Atrial fibrillation overview

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Atrial fibrillation

Atrial Fibrillation Microchapters
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Joseph Nasr, M.D.[2]; Cafer Zorkun, M.D., Ph.D. [3] Anahita Deylamsalehi, M.D.[4]

Atrial fibrillation (AF or AFib) is the most common sustained cardiac arrhythmia, characterized by rapid and disorganized atrial electrical activity with consequent deterioration of atrial mechanical function. On the electrocardiogram (ECG), AF is identified by the replacement of consistent P waves with rapid oscillations or fibrillatory waves that vary in amplitude, shape, and timing, associated with an irregularly irregular ventricular response when atrioventricular conduction is intact.Joglar JA, Chung MK, Armbruster AL, Benjamin EJ, Chyou JY, Cronin EM, Deswal A, Eckhardt LL, Goldberger ZD, Gopinathannair R, Gorenek B, Hess PL, Hlatky M, Hogan G, Ibeh C, Indik JH, Kido K, Kusumoto F, Link MS, Linta KT, Marcus GM, McCarthy PM, Patel N, Patton KK, Perez MV, Piccini JP, Russo AM, Sanders P, Streur MM, Thomas V, Turakhia MP, Varosy PD, Mauri L (2024). "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation". J Am Coll Cardiol. 83 (1): 109–279. doi:10.1016/j.jacc.2023.08.017. PMID 39653651 . AF affects an estimated 59 million individuals worldwide and approximately 10.55 million adults in the United States.Ko D, Chung MK, Evans PT, Benjamin EJ, Helm RH (2025). "Atrial Fibrillation: A Review". JAMA. 333 (4): 329–342. doi:10.1001/jama.2024.22451. PMID 39847373 .

Overview

Atrial fibrillation is a supraventricular tachycardia characterized by uncoordinated atrial activation and, consequently, ineffective atrial contraction. The ECG hallmarks include: (1) irregular atrial activity, (2) absence of distinct P waves, and (3) irregular R-R intervals when atrioventricular conduction is present. The 2023 ACC/AHA/ACCP/HRS Guideline proposed a staging classification for AF evolution:

• Stage 1 (At Risk): Patients with modifiable risk factors for AF (e.g., obesity, hypertension, diabetes mellitus, obstructive sleep apnea)*
• Stage 2 (Pre-AF): Evidence of structural or electrical atrial pathology on ECG or imaging without documented AF*
• Stage 3 (AF): Documented AF, subdivided into paroxysmal (episodes lasting ≤7 days), persistent (continuous AF lasting >7 days and/or requiring cardioversion), and long-standing persistent (continuous AF >12 months)*
• Stage 4 (Permanent AF): AF accepted by the patient and clinician, with no further attempts at rhythm control*

Epidemiology and Demographics

The incidence, prevalence, and lifetime risk of AF are increasing globally, driven by population aging, rising rates of obesity, increased detection, and improved survival with AF and other cardiovascular diseases.

• The Global Burden of Disease project estimated that in 2021, approximately 52.55 million individuals (95% CI, 43.49–63.74 million) worldwide had AF or atrial flutter, with the highest prevalence in high-income countries in North America, Australasia, and Western Europe.*
• In 2023, there were an estimated 59.0 million (95% UI: 46.5 to 72.8 million) prevalent cases globally, with 378,000 (95% UI: 319,000 to 424,000) deaths attributed to AF and atrial flutter.Global Burden of Cardiovascular Diseases and Risks 2023 Collaborators (2025). "Global, Regional, and National Burden of Cardiovascular Diseases and Risk Factors in 204 Countries and Territories, 1990-2023". J Am Coll Cardiol. 86 (22): 2167–2243. doi:10.1016/j.jacc.2025.08.015. PMID 40990886 . *
• In the United States, AF prevalence was estimated at 5.2 million in 2010, with projections to rise to 12.1 million by 2030.*
• The global prevalence is higher in men (~28 million) than women (~25 million).*
• Older age is strongly associated with higher incidence (HR per 5-year increase in age, 1.66 [95% CI, 1.59–1.74]).*
• Overall lifetime risk is approximately 30% to 40% in White individuals, approximately 20% in African American individuals, and approximately 15% in Chinese individuals.*

Risk Factors

Risk factors for AF include both modifiable and nonmodifiable conditions:Chung MK, Refaat M, Shen WK, Kuber S, Estes N, Kusumoto FM, Patel N, Deshmukh AJ, Joglar JA, Abraham TP, Abuissa H, Deswal A, Diaz JC, Drazner MH, Dunbar SB, Duval S, Enriquez A, Fang JC, Fatkin D, Fuster V, Goldberger ZD, Hlatky MA, Joglar JA, Kay GN, Leclercq C, Masoudi FA, Mukherjee D, Murai R, Noseworthy PA, Packer DL, Piccini JP, Poole JE, Reddy VY, Reynolds MR, Rienstra M, Sanders P, Spertus JA, Stecker EC, Turakhia MP (2020). "Atrial Fibrillation: JACC Council Perspectives". J Am Coll Cardiol. 75 (14): 1689–1713. doi:10.1016/j.jacc.2020.02.025. PMID 32273035 .

