For a hemodynamically stable patient with sustained VT lasting more than 30 seconds, which of the following is considered first-line therapy?

• A. Synchronized cardioversion
• B. Defibrillation
• C. Class I or III anti-arrhythmics (lidocaine, amiodarone)
• D. Observation

Answer: (C)

When a patient with sustained ventricular tachycardia is hemodynamically stable, the first move is to treat with an antiarrhythmic drug to terminate the rhythm and restore a regular heartbeat. Amiodarone, a class III antiarrhythmic, is typically preferred because it works across a broad range of VT etiologies and is effective in patients with structural heart disease. Lidocaine, a class IB drug, is also an option, especially in ischemic VT, but amiodarone generally provides reliable conversion with a favorable safety profile in stable patients. These medications slow ventricular conduction and prolong refractoriness, suppressing the abnormal circuits or foci driving the VT.

Defibrillation is reserved for pulseless VT or when the patient loses stability, and synchronized cardioversion is used if instability develops, since those scenarios require immediate energy delivery to restore circulation. Observation without treatment would allow the tachycardia to persist and risk deterioration.