Atrial fibrillation (AF or AFib) is an abnormal heart rhythm in which electrical activity in the atria, the heart’s two upper chambers, becomes rapid and disorganized. The atria no longer contract in a coordinated pattern, and electrical impulses reach the ventricles irregularly.

AF may occur in brief episodes, persist for days or longer, or become continuous. It is clinically important because it can reduce cardiac efficiency, worsen heart failure, and allow blood to stagnate in the left atrium, where clots may form and later cause ischemic stroke. The basic electrical and circulatory changes are described in the CDC atrial fibrillation overview.

AF is not a single problem with one treatment. Management depends on symptoms, episode duration, age, structural heart disease, kidney and liver function, stroke risk, bleeding risk, and whether another condition is driving the arrhythmia.

Care generally addresses three major issues:

• preventing stroke and systemic embolism;
• controlling an excessively fast ventricular rate;
• restoring or maintaining sinus rhythm when rhythm control is appropriate.

Treatment of hypertension, obesity, sleep apnea, heart failure, and excessive alcohol use is also important because these conditions can promote recurrent AF.

What Does Atrial Fibrillation Feel Like?

Symptoms vary considerably. Some patients notice every episode, while others have persistent AF without obvious symptoms and are diagnosed during an examination or rhythm recording. Palpitations may feel like fluttering, pounding, skipped beats, or an irregular pulse. Fatigue and reduced exercise tolerance are common because the ventricles may fill less efficiently and the heart rate may rise excessively with activity. Recognized presentations are summarized in current AF symptom guidance from the National Heart, Lung, and Blood Institute.

Common symptoms include:

• irregular, fluttering, or pounding heartbeat;
• unusual fatigue or weakness;
• shortness of breath, especially with exertion;
• dizziness or lightheadedness;
• reduced exercise tolerance;
• chest discomfort;
• fainting in more severe cases.

Symptom severity does not reliably indicate stroke risk. A person with mild or no palpitations may still need anticoagulation if clinical risk factors make clot formation sufficiently likely.

Why Does AF Develop?

AF often develops when aging, disease, inflammation, pressure overload, or repeated electrical stress changes atrial tissue. Hypertension is a major contributor because long-standing elevated pressure can enlarge and remodel the left atrium. Coronary artery disease, previous myocardial infarction, heart failure, cardiomyopathy, congenital heart disease, and mitral valve disease can also create the structural and electrical environment in which AF develops.

Other recognized contributors and risk factors include:

Factor	How It May Contribute
Older age	Atrial tissue becomes more vulnerable to structural and electrical remodeling
Hypertension	Raises atrial pressure and promotes enlargement
Heart failure	Changes atrial pressure, volume, and conduction
Obstructive sleep apnea	Repeated oxygen changes and pressure shifts can promote arrhythmia
Obesity	Associated with atrial enlargement, inflammation, and sleep apnea
Hyperthyroidism	Can increase heart rate and electrical excitability
Diabetes and kidney disease	Increase cardiovascular and thromboembolic risk
Alcohol exposure	Heavy or episodic intake may trigger AF
Family history	Some patients have inherited susceptibility

Acute infection, major surgery, electrolyte abnormalities, stimulants, and some illicit drugs can also trigger episodes. In other patients no single cause can be identified, although investigation may uncover treatable contributors such as sleep apnea or previously unrecognized hypertension.

How Is Atrial Fibrillation Diagnosed?

Diagnosis requires documentation of the abnormal rhythm, usually with an electrocardiogram, or ECG. AF typically produces an irregularly irregular ventricular rhythm without consistent P waves. If episodes are intermittent, an office ECG may be normal between events, so longer monitoring may be necessary. MedlinePlus provides additional diagnostic testing guidance on AF evaluation and the tests that may be used to confirm the condition.

Evaluation may involve:

• 12-lead ECG: records cardiac electrical activity at one point in time.
• Holter monitor: continuously records rhythm, commonly for 24 hours or longer.
• Adhesive ECG patch: can monitor rhythm over several days or weeks.
• Event recorder: captures intermittent episodes over a longer period.
• Implanted loop recorder: may be used when episodes are uncommon but clinically important.
• Wearable rhythm devices: selected validated devices can provide useful rhythm recordings.

