Early out-of-hospital lidocaine administration decreases the incidence of primary ventricular fibrillation in acute myocardial infarction.

This study was designed to assess the effectiveness of early prehospital intravenous administration of lidocaine in preventing primary ventricular fibrillation (PVF) in patients with suspected acute myocardial infarction (AMI). Sixty patients with suspected AMI, seen by the Mobile Coronary Care Unit (MCCU) of Florence, were randomly allocated at home to treatment with lidocaine (bolus i.v. of 1 mg/kg, followed by an infusion of 4 mg/min) or placebo (infusion of saline at a rate of 1 mL/min), respectively. The lidocaine group (27 patients) and the control group (33 patients) were not significantly different in age, clinical condition, or time of randomization. The diagnosis of AMI was confirmed in all 60 patients during the hospital stay. Ventricular fibrillation (VF) occurred in 5 patients in the control group in comparison to none in the lidocaine group (P < 0.05). Three patients experienced VF at home and were successfully resuscitated by an MCCU cardiologist. In another two patients, VF occurred during the first 4 hours after onset of symptoms. No major side effects were observed after the infusion of lidocaine. Our findings support the effectiveness of the prophylactic administration of lidocaine in preventing PVF in the prehospital phase of AMI and suggest that the drug can be safely administered in this setting by prehospital personnel.