose of Metoprolol for two weeks in rats,apply Amiodaroneon by vein after withdrawal Metoprolol for five half-decay period, adopt arrhythmia model of BaCl2 or Aconitine and observe ventricular arrhythmias duration, To observe the influence of antiarrhythmic effects of different dose of Metoprolol to Amiodarone on two arrhythmic model. (1)To BaCl2 model:80 rat, to divide equally and probabilisticly into eight groups:①normal sodium group;②3.125mg/kg Metoprolol group;③6.25mg/kg Metoprolol group;④12.5mg/kg Metoprolol group;⑤Amiodarone group;⑥3.125mg/kg Met+Ami group;⑦6.25mg/kg Met+Ami group;⑧12.5mg/kg Met+Ami group. Intragastric administration Metoprolol for two weeks after five half-decay period , iv Amiodarone and iv BaCl2 five minute late . observe theⅡlead ECG continuously by multichannel system of physiology information ( RM-6240-C-type), memorize and analyze duration of arrhythmias.(2)To aconitine model:80 rat, to divide equally and probabilisticly into eight groups:①normal sodium group;②3.125mg/kg Metoprolol group;③6.25mg/kg Metoprolol group;④12.5mg/kg Metoprolol group;⑤Amiodarone group;⑥3.125mg/kg Met+Ami group;⑦6.25mg/kg Met+Ami group;⑧12.5mg/kg Met+Ami group. Intragastric administration for two weeks after five half-decay period , iv Amiodarone and iv aconitine five minute late . observe theⅡlead ECG continuously by multichannel system of physiology information( RM-6240-C-type), memorize and analyze duration of arrhythmias.Results:(1)To BaCl2 arrhythmia model,intragastric administration Metoprolol can reduced the duration,but distinction have not statistical significance(,P>0.05);With the dose increasing of Metoprolol,Amiodarone shorted the duration of arrhythmias(P < 0.05).Reflect the effect of Amiodarone on antiarrhythmias were markedly contributed by Metoprolol, the contributed effect have a quality of dose dependent.(2)To aconitine model:intragastric administration Metoprolol reduced the duration of ventricular arrhythmias, no statistical significance,(P>0.05);But with dose increasing of Metoprolol,Amiodarone reduced the duration(P < 0.05).Conclusion:①the effect of Amiodarone on antiarrhythmias were contributed by intragastric administration Metoprolol.②the contributed effect have quality of dose dependent.③Metoprolol can contribute antiarrhythmic effect of Amiodarone on different model.