Atrial fibrillation
Atrial fibrillation is a supraventricular tachyarrhythmia with disorganized atrial activation and an irregularly irregular ventricular response, the most common sustained arrhythmia and a major cause of stroke. Diagnosis is by ECG showing no discrete P waves with irregular RR intervals, and management addresses rate or rhythm control, stroke prevention by CHA2DS2-VASc-guided anticoagulation, and the underlying cause.
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What this article covers
- Overview
Definition: atrial fibrillation is a supraventricular tachyarrhythmia with chaotic, disorganized atrial electrical activity and loss of effective atrial contraction, producing an irregularly irregular ventricular response.
- Epidemiology
The most common sustained arrhythmia, with prevalence rising steeply with age.
- Risk factors
Age and hypertension: the dominant risk factors.
- Pathophysiology
Triggers and substrate: ectopic firing, often from the pulmonary veins, initiates and an abnormal atrial substrate sustains disorganized reentry.
- Clinical features
Palpitations and irregular pulse: an irregularly irregular rhythm.
- Differential diagnosis
Atrial flutter: organized atrial activity with sawtooth flutter waves, often regular (atrial flutter).
- Diagnosis
Establish with an ECG showing irregularly irregular rhythm without discrete P waves: the diagnostic basis is a 12-lead ECG (or rhythm strip) demonstrating absence of consistent P waves with…
- Management
First, address instability: immediate synchronized cardioversion for hemodynamic instability (hypotension, ischemia, or pulmonary edema).
- Complications
Cardioembolic stroke and systemic embolism: the principal hazard.
- Prognosis
Good with stroke prevention and rate/rhythm control, though it is often progressive.
- Prevention
Anticoagulate per CHA2DS2-VASc to prevent stroke, the key preventive measure.
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