Modifiable risk factors:

• Hypertension*
• Obesity*
• Diabetes mellitus*
• Obstructive sleep apnea*
• Coronary artery disease*
• Valvular heart disease (especially mitral stenosis and mitral regurgitation)*
• Heart failure and cardiomyopathy*
• Hyperthyroidism*
• Excessive alcohol consumption (>1 standard drink per day or binge drinking)*
• Smoking*
• Sedentary lifestyle*

Nonmodifiable risk factors:

• Older age*
• Male sex*
• European ancestry*
• Family history of AF / genetic predisposition*
• Taller height*

Acute precipitants:

• Cardiac surgery (most common postoperative arrhythmia)*
• Pneumonia and other acute infections*
• Myocardial infarction*
• Pulmonary embolism*
• Thyrotoxicosis*
• Acute alcohol intoxication ("holiday heart syndrome")Michaud GF, Stevenson WG (2021). "Atrial Fibrillation". N Engl J Med. 384 (4): 353–361. doi:10.1056/NEJMcp2023658. PMID 33431790 .*

Pathophysiology

The pathophysiology of AF involves a complex interplay of triggers, substrate, and modulators that promote initiation and maintenance of the arrhythmia.Nattel S, Harada M (2014). "Atrial Remodeling and Atrial Fibrillation: Recent Advances and Translational Perspectives". J Am Coll Cardiol. 63 (22): 2335–45. doi:10.1016/j.jacc.2014.02.555. PMID 24613319.

Triggers

The landmark observation by Haïssaguerre et al. demonstrated that ectopic firing from myocardial sleeves extending into the pulmonary veins triggers AF. Features of pulmonary vein myocytes that increase vulnerability to ectopy include a higher resting membrane potential, stretch-activated channels, and cross-myofiber orientation patterns.

Substrate

Persistence of AF is due to disease-specific atrial electrophysiological, structural, and histopathological changes that promote electrical reentry and AF continuance. Four principal pathophysiological mechanisms contribute to AF:

1. Electrical remodeling: Perturbations in ion channel expression, including decreased L-type Ca2+ current and increased IK1, lead to shortened, proarrhythmic action potentials. Downregulation of connexins decreases gap junctions, leading to slow heterogeneous atrial conduction and promoting reentry.

1. Structural remodeling: Interstitial fibrosis, myofibroblast activation, collagen deposition, fibrofatty infiltration, and inflammatory infiltrates alter atrial architecture. Atrial cardiomyopathy has been defined as "any complex of structural, architectural, contractile or electrophysiological changes affecting the atria with the potential to produce clinically relevant manifestations."

1. Calcium handling abnormalities: Remodeling increases sarcoplasmic reticulum calcium load and dysfunction of ryanodine receptors, promoting spontaneous diastolic Ca2+ leak and delayed afterdepolarizations, the most likely trigger for AF initiation.

1. Autonomic nervous system changes: Autonomic dysfunction (e.g., with sleep-disordered breathing) alters atrial repolarization and promotes AF.

Upstream Pathways

The renin-angiotensin-aldosterone system (RAAS), activated in hypertension and obesity, promotes vascular smooth muscle constriction, activates fibroblasts (increasing atrial interstitial collagen), and increases reactive oxygen species. Oxidative stress activates calcium-dependent calmodulin kinase II and the NLRP3 inflammasome, contributing to AF pathogenesis. Systemic inflammatory activation has been associated with both postoperative and nonsurgical AF.

The concept of "AF begets AF" describes the auto-reinforcing property whereby AF itself causes further AF-promoting remodeling, making the arrhythmia progressively more difficult to treat over time.

Differentiating Atrial Fibrillation from Other Diseases

AF must be differentiated from other supraventricular tachycardias and irregular rhythms. The key distinguishing feature of AF is the irregularly irregular ventricular response with absence of discrete P waves.Nasir M, Sturts A (2023). "Common Types of Supraventricular Tachycardia: Diagnosis and Management". Am Fam Physician. 107 (6): 631–641. PMID 37327167 .

