First-line antiarrhythmic for shock-refractory VF/pVT and its dose?

First-line antiarrhythmic for shock-refractory VF/pVT and its dose?

• A. Amiodarone 300 mg IV bolus; if persists, 150 mg IV
• B. Lidocaine 1-1.5 mg/kg IV bolus; additional doses up to 3 mg/kg total
• C. Magnesium sulfate 1-2 g IV push
• D. Sotalol 100 mg IV

Answer: (A)

In shock-refractory ventricular fibrillation or pulseless VT, the antiarrhythmic given first is amiodarone because it reliably suppresses recurrent VT/VF after defibrillation attempts and improves rhythm conversion. The recommended dose is a 300 mg intravenous bolus as soon as defibrillation has failed; if the rhythm persists, a second bolus of 150 mg IV can be given (for a possible total of 450 mg in the early management). Lidocaine is a backup option if amiodarone isn’t available, but amiodarone has stronger evidence for this scenario. Magnesium is reserved for torsades de pointes or magnesium deficiency, and sotalol is not used acutely in this setting due to proarrhythmic risk.

In shock-refractory ventricular fibrillation or pulseless VT, the antiarrhythmic given first is amiodarone because it reliably suppresses recurrent VT/VF after defibrillation attempts and improves rhythm conversion. The recommended dose is a 300 mg intravenous bolus as soon as defibrillation has failed; if the rhythm persists, a second bolus of 150 mg IV can be given (for a possible total of 450 mg in the early management). Lidocaine is a backup option if amiodarone isn’t available, but amiodarone has stronger evidence for this scenario. Magnesium is reserved for torsades de pointes or magnesium deficiency, and sotalol is not used acutely in this setting due to proarrhythmic risk.