AF can result from a variety of conditions. Common ones include:
- High blood pressure
- Coronary artery disease
- Heart valve disease
- Chronic lung diseases
- Hyperthyroidism
- Alcohol use, particularly binge drinking
- Previous heart surgery
- Viral infections
- Certain medications or other substances
Other times, AF can occur in individuals without any known underlying condition (so-called "lone AF").

**Symptoms**: Some people with AF don't have any symptoms, but others may experience:
- Palpitations (feeling like the heart is racing, pounding, or fluttering)
- Fatigue
- Dizziness or lightheadedness
- Shortness of breath
- Chest pain or pressure
- Reduced ability to exercise
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