Question:medium
What is the drug of choice for digitalis-induced ventricular tachycardia?
What is the drug of choice for digitalis-induced ventricular tachycardia?
Show Hint
Think of the class Ib antiarrhythmic used to suppress ventricular ectopy in glycoside toxicity.
Updated On: Jun 23, 2026
- Lidocaine
- Reducing dosage of digoxin itself reverses the condition
- Verapamil
- Beta blockers
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: In a poisoned heart from cardiac glycosides, the dominant emergency is the rhythm disturbance. When that rhythm is of ventricular origin (VT or frequent ventricular ectopy), the clinician needs an agent that quiets the ventricle quickly.
Step 2: Lidocaine, a class Ib antiarrhythmic, fits this need. It shortens the action potential, raises the fibrillation threshold, and dampens the abnormal ventricular automaticity seen in glycoside excess, all while leaving sinoatrial and AV nodal conduction relatively untouched. That is exactly why it is preferred when digitalis triggers ventricular arrhythmias.
Step 3: Compare the alternatives. Verapamil slows AV conduction and can elevate serum digoxin, a double hazard. Beta blockers may deepen any existing block and are more appropriate for supraventricular acceleration. Simply trimming the digoxin dose is too slow to terminate an active VT.
Step 4: Adjuncts include potassium correction, atropine for bradyarrhythmias, and digoxin-specific Fab fragments for life-threatening cases, but the targeted antiarrhythmic for the ventricular event is lidocaine.
\[\boxed{\text{Lidocaine}}\]
Step 2: Lidocaine, a class Ib antiarrhythmic, fits this need. It shortens the action potential, raises the fibrillation threshold, and dampens the abnormal ventricular automaticity seen in glycoside excess, all while leaving sinoatrial and AV nodal conduction relatively untouched. That is exactly why it is preferred when digitalis triggers ventricular arrhythmias.
Step 3: Compare the alternatives. Verapamil slows AV conduction and can elevate serum digoxin, a double hazard. Beta blockers may deepen any existing block and are more appropriate for supraventricular acceleration. Simply trimming the digoxin dose is too slow to terminate an active VT.
Step 4: Adjuncts include potassium correction, atropine for bradyarrhythmias, and digoxin-specific Fab fragments for life-threatening cases, but the targeted antiarrhythmic for the ventricular event is lidocaine.
\[\boxed{\text{Lidocaine}}\]
Was this answer helpful?
0
