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.
Diagnosis & workup
Diagnostics & workup: - 12-lead ECG: irregularly irregular rhythm, absent P waves - CHA2DS2-VASc score for stroke risk - HAS-BLED score for bleeding risk - Echocardiography: LA size, LV function, valvular disease - TSH to exclude hyperthyroidism - Holter or event monitor for paroxysmal AF - BMP including K+, Mg2+
Risk factors: - Age >65 (prevalence 10% in >80y) - Hypertension (present in ~70%) - Heart failure - Valvular heart disease (especially mitral stenosis) - Obesity - Obstructive sleep apnea (2-4x increased risk) - Hyperthyroidism and alcohol (holiday heart)