Atrial fibrillation occurs when the heart’s two upper chambers (the atria) beat chaotically and irregularly. This can cause blood to pool in the atria because it isn’t pumped regularly into the heart’s two lower chambers (ventricles). As a result, the upper and lower chambers don’t work in sync.
What causes atrial fibrillation?
Atrial fibrillation is an arrhythmia—a problem with the electrical signals that cause the heart to beat.
Normally, the electrical impulse that acts as the heart’s “natural pacemaker” begins in the heart’s right atrium and spreads throughout the atria. From there, the impulses travel to the left and right ventricles of the heart.
In atrial fibrillation, the signals don’t start in the right atrium like they should. Instead, they start in another part of the atria or in the pulmonary veins, which makes the signals disorganized. This can cause problems between the upper and lower chambers of the heart.
Atrial fibrillation can happen every once in a while or become a long-term heart condition that lasts many years. Possible causes of atrial fibrillation include:
- High blood pressure
- Heart attacks
- Coronary artery disease
- Abnormal heart valves
- Heart defects you are born with (congenital)
- Overactive thyroid gland or other metabolic imbalance
- Exposure to stimulants including medications, caffeine, tobacco, and alcohol
- Sick sinus syndrome
- Lung diseases
- Previous heart surgery
- Viral infections
- Stress due to pneumonia, surgery or other illnesses
- Sleep apnea
Symptoms of atrial fibrillation
The lower chambers of the heart, the ventricles, are responsible for pumping blood to the lungs and body. Atrial fibrillation can disrupt their normal rhythm and lead to the following:
- Shortness of breath
- Chest pain
- Heart palpitations
- Dizziness or fainting
- Fatigue (feeling tired)
Sometimes atrial fibrillation doesn’t cause any symptoms and is caught when your doctor does a test for another condition.
How is atrial fibrillation diagnosed?
Your doctor can diagnose atrial fibrillation using a combination of your medical history, a physical exam (pulse check and listening to heart sounds), and the results of the following tests:
- Blood tests
- Chest X-ray
- Electrocardiogram (EKG)
- Holter and event monitors
- Stress testing
- Transesophageal echocardiography (TEE)
How is atrial fibrillation treated? Generally, the treatment goals for atrial fibrillation are to:
- Reset the rhythm or control the rate
- Prevent blood clots
If atrial fibrillation isn’t caused by an underlying heart condition, it may not need any treatment and could go away on its own. However, repeat episodes can permanently damage the heart and increase your risk of a stroke, so your doctor may treat it in one of several ways:
- Blood thinners to prevent blood clots
- Medicines to control the heart rate (beta blockers, calcium channel blockers, or digitalis)
- Electrical cardioversion
- Anti-arrhythmic medications to prevent future episodes of atrial fibrillation after electrical cardioversion
- Atrioventricular (AV) node ablation
- Maze surgery