Arrhythmia	Rhythm Regularity	P Waves / Atrial Activity	Key Distinguishing Features
Atrial fibrillation	Irregularly irregular	Absent; fibrillatory baseline	No discrete P waves; variable R-R intervals
Atrial flutter	Regularly irregular (or regular)	Sawtooth flutter (F) waves, best seen in leads II, III, aVF, V1	Atrial rate typically 240–320 bpm; regular atrial activity
Multifocal atrial tachycardia	Irregularly irregular	≥3 distinct P-wave morphologies	Organized but varying P waves; often associated with COPD
AVNRT	Regular	Often buried in QRS or retrograde P waves	Abrupt onset and termination; responds to adenosine
AVRT	Regular	Retrograde P waves	Accessory pathway; may show delta wave in sinus rhythm (WPW)
Focal atrial tachycardia	Regular	Discrete P waves with isoelectric baseline	P-wave morphology localizes origin
Sinus tachycardia	Regular	Normal P waves	Gradual onset; rate appropriate to physiological stimulus
Ventricular tachycardia	Regular (usually)	AV dissociation	Wide QRS (>120 ms); must be distinguished from AF with aberrant conduction or preexcitation

AF may coexist with atrial flutter, and the two arrhythmias may convert between each other. Atrial flutter may degenerate into AF, and AF may organize into atrial flutter.Fuster V, Rydén LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, Halperin JL, Le Heuzey JY, Kay GN, Lowe JE, Olsson SB, Prystowsky EN, Tamargo JL, Wann S (2006). "ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation". J Am Coll Cardiol. 48 (4): 854–906. doi:10.1016/j.jacc.2006.07.009. PMID 16904574.

Diagnosis

Clinical Presentation

Symptoms of AF include palpitations, dyspnea, chest pain, presyncope, exertional intolerance, and fatigue. Approximately 10% to 40% of patients with AF are asymptomatic. Asymptomatic AF is more common in men (10% vs 3% in women) and older adults (mean age 74 years vs 62 years for symptomatic patients).

Electrocardiographic Diagnosis

The diagnosis of AF is confirmed by identifying irregular atrial activity (fibrillatory waves) without discrete P waves on a 12-lead electrocardiogram or lasting for longer than 30 seconds on a rhythm strip. Diagnostic criteria require:Calkins H, Hindricks G, Cappato R, Kim YH, Saad EB, Aguinaga L, Akar JG, Badhwar V, Brugada J, Camm J, Chen PS, Chen SA, Chung MK, Cosedis Nielsen J, Curtis AB, Davies DW, Day JD, d'Avila A, de Groot N, Di Biase L, Duytschaever M, Edgerton JR, Ellenbogen KA, Ellinor PT, Ernst S, Fenelon G, Gerstenfeld EP, Haines DE, Haissaguerre M, Helm RH, Hylek E, Jackman WM, Jalife J, Kalman JM, Kautzner J, Kottkamp H, Kuck KH, Kumagai K, Lee R, Lewalter T, Lindsay BD, Macle L, Mansour M, Marchlinski FE, Michaud GF, Nakagawa H, Natale A, Nattel S, Okumura K, Packer D, Pokushalov E, Reynolds MR, Sanders P, Scanavacca M, Schilling R, Tondo C, Tsao HM, Verma A, Wilber DJ, Yamane T (2017). "2017 HRS/EHRA/ECAS/APHRS/SOLAECE Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation". Heart Rhythm. 14 (10): e275–e444. doi:10.1016/j.hrthm.2017.05.012. PMID 28506916.

1. "Absolutely" irregular R-R intervals (in the absence of complete atrioventricular block)

1. No distinct P waves on the surface ECG

1. An atrial cycle length (when visible) that is usually less than 200 ms

Classification

• Paroxysmal AF: AF that terminates spontaneously or with intervention within 7 days of onset*
• Persistent AF: Continuous AF sustained beyond 7 days*
• Long-standing persistent AF: Continuous AF of greater than 12 months' duration*
• Permanent AF: AF accepted by the patient and physician, with no further attempts at rhythm control*

Initial Evaluation

Evaluation of patients with newly identified AF should include:

• 12-lead ECG: To confirm diagnosis, assess for other electrical abnormalities (e.g., WPW, left ventricular hypertrophy, conduction disease)*
• Transthoracic echocardiogram: To assess cardiac structure, chamber size, left ventricular function, and valvular pathology*
• Laboratory testing: Complete blood count, basic metabolic panel, thyroid function tests (to exclude hyperthyroidism)*
• Additional testing: Ambulatory ECG monitoring (e.g., Holter monitor, event recorder) for suspected paroxysmal AF; implantable loop recorder for cryptogenic stroke evaluation*
• Routine testing for myocardial ischemia, acute coronary syndrome, or pulmonary embolism should not be performed in the absence of specific signs or symptoms*

