Atrial fibrillation (AF) affects over 6 million Americans and is the most common cardiac arrhythmia requiring medical management. It is caused by chaotic electrical activity in the atria, leading to an irregular — and often rapid — ventricular rate. AF carries a 5-fold increased risk of stroke because blood stagnates in the non-contracting atria, particularly the left atrial appendage, forming clots that can embolise to the brain. Management has three pillars: stroke prevention with anticoagulation, rate control, and rhythm control. Direct oral anticoagulants (apixaban, rivaroxaban) have largely replaced warfarin for stroke prevention in non-valvular AF, offering equivalent or superior efficacy with simpler dosing and reduced intracranial haemorrhage risk. Catheter ablation is increasingly used to maintain sinus rhythm in symptomatic patients.
