# Atrial fibrillation (AF) Condition · id `cardio:atrial-fibrillation` · Cardiovascular Atlas · release `f6f6f1b6f50379ed` (public) > General information from published sources, not medical advice, and not reviewed by clinicians. Check the cited source before relying on anything here. The atlas's own text and curation may be reused under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0, https://creativecommons.org/licenses/by-nc/4.0/): credit the atlas, and do not use it commercially. See the atlas About page. Text quoted from a source stays under that source's own terms, given as the source's reuse\_basis. The atlas's reuse terms do not cover it. The downloads list each quotation with its source in third\_party\_quotations. Also called: Atrial fibrillation; AFib; A-fib Browse, organ or system: Heart Browse, condition area: Stroke; Heart rhythm problems ## In plain language Atrial fibrillation, also called AF, A-fib or AFib, is among the commonest arrhythmias. The heartbeat becomes irregular and can speed up well beyond normal. Because blood can collect in the heart, clots can form, and a clot can cause a stroke. Some people have no symptoms, which makes the condition difficult to spot. NHLBI counts over 2 million US adults with it, and the chance of developing it grows with age. ## Technical summary Hub for the anticoagulant, device and detection records. MeSH descriptor D001281 (Atrial Fibrillation). NHLBI attributes most cases to damage to the heart's muscle tissue or electrical system, usually from other disease; it names coronary heart disease and raised blood pressure, and lists high blood pressure among the conditions that raise the risk. Treatment per NHLBI includes lifestyle changes, medicines (blood thinners, rate control, rhythm control) and procedures. The text rests on NHLBI and MedlinePlus patient pages. ## Claims, with the population each applies to ## Context: Adults with atrial fibrillation, in general terms (NHLBI and MedlinePlus patient pages) Recipient: Adult; Population: People with atrial fibrillation, described in general terms. NHLBI puts the number of US adults with atrial fibrillation above 2 million and says the chance of developing it grows with age. The pages do not describe a study population.; Care setting: Not applicable (patient information pages, not a study); Geography: Not stated in the pages for most statements; the prevalence sentence refers to the United States; Life stage: Adults in general. NHLBI describes atrial fibrillation as uncommon in children.; Follow-up: Not applicable (patient information pages) ### NHLBI explains that in atrial fibrillation blood can collect in the heart, which makes clots more likely to form, and that clots can cause strokes and other problems. It adds that atrial fibrillation left untreated can have serious, even life-threatening, consequences, and it names stroke and heart failure. MedlinePlus says atrial fibrillation can put a person at risk for stroke and other heart conditions. Neither page gives a number for how much atrial fibrillation raises the risk. - Category: Description - Evidence stage: Evidence synthesis - Certainty: Certainty not assessed - Applies to: Recipient: Adult; Population: People with atrial fibrillation, described in general terms. NHLBI puts the number of US adults with atrial fibrillation above 2 million and says the chance of developing it grows with age. The pages do not describe a study population.; Care setting: Not applicable (patient information pages, not a study); Geography: Not stated in the pages for most statements; the prevalence sentence refers to the United States; Life stage: Adults in general. NHLBI describes atrial fibrillation as uncommon in children.; Follow-up: Not applicable (patient information pages) - Limitations: Patient information pages, not a study. They give no risk estimate and do not say for whom the risk is higher. The NHLBI page is dated 30 November 2022; the MedlinePlus page date was not read. - Last checked: 2026-10-14 - Sources: 1. Supports: Atrial Fibrillation: What Is Atrial Fibrillation? (NHLBI) (Webpage, edition Page as fetched on 2026-10-14, with the line Last updated on November 30, 2022.) Locator: Page body, paragraph 2. Retrieved 2026-10-14T18:19:49Z. Source state: Current. Snapshot hash: b64d9b1406c4b990086b6d55055c216af16abf1f9606593924807e1d6f07c0d9. How it applies: NHLBI explains how clots form and can lead to stroke. 