Treatment

Management of AF is guided by three pillars: (1) prevention of thromboembolism, (2) rate and/or rhythm control for symptom management, and (3) management of comorbidities and risk factors. The 2024 ESC/EACTS guidelines introduced the AF-CARE framework: [C] Comorbidity and risk factor management, [A] Avoid stroke and thromboembolism, [R] Reduce symptoms by rate and rhythm control, and [E] Evaluation and dynamic reassessment.Rienstra M, Tzeis S, Bunting KV, ", et al. (2024). "Spotlight on the 2024 ESC/EACTS Management of Atrial Fibrillation Guidelines: 10 Novel Key Aspects". Europace. 26 (12): euae298. doi:10.1093/europace/euae298. PMID 39716733 .

Initial Management

• Hemodynamic instability: Urgent synchronized electrical cardioversion is indicated for patients with AF and hemodynamic compromise (e.g., hypotension, acute heart failure, myocardial ischemia).*
• Hemodynamically stable patients: Initial management typically includes rate control and assessment for anticoagulation, with consideration of rhythm control based on individual patient factors.Holder S, Amin P (2024). "Atrial Fibrillation: Common Questions and Answers About Diagnosis and Treatment". Am Fam Physician. 109 (5): 398–404. PMID 38804754 .*

Medical Therapy

Anticoagulation for Stroke Prevention

Patients with AF have an increased risk of stroke that varies widely among individuals. The CHA2DS2-VASc score is the most validated risk stratification tool and assigns points as follows: 1 point each for congestive heart failure/LV dysfunction, hypertension, diabetes mellitus, vascular disease, age 65–74 years, and female sex; 2 points each for age ≥75 years and prior stroke/transient ischemic attack/thromboembolism.

Anticoagulation recommendations:

• CHA2DS2-VASc ≥2 in men (≥3 in women): Oral anticoagulation is recommended (Class I).*
• CHA2DS2-VASc 1 in men (2 in women): Oral anticoagulation is reasonable (Class IIa).*
• CHA2DS2-VASc 0 in men (1 in women): No antithrombotic therapy is recommended.*

Direct oral anticoagulants (DOACs) are recommended over warfarin for most patients with nonvalvular AF. All four DOACs (apixaban, dabigatran, edoxaban, rivaroxaban) demonstrated superiority or noninferiority to warfarin for prevention of stroke or systemic embolism. DOACs are associated with significantly lower risks of intracranial hemorrhage compared with warfarin. Apixaban has demonstrated a favorable effectiveness-safety profile, with no significant increase in gastrointestinal bleeding compared with warfarin.Zhang J, Wang X, Liu X, Gao L, Chen Y, Yang W (2021). "Comparative Effectiveness and Safety of Direct Acting Oral Anticoagulants in Nonvalvular Atrial Fibrillation for Stroke Prevention: A Systematic Review and Meta-Analysis". Eur J Epidemiol. 36 (8): 793–812. doi:10.1007/s10654-021-00751-7. PMID 33993379 .

Warfarin remains indicated for patients with moderate to severe mitral stenosis or a mechanical heart valve.

Aspirin alone should not be used for stroke prevention in AF, as it is associated with poorer efficacy and is not recommended.

Rate Control

Rate control aims to reduce the ventricular rate to alleviate symptoms and prevent tachycardia-mediated cardiomyopathy.

Agent Class	Examples	Key Considerations
Beta blockers	Metoprolol, atenolol, carvedilol	First-line; avoid in decompensated heart failure (except carvedilol)
Nondihydropyridine calcium channel blockers	Diltiazem, verapamil	First-line when LVEF >40%; contraindicated in moderate-severe LV systolic dysfunction and decompensated HF
Digoxin	Digoxin	Second-line; useful in combination with beta blockers or calcium channel blockers; less effective during exercise; monitor levels especially in elderly and renal impairment
Amiodarone	Amiodarone	Reserved for critically ill or decompensated HF when other agents are ineffective or contraindicated

Heart rate targets: A resting heart rate 100 to 110 bpm is generally recommended for hemodynamically stable patients without HF. A stricter target of 80 bpm may be appropriate for patients with LV dysfunction, symptoms, or suspected tachycardia-mediated cardiomyopathy. The RACE II trial demonstrated that lenient rate control (110 bpm at rest) was noninferior to strict rate control in patients with permanent AF and preserved LV function.

