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| Background: Ventricular fibrillation (VF) is one of the most common reasons for sudden cardiac death. Many events may prevent paramedics from timely arrival to treat cardiac events. In the present study, we compared lidocaine and amiodarone in terms of ameliorating prolonged VF.
Methods: After 12 min of untreated VF, 21 dogs received 2 min of cardiopulmonary resuscitation (CPR) followed by immediate defibrillation. When the first defibrillation failed, animals were randomly assigned to 3 groups (n=7 for every group) for rapid treatment with intravenous lidocaine (1.5 mg/kg), amiodarone (5 mg/kg) or placebo (5 ml normal saline). Prolonged QT interval was defined as the difference between basic QT interval and post-resuscitation QT interval. Aortic and right atrial pressures were monitored continuously. Coronary perfusion pressure after drug administration was calculated at mid-diastole by subtracting right atrial diastolic pressure from aortic diastolic pressure.
Results: The 3 groups did not differ in survival rate, hemodynamic measurements after drug administration, or heart rate, PR interval or QRS complex (p=0.074, 0.077 and 0.415, respectively). The amiodarone and lidocaine groups differed significantly in prolonged QT interval (420.0±192.2 vs. 234.0±19.5 ms, p=0.036). One case of atypical torsades de pointes was found in the amiodarone group. Three, 5, and 3 dogs in the amiodarone, lidocaine and placebo groups, respectively, survived for more than 2 hr. Conclusions: In the prolonged VF model, amiodarone and lidocaine had a similar effect on terminating VF, hemodynamics and survival rate. Lidocaine may be safer than amiodarone in terminating refractory VF. |
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| Keywords:sudden cardiac death; prolonged ventricular fibrillation; amiodarone; lidocaine |
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