NAPLEX (North American Pharmacist Licensure Examination) Practice Exam 2026 - Free NAPLEX Practice Questions and Study Guide

Antiarrhythmic drugs are categorized into four main classes Class 1, 2, 3, and 4. While all classes have applications in treating different cardiac arrhythmias, Class 2 antiarrhythmics primarily work to control heart rate in atrial fibrillation (A-Fib). Class 1 antiarrhythmics mainly target the sodium channels in the heart, making them more suitable for treating ventricular arrhythmias. Class 3 antiarrhythmics have a broader range of effects on potassium channels and are used for both rate control and rhythm control in A-Fib. Class 4 antiarrhythmics primarily block calcium channels and are often used for treating supraventricular tachycardias (SVTs) such as atrial flutter. Overall, Class 2 antiarrhythmics, such as beta blockers or calcium channel blockers, are the preferred choice for rate control in A-Fib due to their specific mechanism of action.