Rhythm Control

Rhythm control aims to restore and maintain sinus rhythm to improve symptoms, quality of life, and potentially cardiovascular outcomes. The EAST-AFNET 4 trial demonstrated that early rhythm control (within 12 months of diagnosis) was associated with significant reductions in cardiovascular death (1.0% vs 1.3% per year; HR 0.72 [95% CI, 0.52–0.98]) and stroke (0.6% vs 0.9% per year; HR 0.65 [95% CI, 0.44–0.97]) compared with usual care.Lane DA, Andrade JG, Arbelo E, Boriani G, Brandes A, Calkins H, Chiang CE, Chung MK, Crijns H, Eckardt L, Fauchier L, Freedman B, Gerber L, Healey JS, Heidbuchel H, Hendriks J, Hindricks G, Joglar JA, Kääb S, Kirchhof P, Kotalczyk A, Lip G, Linz D, Lopes RD, Lubitz SA, Mairesse S, Metzner A, Nattel S, Potpara TS, Proietti M, Rienstra M, Sanders P, Schnabel RB, Svennberg E, Turakhia MP, Van Gelder IC, Verma A, Willems S (2026). "Atrial Fibrillation". Lancet. 407 (10532): 1000–1013. doi:10.1016/S0140-6736(25)02166-X. PMID 41794418 .

Antiarrhythmic drugs (AADs):

Drug	Class	Key Indications / Considerations
Flecainide	IC	Paroxysmal AF without structural heart disease; requires concomitant AV nodal blocking agent
Propafenone	IC	Paroxysmal AF without structural heart disease; requires concomitant AV nodal blocking agent
Amiodarone	III	Effective across AF subtypes; safe in HFrEF; long-term toxicity (pulmonary, thyroid, hepatic, neurological)
Dofetilide	III	Safe in HFrEF; requires in-hospital initiation with QTc monitoring; doubles chance of maintaining sinus rhythm at 1 year vs placebo
Dronedarone	III	Reduces cardiovascular hospitalization; contraindicated in NYHA Class III–IV HF and permanent AF
Sotalol	III	Effective for AF maintenance; increases mortality in patients with HF; requires QTc monitoring

Cardioversion: Synchronized electrical cardioversion is more successful than pharmacological cardioversion alone and can be used as initial treatment or after a medication trial. Anticoagulation is recommended before cardioversion and for at least 4 weeks after. If a thrombus is found on transesophageal echocardiogram, cardioversion should be delayed for at least 3 weeks with anticoagulation initiated.

Procedural / Surgical Therapy

Catheter Ablation

Catheter ablation of AF, primarily through pulmonary vein isolation, is an established treatment for symptomatic AF. The cornerstone of the procedure is electrical isolation of the pulmonary veins from the left atrium.

Indications:

• First-line therapy: Catheter ablation is a first-line rhythm control option for suitable patients with symptomatic paroxysmal AF (Class I) to improve symptoms and slow progression to persistent AF.*
• After AAD failure: Catheter ablation is recommended for symptomatic paroxysmal AF refractory or intolerant to at least one Class I or III AAD (Class I, LOE A).*
• Persistent AF after AAD failure: Catheter ablation is reasonable (Class IIa).*
• Heart failure with reduced ejection fraction: Catheter ablation is recommended for patients with AF and HFrEF to improve quality of life, LV systolic function, and cardiovascular outcomes (Class I).*

Outcomes: AF recurs in up to 40% of patients after initial ablation and can be treated with repeat ablation. Success rates are highest for paroxysmal AF (60–90%) and lower for persistent AF (~50%). Younger patients with minimal atrial enlargement and less myocardial fibrosis have the best outcomes.

Left Atrial Appendage Occlusion

Left atrial appendage occlusion (LAAO) is a nonpharmacologic strategy for stroke prevention in patients with AF. Approximately 90% of thrombi in patients with nonvalvular AF originate from the left atrial appendage.Seiffge DJ, Cancelloni V, Räber L, Bonati LH, Kaesmacher J, Mattle HP, Meinel TR, Fischer U, Engelter ST, De Marchis GM (2024). "Secondary Stroke Prevention in People With Atrial Fibrillation: Treatments and Trials". Lancet Neurol. 23 (4): 404–417. doi:10.1016/S1474-4422(24)00037-1. PMID 38508836 .

• Percutaneous LAAO (e.g., WATCHMAN, Amulet* ### Atrial Fibrillation

devices) may be considered in patients with AF at increased risk of stroke who have contraindications to long-term anticoagulation (Class IIb, LOE B-NR).

