Definition #
Atrial fibrillation is a supraventricular arrhythmia characterized by disorganized atrial electrical activity leading to ineffective atrial contraction.
Mechanism #
The arrhythmia is caused by multiple re-entry circuits within the atria, resulting in irregular atrial depolarization and an irregular ventricular response.
Key features #
- Absence of P waves
- Irregularly irregular RR intervals
- Variable ventricular rate
Clinical significance #
Atrial fibrillation significantly increases the risk of thromboembolism, particularly ischemic stroke.
Diagnosis #
- Electrocardiogram (ECG)
- Irregular RR intervals
- No distinct P waves
Management principles #
- Rate control
- Rhythm control
- Anticoagulation based on stroke risk
Exam pearls #
- AF = increased stroke risk
- Irregularly irregular rhythm
- Anticoagulation decisions depend on risk stratification
