What are the symptoms of atrial fibrillation (afib)?

Symptoms of Atrial Fibrillation

Atrial fibrillation presents with a broad spectrum of symptoms ranging from none at all to severely disabling, with palpitations, fatigue, dyspnea, chest pain, and lightheadedness being the most common complaints, though 10-40% of patients remain completely asymptomatic. 1, 2

Common Cardiac-Specific Symptoms

• Palpitations are the most characteristic cardiac symptom, though they are actually less common than non-specific symptoms 1, 3
• Chest pain occurs frequently and may mimic angina 1, 3
• Irregular heartbeat sensation is particularly prominent in vagally-mediated AF where heart rate is relatively slow 1

Non-Specific Symptoms (More Common Than Cardiac Symptoms)

• Fatigue is one of the most prevalent symptoms and significantly impairs quality of life 1, 3, 2
• Dyspnea (shortness of breath) occurs both at rest and with exertion 1, 3
• Exertional intolerance limits physical activity 2
• Lightheadedness or presyncope can occur, particularly with rapid ventricular rates 1, 2

Serious Symptoms Requiring Urgent Evaluation

• Syncope is uncommon but serious, usually associated with sinus node dysfunction, hemodynamic obstruction (aortic stenosis, hypertrophic cardiomyopathy), or accessory pathways 1
• Symptoms of heart failure including peripheral edema, pulmonary congestion, and decompensation 1, 4
• Polyuria may occur due to release of atrial natriuretic peptide, particularly at onset or termination of AF episodes 1

Asymptomatic Presentation (Critical Pitfall)

• 10-40% of patients with AF are completely asymptomatic, and even symptomatic patients may have asymptomatic episodes 1, 2, 5
• Asymptomatic AF carries the same stroke risk as symptomatic AF—absence of symptoms does not reduce thromboembolic risk 1
• First presentation may be a devastating stroke or heart failure without any prior warning symptoms 1, 5
• Tachycardia-mediated cardiomyopathy can develop silently in patients unaware of their arrhythmia 1

Symptom Patterns Based on AF Type

Vagally-Mediated AF

• Occurs predominantly at night, during rest, after eating, or after alcohol ingestion 1
• Preceded by progressive bradycardia 1
• Patients complain more of irregularity than dyspnea or lightheadedness due to relatively slow heart rate 1
• More common in men (4:1 ratio), typically onset age 40-50 years 1

Adrenergically-Mediated AF

• Occurs during daytime, provoked by exercise or emotional stress 1
• Onset typically associated with a specific sinus rate threshold for each patient 1
• Polyuria is a common correlate 1
• No gender differences 1

Symptom Severity Classification (Modified EHRA Scale)

The European Society of Cardiology uses this standardized scale: 1

• Score 1 (None): AF does not cause any symptoms
• Score 2a (Mild): Normal daily activity not affected by symptoms
• Score 2b (Moderate): Normal daily activity not affected but patient troubled by symptoms
• Score 3 (Severe): Normal daily activity affected by symptoms
• Score 4 (Disabling): Normal daily activity discontinued

Important Clinical Considerations

• Symptoms vary with ventricular rate, underlying cardiac function, duration of AF, and individual patient perception 1
• Women tend to be more symptomatic than men and report poorer quality of life 1
• Anxiety and depression are more prevalent in AF patients compared to the general population, with higher rates in women 1
• Symptoms may decrease over time as AF becomes permanent, particularly in elderly patients who may become asymptomatic 1
• 90% of patients describe symptoms at some point, though severity is highly variable 1

When to Suspect AF Despite Absence of Classic Symptoms

• Unexplained fatigue or exercise intolerance in at-risk patients 1, 2
• New-onset heart failure without clear precipitant 1
• Cryptogenic stroke, particularly in patients over 50 years 6
• Irregular pulse detected on routine examination 4, 3