• The PROTECT AF and PREVAIL trials compared the WATCHMAN device with warfarin. A 5-year patient-level meta-analysis demonstrated similar efficacy for stroke prevention and reduced rates of major bleeding, hemorrhagic stroke (HR 0.20; 95% CI, 0.21–0.75), and all-cause mortality (HR 0.73; 95% CI, 0.45–0.98) with LAAO compared with warfarin.Reddy VY, Doshi SK, Kar S, Gibson DN, Price MJ, Huber K, Horton RP, Buchbinder M, Neuzil P, Gordon NT, Holmes DR (2017). "5-Year Outcomes After Left Atrial Appendage Closure: From the PREVAIL and PROTECT AF Trials". J Am Coll Cardiol. 70 (24): 2964–2975. doi:10.1016/j.jacc.2017.10.021. PMID 29103847.*
• The CHAMPION-AF trial (2026) compared LAAO with the WATCHMAN FLX device versus DOAC therapy in patients eligible for oral anticoagulation. LAAO was noninferior to DOAC therapy for the composite of cardiovascular death, stroke, or systemic embolism at 3 years (5.7% vs 4.8%; HR 1.20 [95% CI, 0.87–1.66]; P0.001 for noninferiority) and was associated with significantly lower non-procedure-related bleeding (10.9% vs 19.0%; HR 0.55 [95% CI, 0.45–0.67]; P0.001 for superiority).Doshi SK, Kar S, Nair DG, et al. (2026). "Left Atrial Appendage Closure or Anticoagulation for Atrial Fibrillation". N Engl J Med. doi:10.1056/NEJMoa2517213.
• Both the WATCHMAN (Boston Scientific) and Amulet (Abbott) devices have received FDA approval. Current data suggest both devices offer similar efficacy and safety for LAAO.Frazzetto M, Sanfilippo C, Costa G, et al. (2024). "Watchman vs. Amulet for Left Atrial Appendage Closure: Current Evidence and Future Perspectives". J Clin Med. 13 (16): 4651. doi:10.3390/jcm13164651. PMID 39200792 .*

Surgical Approaches

• Surgical left atrial appendage occlusion: The LAAOS III trial demonstrated that surgical LAA closure performed during cardiac surgery for other indications (e.g., coronary artery bypass grafting, valve replacement) reduced the risk of ischemic stroke and systemic embolism in patients who continued to receive chronic oral anticoagulation.*
• Surgical maze procedure: The Cox-Maze IV procedure, performed as a stand-alone or concomitant procedure during other cardiac surgery, creates a series of atrial lesions to interrupt reentrant circuits. It is most commonly performed as an adjunctive procedure during mitral valve surgery.*

Long-Term Management

Lifestyle and Risk Factor Modification

Comprehensive lifestyle and risk factor modification (LRFM) is a cornerstone of AF management across all stages. The 2023 ACC/AHA/ACCP/HRS Guideline provides Class I recommendations for the following:

• Weight management: In overweight and obese patients with AF, weight loss of ≥10% is associated with a dose-dependent reduction in AF burden and improved freedom from AF. The LEGACY trial demonstrated that sustained weight loss of ≥10% was associated with a 6-fold greater probability of arrhythmia-free survival compared with those who lost 3% of body weight. Initial goals include targeting BMI ≤27 kg/m2.Chung MK, Eckhardt LL, Chen LY, Ahmed HM, Gopinathannair R, Joglar JA, Noseworthy PA, Pack QR, Sanders P, Trulock KM (2020). "Lifestyle and Risk Factor Modification for Reduction of Atrial Fibrillation: A Scientific Statement From the American Heart Association". Circulation. 141 (16): e750–e772. doi:10.1161/CIR.0000000000000748. PMID 32886820 .*
• Physical activity: At least 150 min/week of moderate-intensity or 75 min/week of vigorous-intensity physical activity is recommended. Sedentary behavior and chronic extreme endurance exercise are both associated with increased AF risk.*
• Alcohol moderation or abstinence: Alcohol increases AF risk in a dose-dependent manner. The ACC/AHA guideline recommends ≤1 standard drink per day; the ESC recommends ≤3 standard drinks per week.*
• Smoking cessation*
• Blood pressure control: Intensive blood pressure control (systolic BP 120 mmHg) was associated with lower AF risk (HR 0.74 [95% CI, 0.56–0.98]) in secondary analysis of randomized trial data.*
• Obstructive sleep apnea management: Screening for and treatment of OSA with continuous positive airway pressure (CPAP) reduces AF episodes.*
• Diabetes management: SGLT2 inhibitors have been associated with reduced AF risk (RR 0.82 [95% CI, 0.72–0.93]) in a meta-analysis of 20 randomized trials.*

Atrioventricular Nodal Ablation

Atrioventricular node ablation (AVNA) with permanent pacemaker implantation provides effective rate control in patients with AF and persistently rapid ventricular response refractory to rate-control medications who are not candidates for or in whom rhythm control has been unsuccessful (Class IIa, LOE B-R).

