In unstable pediatric patients with narrow complex tachycardia (≤0.11 seconds), what is the initial recommended treatment?

• A. Adenosine
• B. Synchronized Cardioversion
• C. Etomidate 0.15 mg/kg IV/IO
• D. Magnesium Sulfate 25 mg/kg IV/IO

Answer: (A)

In unstable pediatric patients with a narrow complex tachycardia, the priority is rapid stabilization of perfusion. A synchronized cardioversion delivers a controlled shock timed to the heartbeat, quickly terminating the tachycardia and restoring effective cardiac output, which is essential when the patient’s condition is deteriorating. The usual initial energy dose is 0.5 to 1 joule per kilogram, with a higher dose (about 2 J/kg) if needed. Adenosine is typically used for stable narrow-complex SVT to terminate AV nodal–dependent tachycardias and to help confirm the rhythm, but it does not reliably improve hemodynamics in an unstable patient and can be ineffective or unsafe if the rhythm isn’t AV nodal–dependent. Once the patient is stabilized, further management can be guided by rhythm and stability.