In atrial fibrillation the upper chambers of the heart quiver in a chaotic way instead of beating in rhythm, so the pulse becomes irregular and often fast. Blood can pool in the atria and form clots, which makes stroke the main danger.
Key symptoms
- Palpitations or a fluttering, racing heartbeat
- Shortness of breath and less exercise tolerance
- Fatigue, lightheadedness or near fainting
- Chest discomfort, mostly when the rate is fast
- Sometimes no symptoms; found on a routine check
What you find on exam
- Irregularly irregular pulse
- Rate at the wrist lower than at the apex (pulse deficit)
- Blood pressure; look for low pressure or signs of shock
- Signs of heart failure: crackles, raised jugular venous pressure, leg edema
- Clues to a cause: enlarged thyroid, murmurs, fever
Tests
- 12-lead ECG: no P waves and irregular QRS complexes
- Thyroid tests, electrolytes, kidney function, blood count
- Echocardiogram: chamber size, valves and pump function
- Stroke risk score (CHA2DS2-VASc) and bleeding risk; troponin if chest pain
Treatment basics
- Unstable patient: synchronized cardioversion right away
- Rate control with a beta blocker such as metoprolol, or with diltiazem
- Anticoagulation based on stroke risk, usually a direct oral anticoagulant such as apixaban
- Rhythm control in selected patients: cardioversion, antiarrhythmics or catheter ablation
- Treat triggers: thyroid disease, alcohol, sleep apnea, infection
Red flags
- Low blood pressure, chest pain or confusion with a fast rate
- Sudden weakness, facial droop or trouble speaking
- Very fast rate with breathlessness at rest or acute heart failure
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.