• After AVNA, initial pacemaker lower rate programming should be 80 to 90 bpm to reduce the risk of sudden cardiac death (Class I).*
• In patients with reduced ejection fraction undergoing AVNA, biventricular pacing (cardiac resynchronization therapy) should be considered over right ventricular pacing to reduce the risk of pacing-induced cardiomyopathy.*
• AVNA renders patients pacemaker-dependent and should be considered only after other options have been exhausted.*

Special Populations

Heart Failure

AF and heart failure frequently coexist and share a bidirectional relationship. AF is associated with a 5-fold risk of HF, and HF promotes AF through atrial stretch, fibrosis, and neurohormonal activation.

• Rate control: Beta blockers are first-line for rate control in HF. Nondihydropyridine calcium channel blockers (diltiazem, verapamil) are contraindicated in patients with HFrEF. Digoxin may be added as a second-line agent. Amiodarone may be used for rate control in decompensated HF when other agents are ineffective.*
• Rhythm control: Amiodarone and dofetilide are the only antiarrhythmic drugs considered safe in patients with HFrEF. Dronedarone is contraindicated in NYHA Class III–IV HF.*
• Catheter ablation: Catheter ablation is recommended for patients with AF and HFrEF to improve quality of life, LV systolic function, and cardiovascular outcomes (Class I). The CASTLE-AF trial demonstrated that catheter ablation in patients with AF and HFrEF was associated with significantly lower rates of death or hospitalization for worsening HF compared with medical therapy.*

Hypertrophic Cardiomyopathy

AF occurs in nearly half of patients with hypertrophic cardiomyopathy (HCM) and is associated with substantial stroke risk.Rowin EJ, Link MS, Maron MS, Maron BJ (2023). "Evolving Contemporary Management of Atrial Fibrillation in Hypertrophic Cardiomyopathy". Circulation. 148 (22): 1797–1811. doi:10.1161/CIRCULATIONAHA.123.065037. PMID 38011245 .

• Anticoagulation: The CHA2DS2-VASc score is not informative in HCM, as patients with low scores remain at substantial stroke risk. A low threshold of one or more symptomatic AF episodes is sufficient to recommend anticoagulation with DOACs or warfarin.Ommen SR, Ho CY, Asif IM, et al. (2024). "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy". J Am Coll Cardiol. 83 (23): 2324–2405. doi:10.1016/j.jacc.2024.02.014.
• Rhythm control: Antiarrhythmic drugs including sotalol, disopyramide, dofetilide, and amiodarone have been used safely. Catheter ablation is an option but is less effective than in the general AF population, with a 2-fold higher risk of relapse and more frequent need for repeat procedures.
• Surgical ablation: In patients with HCM undergoing surgical myectomy, concomitant biatrial Cox-Maze IV can reduce AF recurrences (approximately 70% freedom from AF at 5 years).*

Wolff-Parkinson-White Syndrome and Preexcitation

AF with rapid anterograde conduction over an accessory pathway (preexcited AF) is a potentially life-threatening condition that can degenerate into ventricular fibrillation.

• Hemodynamic instability: Urgent electrical cardioversion is recommended (Class I).*
• Hemodynamically stable: Intravenous ibutilide or procainamide is recommended for pharmacological cardioversion (Class I).*
• Catheter ablation: Ablation of the accessory pathway is recommended (Class I).*
• Contraindicated agents: AV nodal blocking agents (verapamil, diltiazem, amiodarone, digoxin, adenosine, beta blockers) are contraindicated in preexcited AF due to the risk of precipitating VF or hemodynamic deterioration (Class III: Harm).*

Pregnancy

AF during pregnancy is uncommon but is associated with increased maternal mortality (OR 13.13 [95% CI, 7.77–22.21]).

• Cardioversion: Direct current cardioversion is safe for both mother and fetus and should be performed in the same manner as in nonpregnant patients (Class I).Joglar JA, Kapa S, Saarel EV, et al. (2023). "2023 HRS Expert Consensus Statement on the Management of Arrhythmias During Pregnancy". Heart Rhythm. 20 (10): e175–e264. doi:10.1016/j.hrthm.2023.05.017.*
• Rate control: Beta blockers (propranolol, metoprolol) and digoxin are first-line agents. Atenolol should be avoided due to concerns about intrauterine growth retardation.*
• Rhythm control: Flecainide and sotalol have a long record of safety in pregnancy. Amiodarone is generally avoided due to fetal toxicity (goiter, neurodevelopmental abnormalities, bradycardia).*
• Anticoagulation: DOACs are contraindicated during pregnancy. Low-molecular-weight heparin or warfarin (if dose ≤5 mg/day) may be used depending on trimester and individual risk assessment through shared decision-making.*

Older Adults (≥75 Years)

Older adults have the highest prevalence of AF and the greatest absolute benefit from anticoagulation for stroke prevention. However, they also have increased bleeding risk. DOACs are preferred over warfarin in older adults due to lower rates of intracranial hemorrhage. Dose adjustments are required for some DOACs based on age, weight, and renal function (e.g., apixaban 2.5 mg twice daily if ≥2 of: age ≥80 years, weight ≤60 kg, or serum creatinine ≥1.5 mg/dL).Volgman AS, Nair G, Lyubarova R, et al. (2022). "Management of Atrial Fibrillation in Patients 75 Years and Older: JACC State-of-the-Art Review". J Am Coll Cardiol. 79 (2): 166–179. doi:10.1016/j.jacc.2021.10.037. PMID 35027110 .

