When there is a sudden change from NSR to a sinus tachycardia with rate >150 bpm on telemetry, what is the likely differential and initial actions?

When there is a sudden change from NSR to a sinus tachycardia with rate >150 bpm on telemetry, what is the likely differential and initial actions?

• A. Supraventricular tachycardia such as AVNRT; treat with vagal maneuvers if stable.
• B. Atrial flutter with rapid conduction requiring immediate cardioversion.
• C. SVT or AVNRT; assess stability; check triggers; treat per protocol (vagal maneuvers, adenosine if guideline allows).
• D. Ventricular tachycardia requiring immediate defibrillation.

Answer: (C)