Established atrial fibrillation

Established atrial fibrillation (AF) is clinically diagnosed 'paroxysmal', 'persistent', 'long-standing persistent', and 'permanent' chaotic and irregular atrial arrhythmia.

Prevalence increases progressively with age.

Patients frequently have co-existing cardiac or non-cardiac conditions, such as hypertension, coronary artery disease, valvular disease, heart failure, obesity, sleep apnoea, or pulmonary disease.

Causes significant morbidity (e.g., palpitations, dyspnoea, angina, dizziness or syncope, and features of heart failure, tachycardia-induced cardiomyopathy, or stroke) and death. Many patients are asymptomatic or have symptoms that are less specific for cardiac arrhythmias, such as mild dementia or silent strokes.

ECG shows absent P waves, presence of fibrillatory waves, and irregularly irregular QRS complexes.

Treatment strategy depends on the severity of symptoms, the duration of AF, and the presence of comorbid conditions. Treatment involves correction of the abnormal rate, or rate plus rhythm, along with anticoagulation in high-risk patients.

Risks and benefits of a chosen therapy, such as rate control or rhythm control strategies utilising beta-blockers, non-dihydropyridine calcium-channel blockers, digoxin, anti-arrhythmic agents, catheter-based or surgical ablation for pulmonary vein isolation and left atrial substrate modification, pacemakers, and ablation of the atrioventricular node need to be weighed based on multiple clinical factors to optimise patient outcome.

AF is a supraventricular tachycardia with uncoordinated atrial activation and ineffective atrial contraction.[1]Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on clinical practice guidelines. Circulation. 2024 Jan 2;149(1):e1-156. https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000001193?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org http://www.ncbi.nlm.nih.gov/pubmed/38033089?tool=bestpractice.com [2]Hindricks G, Potpara T, Dagres N, et al. 2020 ESC guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2021 Feb 1;42(5):373-498. https://academic.oup.com/eurheartj/article/42/5/373/5899003 http://www.ncbi.nlm.nih.gov/pubmed/32860505?tool=bestpractice.com ​ Diagnosis requires ECG documentation. ECG characteristics include irregularly irregular RR intervals (where atrioventricular conduction is present); absence of distinct P waves; irregular atrial activations.[1]Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on clinical practice guidelines. Circulation. 2024 Jan 2;149(1):e1-156. https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000001193?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org http://www.ncbi.nlm.nih.gov/pubmed/38033089?tool=bestpractice.com ​​[2]Hindricks G, Potpara T, Dagres N, et al. 2020 ESC guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2021 Feb 1;42(5):373-498. https://academic.oup.com/eurheartj/article/42/5/373/5899003 http://www.ncbi.nlm.nih.gov/pubmed/32860505?tool=bestpractice.com ​[Figure caption and citation for the preceding image starts]: Atrial fibrillation: P waves are not discernible; the ventricular (QRS complexes) rate is irregularly irregularFrom the collection of Dr Arti N. Shah [Citation ends].​​ It is primarily defined based on duration and frequency of episodes; therefore, established AF could be paroxysmal, persistent, or permanent, and even new onset if detected for the first time.

For details on new-onset AF, please see New-onset atrial fibrillation.

Clinical AF is symptomatic or asymptomatic AF that is documented by surface ECG.

Subclinical AF is detection of the arrhythmia in individuals who do not have symptoms attributable to AF and in whom there is no previous ECG documenting AF. This includes AF detected by implantable or wearable devices.

Atrial high-rate episodes (AHREs) are defined as events detected by cardiac implantable electronic devices that exceed the programmed detection rate limit set by the device and can be used to define the burden of disease in established AF. AHREs require visual inspection to confirm AF and exclude other atrial arrhythmias, artefact, or oversensing.[1]Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on clinical practice guidelines. Circulation. 2024 Jan 2;149(1):e1-156. https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000001193?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org http://www.ncbi.nlm.nih.gov/pubmed/38033089?tool=bestpractice.com ​​[2]Hindricks G, Potpara T, Dagres N, et al. 2020 ESC guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2021 Feb 1;42(5):373-498. https://academic.oup.com/eurheartj/article/42/5/373/5899003 http://www.ncbi.nlm.nih.gov/pubmed/32860505?tool=bestpractice.com ​