Frailty, fall risk, polypharmacy, and cognitive impairment should be considered in treatment decisions, but advanced age alone should not be a reason to withhold anticoagulation.

Prevention

Primary Prevention

Primary prevention of AF focuses on addressing modifiable risk factors before AF develops (Stage 1 and Stage 2 patients):

• Maintenance of ideal body weight (BMI ≤25 kg/m2) or weight loss if overweight/obese (Class I)*
• Regular moderate-intensity physical activity (≥150 min/week) (Class I)*
• Smoking cessation (Class I)*
• Alcohol moderation (≤1 standard drink/day) or abstinence (Class I)*
• Optimal blood pressure control per guideline-directed therapy (Class I)*
• Diabetes management (Class I)*
• Screening and treatment of obstructive sleep apnea (Class I)*

Secondary Prevention

In patients with established AF, comprehensive risk factor management reduces AF burden, improves outcomes of rhythm control strategies, and may promote regression from persistent to paroxysmal AF. The ARREST-AF study demonstrated that aggressive risk factor management significantly reduced AF frequency, duration, symptoms, and symptom severity compared with usual care.

Prognosis

AF is associated with significant morbidity and mortality:

• Mortality: AF is associated with a 1.5- to 2-fold increased risk of death; the mortality risk may be higher in women than in men. In Medicare beneficiaries, the most frequent outcome in the 5 years after AF diagnosis was death (19.5% at 1 year; 48.8% at 5 years).*
• Stroke: AF is associated with a 2.4-fold risk of stroke. AF-related strokes tend to be more severe and disabling than strokes from other causes.*
• Heart failure: AF is associated with a 5-fold risk of heart failure.*
• Myocardial infarction: AF is associated with a 1.5-fold risk of myocardial infarction.*
• Sudden cardiac death: AF is associated with a 2-fold risk of sudden cardiac death.*
• Cognitive impairment and dementia: AF is associated with a 1.5-fold risk of cognitive impairment or dementia, independent of clinical stroke. A meta-analysis found that AF was significantly associated with cognitive impairment independent of stroke history (RR 1.34 [95% CI, 1.13–1.58]) and with dementia (RR 1.38 [95% CI, 1.22–1.56]). Oral anticoagulation may reduce the risk of dementia by approximately 40% to 60%.Diener HC, Hart RG, Koudstaal PJ, Lane DA, Lip G (2019). "Atrial Fibrillation and Cognitive Function: JACC Review Topic of the Week". J Am Coll Cardiol. 73 (5): 612–619. doi:10.1016/j.jacc.2018.10.077. PMID 30732716. *
• Chronic kidney disease: AF is associated with a 1.6-fold risk of chronic kidney disease.*
• Quality of life: AF significantly impairs quality of life, with symptoms including palpitations, fatigue, dyspnea, and exercise intolerance.*

Prognosis is improved with appropriate anticoagulation, rhythm or rate control, and comprehensive risk factor management. Early rhythm control (within 12 months of diagnosis) has been associated with improved cardiovascular outcomes.

Indications for Referral

Referral to a cardiologist or cardiac electrophysiologist should be considered in the following situations:

• New-onset AF requiring evaluation for underlying etiology*
• Symptomatic AF refractory to initial rate-control therapy*
• Consideration of rhythm control strategy, including antiarrhythmic drug initiation (particularly dofetilide, which requires in-hospital initiation)*
• Evaluation for catheter ablation or surgical ablation*
• AF with Wolff-Parkinson-White syndrome or preexcitation*
• AF in the setting of hypertrophic cardiomyopathy or other complex structural heart disease*
• AF with heart failure with reduced ejection fraction*
• Difficulty with anticoagulation decisions (e.g., high bleeding risk, contraindications to oral anticoagulation, consideration of left atrial appendage occlusion)*
• AF in pregnancy*
• Young patients (60 years) with AF and no identifiable risk factors ("lone atrial fibrillation")*
• Suspected tachycardia-mediated cardiomyopathy*
• Consideration of atrioventricular node ablation and pacemaker implantation*

References

References