In stable tachycardia with wide QRS ≥ 0.12 seconds and regular monomorphic VT, what is the recommended initial treatment?

• A. AMIODARONE 150 mg in 50 mL NS over 10 mins
• B. Synchronized Cardioversion
• C. Defibrillate
• D. Magnesium sulfate 2 g IV/IO in 50 mL NS over 10 min

Answer: (A)

In a stable patient with tachycardia that is wide (≥0.12 s) and monomorphic, the rhythm is ventricular tachycardia rather than a supraventricular rhythm with aberrancy. The best first step is to give an antiarrhythmic medication to restore rhythm without relying on electricity. Amiodarone given IV, 150 mg over 10 minutes, is preferred because it effectively terminates VT and is well tolerated in hemodynamically stable patients, with the option to continue a maintenance infusion if needed.

Defibrillation or synchronized cardioversion is reserved for unstable VT or VT with signs of poor perfusion. Magnesium sulfate is specifically for torsades de pointes or contexts with magnesium deficiency, not regular monomorphic VT. So the initial, best choice in this scenario is IV amiodarone.