Atrial Fibrillation: Causes, Symptoms & Treatment

Atrial fibrillation (AFib or AF) is the most common type of sustained cardiac arrhythmia (irregular heartbeat). In AFib, the upper chambers of the heart (atria) beat chaotically and irregularly, out of coordination with the lower chambers (ventricles). This results in an irregular and often rapid heartbeat that can lead to blood clots, stroke, heart failure, and other heart-related complications.

AFib affects an estimated 6 million people in the United States and 33 million worldwide. The prevalence increases with age, affecting roughly 9% of people over 65.

• Paroxysmal AFib: Episodes come and go, typically lasting less than 7 days and often resolving on their own
• Persistent AFib: Lasts more than 7 days and requires treatment (medication or cardioversion) to restore normal rhythm
• Long-standing persistent AFib: Continuous AFib lasting more than 12 months
• Permanent AFib: AFib that is accepted as the patient's baseline rhythm; efforts to restore normal rhythm have been abandoned

Common causes and risk factors include:

• High blood pressure (most common modifiable risk factor)
• Age over 60
• Heart valve disease
• Heart failure or cardiomyopathy
• Coronary artery disease
• Thyroid disorders (especially hyperthyroidism)
• Obstructive sleep apnea
• Obesity
• Excessive alcohol consumption ("holiday heart syndrome")
• Family history of AFib
• Lung diseases (COPD, pneumonia, pulmonary embolism)

Some people with AFib have no symptoms at all and discover it during a routine examination. When symptoms occur, they may include:

• Irregular, rapid, or fluttering heartbeat (palpitations)
• Fatigue and weakness
• Shortness of breath, especially during activity
• Dizziness or lightheadedness
• Chest discomfort or pressure
• Reduced exercise tolerance
• Fainting (syncope) in severe cases

• Electrocardiogram (ECG): The primary test -- shows the characteristic irregularly irregular rhythm with absence of organized P waves
• Holter monitor: Portable ECG worn for 24-48 hours to catch intermittent episodes
• Event monitor or patch monitor: Worn for days to weeks to detect infrequent episodes
• Echocardiogram: Ultrasound to assess heart structure, valve function, and atrial size
• Blood tests: Thyroid function, complete blood count, metabolic panel
• Sleep study: If sleep apnea is suspected

Stroke prevention (highest priority):

• Anticoagulant medications: Direct oral anticoagulants (DOACs) such as apixaban, rivaroxaban, dabigatran, or edoxaban are preferred over warfarin for most patients
• Left atrial appendage closure (Watchman device) for patients who cannot take anticoagulants

Rate control (controlling heart rate):

• Beta-blockers (metoprolol, atenolol)
• Calcium channel blockers (diltiazem, verapamil)
• Digoxin (usually as add-on therapy)
• Target resting heart rate below 110 bpm

Rhythm control (restoring and maintaining normal rhythm):

• Antiarrhythmic drugs (flecainide, propafenone, amiodarone, sotalol, dofetilide)
• Electrical cardioversion (synchronized shock to reset heart rhythm)
• Catheter ablation (pulmonary vein isolation) -- increasingly used as first-line rhythm control

Lifestyle modifications:

• Treat underlying conditions (hypertension, sleep apnea, thyroid disease)
• Weight loss if overweight or obese
• Limit or avoid alcohol
• Regular moderate exercise
• Manage stress

See a doctor if you notice a persistently irregular or rapid heartbeat, unexplained fatigue, or reduced exercise tolerance. Seek emergency care if you experience signs of stroke, severe chest pain, or fainting.