Blood tests commonly evaluate electrolytes, thyroid function, and kidney function. Transthoracic echocardiography assesses atrial and ventricular size, valve disease, pumping function, and other structural abnormalities. Transesophageal echocardiography may be used when clinicians need a closer view of the left atrium and left atrial appendage, particularly before certain cardioversion strategies. Sleep studies, exercise testing, or evaluation for coronary ischemia may be added when the history suggests a specific contributor.

Treatment Is Organized Around Stroke, Rate, and Rhythm

Treatment is individualized, but the major decisions are systematic. Clinicians first assess thromboembolic risk and determine whether anticoagulation is warranted. They then consider whether the ventricular rate requires treatment and whether restoring sinus rhythm is likely to improve symptoms, exercise capacity, heart failure, or other clinically meaningful outcomes.

The current U.S. AF management guideline from the American College of Cardiology and European AF treatment guidance from the European Society of Cardiology support this integrated approach.

Treatment Objective	Typical Approaches
Reduce stroke risk	Oral anticoagulants when indicated
Slow ventricular rate	Beta blockers, diltiazem, verapamil, or selected use of digoxin
Restore sinus rhythm	Cardioversion, antiarrhythmic drugs, or catheter ablation
Reduce recurrence drivers	Blood-pressure control, sleep apnea treatment, weight management, alcohol reduction

Electrical cardioversion, antiarrhythmic medication, and catheter ablation are all rhythm-control strategies, but they are not interchangeable for every patient. Stroke prevention remains a separate decision, which is why successful rhythm control does not automatically remove the need for an anticoagulant.

Medication-Based Treatment

Rate-Control Medicines

Beta blockers such as metoprolol, atenolol, bisoprolol, and carvedilol reduce sympathetic stimulation of the heart and slow conduction through the atrioventricular node. They are widely used as first-line rate-control drugs when the clinical setting permits. Metoprolol is available as immediate-release and extended-release tablets and as an intravenous preparation. Intravenous beta blockade can begin reducing ventricular rate within minutes, while oral preparations generally start having clinically relevant effects within hours.

Common adverse effects include fatigue, dizziness, bradycardia, and low blood pressure. Beta blockers may worsen bronchospasm in susceptible patients and require caution when significant conduction disease or an already slow resting heart rate is present.

Diltiazem and verapamil are nondihydropyridine calcium channel blockers that also slow conduction through the AV node. Intravenous diltiazem can provide relatively rapid rate control in a monitored acute-care setting, while oral formulations are used for longer-term management. Possible adverse effects include hypotension, bradycardia, constipation, and peripheral edema. Because these drugs can reduce myocardial contractility, they are generally avoided when left ventricular systolic function is significantly reduced.

Digoxin slows AV-node conduction mainly through increased vagal activity. It may be considered when beta blockers or calcium channel blockers are inadequate or poorly tolerated, particularly in selected patients with heart failure. It usually acts more slowly and may control the ventricular rate less effectively during exercise. Toxicity can produce nausea, confusion, visual disturbances, severe bradycardia, or ventricular arrhythmias. Kidney function and interacting medications therefore require attention. Broader descriptions of these drug classes appear in the American Heart Association’s AF medication guidance.

Anticoagulants for Stroke Prevention

Anticoagulation does not make AF disappear and usually does not improve palpitations. Its purpose is to reduce thrombus formation and prevent ischemic stroke or systemic embolism.

For many patients who require anticoagulation and do not have a mechanical heart valve or moderate-to-severe rheumatic mitral stenosis, direct oral anticoagulants are commonly preferred over warfarin.

Active Ingredient	Drug Type	Main Purpose in AF
Apixaban	Factor Xa inhibitor	Stroke and systemic embolism prevention
Rivaroxaban	Factor Xa inhibitor	Stroke and systemic embolism prevention
Edoxaban	Factor Xa inhibitor	Stroke and systemic embolism prevention
Dabigatran	Direct thrombin inhibitor	Stroke and systemic embolism prevention
Warfarin	Vitamin K antagonist	Anticoagulation in selected patients, including certain valvular conditions

These direct oral anticoagulants begin producing anticoagulant activity within hours. Apixaban, for example, is available as 2.5 mg and 5 mg tablets for adults in the United States, although the clinically appropriate dose depends on indication and patient-specific factors. FDA Apixaban prescribing information details its indications, strengths, contraindications, and important interactions.

