Diagnosis and Classification

ECG: irregularly irregular rhythm with absent distinct P waves and fibrillatory baseline. Ventricular rate typically 100–170 bpm uncontrolled. Classification by duration: Paroxysmal (terminates spontaneously within 7 days), Persistent (>7 days), Long-standing persistent (>12 months), Permanent (rhythm control abandoned). Causes: hypertension (#1), valvular disease (mitral stenosis), CAD, heart failure, thyrotoxicosis, alcohol ('holiday heart'), sleep apnea. Initial evaluation: TSH (rule out thyrotoxicosis), echo (valve disease, LV function, LAA thrombus), ECG to confirm.

Rate Control vs Rhythm Control

Rate control first-line for most patients (age ≥65, long-standing A-fib, minimal symptoms). Target HR <110 bpm at rest. Drugs: beta-blockers (metoprolol — first-line; carvedilol/bisoprolol for HFrEF), non-dihydropyridine CCBs (diltiazem, verapamil — contraindicated in HFrEF), digoxin (HFrEF adjunct; poor rate control with exertion). Rhythm control preferred for: symptomatic despite rate control, younger patients (<65), tachycardia-mediated cardiomyopathy, new-onset A-fib. 48-hour rule: if onset <48h, cardiovert with immediate anticoagulation. If onset >48h or unknown: anticoagulate ≥3 weeks OR TEE to exclude LAA thrombus before cardioversion; anticoagulate ≥4 weeks post-cardioversion. Antiarrhythmics for maintenance: flecainide/propafenone (no structural disease), amiodarone (HFrEF/CAD — most effective but most toxic), sotalol, dofetilide.

Anticoagulation: CHA2DS2-VASc Scoring

CHA2DS2-VASc: CHF(1)+HTN(1)+Age≥75(2)+DM(1)+Stroke/TIA(2)+Vascular disease(1)+Age 65–74(1)+Sex category female(1). Anticoagulate when score ≥2 in men, ≥3 in women. DOACs (apixaban, rivaroxaban, dabigatran, edoxaban) preferred over warfarin for non-valvular A-fib — no INR monitoring, lower intracranial bleeding risk, fixed dosing. Warfarin required for: mechanical heart valves (RE-ALIGN trial showed dabigatran inferior), moderate-severe rheumatic mitral stenosis. Apixaban has most favorable bleeding profile (ARISTOTLE trial). Aspirin alone is NOT adequate stroke prevention in A-fib. HAS-BLED score estimates bleeding risk but should never override anticoagulation when clearly indicated.