Diltiazem treats which arrhythmias?

• A. Ventricular fibrillation
• B. PVST, atrial fibrillation, atrial flutter
• C. Sinus tachycardia
• D. Bradycardia

Answer: (B)

Calcium channel blockers that act on the heart slow AV nodal conduction, giving rate control in tachyarrhythmias. Diltiazem is a non-dihydropyridine calcium channel blocker with prominent effects on the AV node. By reducing automaticity at the SA node and, more importantly, slowing conduction through the AV node and increasing AV nodal refractoriness, it decreases the ventricular rate in atrial tachyarrhythmias.

This makes it useful for conditions where the problem is rapid impulses from the atria passing through the AV node to the ventricles—paroxysmal supraventricular tachycardia, atrial fibrillation, and atrial flutter—where controlling the ventricular response improves symptoms and hemodynamics. It does not terminate ventricular fibrillation or other ventricular tachyarrhythmias, and it isn’t used to treat sinus tachycardia or bradycardia; in fact, AV nodal blockade can worsen bradycardia.