Bleeding is the principal adverse effect of all anticoagulants. Kidney function, age, body weight, liver disease, prior bleeding, and interacting drugs can influence drug selection or dosing. Strong P-glycoprotein or CYP3A4 inhibitors and inducers are important with some agents, and concurrent antiplatelet medicines or nonsteroidal anti-inflammatory drugs can further increase bleeding risk.

Warfarin reduces production of vitamin K-dependent clotting factors. Its anticoagulant effect develops over several days, and treatment requires INR testing because diet, illness, antibiotics, antiarrhythmics, and numerous other medicines can change its effect. Warfarin remains important for patients with mechanical heart valves and for many patients with moderate-to-severe rheumatic mitral stenosis.

An active ingredient, generic equivalent, and brand-name product are distinct concepts. Apixaban is the active ingredient, Eliquis is a brand-name product, while approved generic versions contain the same active ingredient and must meet applicable regulatory standards for quality and performance. For patients who obtain prescribed medicines through Global Canadian pharmacy, this international service is one example of a regulated source where medications are dispensed in accordance with applicable provincial pharmacy requirements and reviewed by a pharmacist before being provided to the patient. Health Canada’s searchable drug product database can also be used to confirm whether a specific medicine is authorized for sale in Canada and to identify its active ingredient, manufacturer, and marketed forms. These safeguards do not replace medical assessment, and prescription medicines used for atrial fibrillation still require an appropriate prescription and review of contraindications before dispensing.

Rhythm-Control Medicines

Antiarrhythmic drugs are used when restoring or maintaining sinus rhythm is clinically appropriate.

Flecainide and propafenone are class IC agents that block cardiac sodium channels. In carefully selected patients without previous myocardial infarction or significant structural heart disease, they may be used for long-term rhythm control and sometimes for clinician-directed “pill-in-the-pocket” cardioversion after safety has been established. Conversion may occur within hours, but these drugs can also provoke serious arrhythmias in unsuitable patients.

Dofetilide and sotalol prolong cardiac repolarization. Both can prolong the QT interval and cause torsades de pointes, so kidney function, potassium, magnesium, baseline ECG findings, and other QT-prolonging medications must be considered. In the United States, dofetilide initiation or re-initiation requires a facility capable of continuous ECG monitoring and renal-based dose selection.

Dronedarone may be appropriate for some patients with paroxysmal or persistent AF who are in sinus rhythm. It is contraindicated in permanent AF and in certain patients with symptomatic or recently decompensated heart failure.

Amiodarone can maintain sinus rhythm even in some patients with structural heart disease, but its long-term safety profile limits routine first-line use. Potential adverse effects involve the thyroid, lungs, liver, eyes, nervous system, and skin. It can also increase the effects of warfarin and raise digoxin concentrations. Clinicians therefore commonly reserve amiodarone for situations in which safer rhythm-control strategies are unsuitable or ineffective.

Important Medication Interactions and Contraindications

AF treatment frequently involves drugs that affect the same cardiovascular pathways. Several combinations require additional monitoring or may be unsuitable in particular patients:

• Beta blockers, diltiazem, verapamil, digoxin, and some antiarrhythmics can cause excessive bradycardia when combined.
• Anticoagulants taken with antiplatelet drugs or NSAIDs can increase bleeding risk.
• Flecainide and propafenone are generally avoided after myocardial infarction or in substantial structural heart disease.
• Sotalol and dofetilide require careful assessment of renal function and QT prolongation.
• Amiodarone interacts with several cardiovascular medicines, including warfarin and digoxin.

Advanced kidney or liver disease, electrolyte abnormalities, pregnancy, conduction disorders, and implanted cardiac devices can also change which treatments are appropriate. Prescription selection therefore requires more than matching a drug name to an AF diagnosis.

When Is Catheter Ablation Considered?

