Atrial fibrillation is an irregular heart rhythm (known as arrhythmia) that starts in the upper parts (atria) of the heart. During atrial fibrillation, a disorder of the heart’s electrical system causes the atria to quiver, or fibrillate. The quivering upsets the normal rhythm between the atria and the lower parts (ventricles) of the heart. The lower parts may beat fast and without a regular rhythm.
When the heart doesn’t beat regularly, blood can collect, or pool, in the atria. Pooled blood is more likely to form clots. If the heart pumps a clot into the bloodstream, the clot can travel to the brain and block blood flow, causing a stroke. Atrial fibrillation can also lead to heart failure.
Symptoms of Atrial Fibrillation
- Feeling dizzy or lightheaded
- Feeling out of breath
- Feeling weak and tired
- A feeling that the heart is fluttering, racing or pounding (palpitations)
- A feeling that the heart is beating unevenly
- Chest pain (angina)
Atrial fibrillation is common, especially in older adults, and may not cause obvious symptoms. Individuals experiencing any of the symptoms listed should see a doctor. Finding and treating atrial fibrillation right away can help you avoid serious problems.
Causes of Atrial Fibrillation
Additional contributing factors include:
- Other medical problems, such as lung disease, pneumonia or a high thyroid level (hyperthyroidism).
- Heart surgery
- Heavy alcohol use - Having more than 3 drinks a day over many years can cause long-lasting atrial fibrillation. Binge drinking (consuming a large amount of alcohol at one time) may also cause a spell (episode) of atrial fibrillation.
- Use of stimulants. These include caffeine, nicotine, medicines such as decongestants and illegal drugs such as cocaine.
Diagnosing Atrial Fibrillation
Atrial fibrillation is generally diagnosed with an electrocardiogram, which monitors the heart’s electrical activity, or an echocardiogram, to show how well the heart is pumping and whether the heart valves are damaged.