In a wide-complex tachycardia with a pulse where ventricular tachycardia is suspected, what is a reasonable first-line drug?

• A. Lidocaine
• B. Amiodarone
• C. Metoprolol
• D. Adenosine

Answer: (B)

When you have a wide-complex tachycardia with a pulse and VT is suspected, you want an antiarrhythmic that is broadly effective against VT and safe in patients with heart disease. Amiodarone fits this role well because it acts on multiple electrical targets—blocking potassium channels to prolong repolarization, as well as affecting sodium, calcium channels, and beta-adrenergic receptors. This combination helps terminate VT and prevent recurrence without causing as much drop in blood pressure as some other drugs. It’s effective for VT regardless of whether there’s structural heart disease, which is common in wide-complex tachycardia.

Adenosine is not useful for VT and can be harmful if VT is misdiagnosed as some SVTs. Metoprolol, a beta-blocker, can worsen hypotension or heart failure in an acute VT scenario and isn’t considered first-line. Lidocaine is an alternative if amiodarone is unavailable or in certain ischemic VT cases, but amiodarone generally offers better success and safety as the initial choice. Typical dosing starts with 150 mg IV over 10 minutes, with the option to follow with a maintenance infusion if the tachycardia recurs. If the patient shows signs of instability, electrical cardioversion takes priority.