Atrial fibrillation (A-fib or AF) is an irregular or abnormal heartbeat (arrhythmia).
In A-fib, the upper chambers of the heart (the atria) beat irregularly because electrical signals that control the heart are not functioning properly. As a result, blood is not moved out of the upper heart chambers as quickly as it should be and blood clots can form. Blood clots increase the risk of stroke.
There are two types of atrial fibrillation:
- Paroxysmal (or intermittent) A-fib refers to episodes that last under 24 hours and go away on their own within seven days
- Persistent A-fib lasts more than seven days
Atrial fibrillation often begins as paroxysmal and progresses to persistent.
Atrial fibrillation isn't usually life-threatening in people who are generally healthy, but it can be serious and potentially life-threatening in people who have underlying health conditions such as diabetes, high blood pressure, or other heart diseases.
The blood clots that can result from A-fib also increase the risk of stroke, especially in those who:
- Are over the age of 65
- Had a previous stroke
- Have high blood pressure (hypertension), diabetes, or congestive heart failure
What Causes Atrial Fibrillation?
The most common causes of atrial fibrillation include heart conditions such as:
- Heart failure
- Heart disease due to chronic high blood pressure (hypertensive heart disease)
- Heart attack
- Heart valve disease, such as mitral regurgitation or mitral stenosis
- Coronary artery disease
- Congenital heart defects
- Complications from heart surgery and sometimes complications from other types of surgery
In addition to underlying heart disease, other risk factors for developing A-fib include:
- Advanced age
- Family history of A-fib
- Use of stimulants such as caffeine or nicotine
- Diabetes
- Alcohol binge drinking
- Supraventricular tachycardia (SVT)
- Obesity
- Overactive thyroid gland (hyperthyroidism)
- Sleep apnea
- Asthma
- Certain medications, including drugs that stimulate the heart such as theophylline
- Chronic lung diseases such as emphysema
- Chronic kidney disease (CKD)
- Viral infections
What Are Symptoms of Atrial Fibrillation?
Atrial fibrillation may not always cause symptoms. When symptoms occur, mild symptoms may include:
- Irregular heartbeat (arrhythmia)
- Fast heartbeat
- Heart palpitations
- Sensation of tightness, pain, or discomfort in the chest
- Mild shortness of breath
- Lightheadedness
- Weakness
- Mild fatigue, especially with exercise
Severe symptoms of atrial fibrillation may include:
- Severe fatigue
- Chest pain (angina)
- Difficulty breathing, both with and without exertion
- Fainting
What is the Treatment for Atrial Fibrillation?
Treatment for atrial fibrillation is aimed at controlling heart rhythm and rate and stopping blood clots from forming (anticoagulation) to prevent stroke.
Treatment to control heart rhythm includes:
- Electrical cardioversion
- Usually a first-line treatment in young patients who have symptoms
- Antiarrhythmics
- Ablation (catheter based, surgical, or hybrid) using heat (radiofrequency ablation) or cold (cryoablation)
- Surgical procedures, including the “maze procedure”
Treatment to control heart rate includes:
- Medications
- Amiodarone (Cordarone, Nexterone)
- Beta-blockers
- Digoxin (Lanoxin)
- Non-dihydropyridine calcium channel blockers
- Permanent pacemaker (used when other rate and rhythm control alternatives have not been successful)
Anticoagulation treatments include:
- Aspirin
- Warfarin
- Intravenous (IV) heparin or low-molecular-weight heparin (LMWH)
- Newer oral anticoagulants
- Direct thrombin inhibitor: Dabigatran (Pradaxa)
- Factor Xa inhibitors
- Apixaban (Eliquis)
- Edoxaban (Savaysa)
- Rivaroxaban (Xarelto)
From 
Image Source: iStock Images
http://emedicine.medscape.com/article/151066-overview
https://www.uptodate.com/contents/atrial-fibrillation-beyond-the-basics?search=Atrial%20Fibrillation&source=search_result&selectedTitle=6~150&usage_type=default&display_rank=6#H3
https://www.heart.org/en/health-topics/atrial-fibrillation/who-is-at-risk-for-atrial-fibrillation-af-or-afib