Pathophysiology
Clinical meaning
Atrial Fibrillation involves disorganized electrical activity from multiple re-entrant wavelets and ectopic foci from pulmonary vein ostia. Atrial myocytes undergo electrical remodeling with shortened action potential duration. Structural remodeling includes atrial fibrosis creating substrate for re-entry. Loss of atrial kick reduces cardiac output by 15-25% and causes left atrial appendage stasis increasing thromboembolic risk. CHA2DS2-VASc score guides anticoagulation.