Patients with chronic atrial fibrillation may need to take certain antiarrhythmic medication long-term daily to stop episodes before they can occur. This type of medication is typically only prescribed when the patient's heart rhythm has already been corrected with the use of electrical cardioversion. The most common antiarrhythmic medications used include flecainide, amiodarone, dofetilide, propafenone, and sotalol. Different antiarrhythmic drugs utilize different mechanisms to restore and maintain a patient's healthy heart rhythm and function. Some of these drugs work by increasing or decreasing the velocity of electrical conduction in the tissues. Others work by changing the excitability of the cells that make up the heart through the alteration of the effective refractory period duration. Another mechanism antiarrhythmic medications use to help maintain a patient's heart rhythm is by inhibiting the abnormal automaticity that occurs in the tissues and is known to trigger atrial fibrillation.