Which antiarrhythmic listed is a potassium channel blocker commonly used to treat atrial fibrillation?

Prepare for the Certification in Clinical Sleep Health exam. Use flashcards and multiple-choice questions with hints and explanations. Ace your exam!

Potassium channel blockers are class III antiarrhythmics that work by delaying repolarization, which lengthens the action potential and increases the refractory period. This helps prevent the reentry circuits that sustain atrial fibrillation. Amiodarone fits here because it is a potent potassium channel blocker with broad antiarrhythmic effects. It slows repolarization and prolongs the QT interval, aiding rhythm control in AF and often usable when other options are limited. The other drugs listed don’t primarily block potassium channels: flecainide and propafenone are sodium channel blockers (class IC) used mainly for rhythm control in suitable patients, while diltiazem is a calcium channel blocker (class IV) used mainly for rate control. Thus, amiodarone is the potassium channel blocker commonly used for atrial fibrillation.