Catheter ablation is a rhythm-control procedure that targets electrical triggers responsible for AF. Most procedures focus on pulmonary vein isolation because many AF episodes originate from tissue near the pulmonary veins. Thin catheters are advanced through blood vessels into the heart, where energy is used to electrically isolate these areas. Radiofrequency ablation and cryoablation are established thermal techniques, while pulsed-field ablation uses nonthermal electrical energy. A clinical description of the procedure is available in the Mayo Clinic overview of atrial fibrillation ablation.

Ablation may be considered when:

• symptomatic AF continues despite antiarrhythmic medication;
• medication causes unacceptable adverse effects;
• an electrophysiologist and patient select ablation as an initial rhythm-control strategy;
• AF occurs together with selected forms of heart failure and reduced ejection fraction.

Current guidelines also support first-line catheter ablation in selected patients with symptomatic paroxysmal AF.

Ablation can reduce AF burden and improve quality of life, but recurrence remains possible and some patients require another procedure. Potential complications include bleeding at vascular access sites, pericardial effusion or tamponade, stroke or transient ischemic attack, pulmonary vein stenosis, phrenic nerve injury, and rare esophageal injury.

Anticoagulation is managed carefully before, during, and after ablation. Successful restoration of sinus rhythm does not by itself prove that stroke risk has disappeared. Decisions about longer-term anticoagulation remain based on the patient’s thromboembolic risk profile.

Other Established Non-Drug Treatment

Electrical cardioversion delivers a synchronized electrical shock under sedation to restore sinus rhythm. It is used urgently when AF causes hemodynamic instability and electively in selected stable patients. When AF has been present long enough for atrial thrombus to be a concern, anticoagulation or transesophageal echocardiography is incorporated into the cardioversion strategy to reduce embolic risk.

Management of contributing conditions is also part of treatment. Depending on the patient, this can include:

• treatment of obstructive sleep apnea;
• blood-pressure control;
• medically appropriate weight reduction;
• regular physical activity;
• smoking cessation;
• limiting excessive alcohol exposure;
• treatment of hyperthyroidism;
• correction of significant electrolyte abnormalities;
• appropriate management of heart failure.

These measures address factors that can promote AF recurrence and cannot be replaced by rate-control medication or ablation alone.

When Does AF Require Emergency Care?

Emergency medical assessment is appropriate when a rapid or irregular heartbeat occurs with any of the following:

• chest pain or pressure;
• severe shortness of breath;
• fainting or near-fainting;
• marked weakness or confusion;
• signs of circulatory collapse;
• facial drooping or arm weakness;
• difficulty speaking;
• sudden loss of vision;
• severe new loss of balance or coordination.

These findings may indicate myocardial ischemia, hemodynamic instability, acute heart failure, or stroke.

A newly persistent irregular pulse or recurrent palpitations without severe symptoms still warrants medical evaluation, particularly when accompanied by dizziness, reduced exercise tolerance, or known cardiovascular disease. Because AF can be intermittent or completely asymptomatic, the intensity of palpitations alone cannot determine whether diagnostic testing or stroke-risk assessment is necessary.

Medical disclaimer

This article provides general medical information and does not replace diagnosis, prescribing, medication review, or treatment by a qualified healthcare professional.

Sources

1. Atrial Fibrillation Diagnosis and Management – https://www.nice.org.uk/guidance/ng196
2. 2024 Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation – https://www.hrsonline.org/resource/2024-ehra-hrs-aphrs-lahrs-expert-consensus-statement-on-catheter-and-surgical-ablation-of-atrial-fibrillation/
3. Atrial Fibrillation – https://www.nhs.uk/conditions/atrial-fibrillation/
4. Atrial Fibrillation Symptoms and Treatment – https://my.clevelandclinic.org/health/diseases/16765-atrial-fibrillation-afib
5. What Is Afib? – https://www.hopkinsmedicine.org/health/conditions-and-diseases/atrial-fibrillation
6. Atrial Fibrillation – https://www.merckmanuals.com/professional/cardiovascular-disorders/specific-cardiac-arrhythmias/atrial-fibrillation
7. Atrial Fibrillation – https://www.ucsfhealth.org/care/conditions/atrial-fibrillation