2. Supports: Atrial Fibrillation: What Is Atrial Fibrillation? (NHLBI) (Webpage, edition Page as fetched on 2026-10-14, with the line Last updated on November 30, 2022.) Locator: Page body, paragraph 2 (passage 2). Retrieved 2026-10-14T18:19:49Z. Source state: Current. Snapshot hash: b64d9b1406c4b990086b6d55055c216af16abf1f9606593924807e1d6f07c0d9. How it applies: NHLBI names stroke and heart failure as complications of untreated atrial fibrillation. 3. Supports: Atrial Fibrillation | AFib (MedlinePlus) (Webpage, edition Page as fetched on 2026-10-14.) Locator: Summary, What is atrial fibrillation (AFib)?. Retrieved 2026-10-14T18:19:51Z. Source state: Current. Snapshot hash: 05dd4474eec5ceb20edfbb11319991d0352ea39610939491e482a963d33c7a67. How it applies: MedlinePlus says atrial fibrillation can put a person at risk for stroke. 4. Background: Atrial Fibrillation: What Is Atrial Fibrillation? (NHLBI) (Webpage, edition Page as fetched on 2026-10-14, with the line Last updated on November 30, 2022.) Locator: Page body, paragraph 1. Retrieved 2026-10-14T18:19:49Z. Source state: Current. Snapshot hash: b64d9b1406c4b990086b6d55055c216af16abf1f9606593924807e1d6f07c0d9. How it applies: The page says how many US adults have atrial fibrillation. ## Connected pages - AF is a type of arrhythmia: Arrhythmia (heart rhythm problems) (`cardio:arrhythmia`) - NHLBI: atrial fibrillation can bring on a stroke; no risk figure given: Stroke (`core:stroke`) [a claim, not a settled fact; see claim `cardio:claim-af-raises-stroke-risk` and its context] - High blood pressure is among the conditions that raise the risk (NHLBI): Hypertension (high blood pressure) (`core:hypertension`) - Filed under this front: Medicines (`cardio:front-medicines`) - Related to: MedlinePlus (`core:medlineplus`) - Related to: AF that causes no symptoms is hard to diagnose (`cardio:bottleneck-undiagnosed-af`) - Related to: Stroke prevention in atrial fibrillation (`cardio:pathway-af-stroke-prevention`) - Evaluated for this: Apixaban (`cardio:apixaban`) [a claim, not a settled fact; see claim `cardio:claim-aristotle-apixaban-vs-warfarin` and its context] - Evaluated for this: Dabigatran (`cardio:dabigatran`) [a claim, not a settled fact; see claim `cardio:claim-re-ly-dabigatran-vs-warfarin` and its context] - Evaluated for this: Rivaroxaban (`cardio:rivaroxaban`) [a claim, not a settled fact; see claim `cardio:claim-rocket-af-rivaroxaban-vs-warfarin` and its context] - Evaluated for this: Rhythm control for AF (medicines or catheter ablation) (`cardio:af-rhythm-control`) [a claim, not a settled fact; see claim `cardio:claim-early-rhythm-control-east-afnet-4` and its context] - Evaluated for this: Blood thinners (oral anticoagulants) to prevent stroke in AF (`cardio:oral-anticoagulation`) [a claim, not a settled fact; see claim `cardio:claim-oral-anticoagulation-prevents-stroke-in-af` and its context] - Evaluated for this: WATCHMAN left atrial appendage closure device (`cardio:watchman`) [a claim, not a settled fact; see claim `cardio:claim-protect-af-watchman-vs-warfarin` and its context] - Investigated in: Apple Heart Study (`cardio:apple-heart-study`) - Investigated in: ARISTOTLE (`cardio:aristotle`) - Investigated in: PROTECT AF (`cardio:protect-af`) - Investigated in: RE-LY (`cardio:re-ly`) - Investigated in: ROCKET AF (`cardio:rocket-af`) - Evaluated for this: Smartwatch irregular-pulse detection (`cardio:wearable-rhythm-detection`) [a claim, not a settled fact; see claim `cardio:claim-apple-heart-study-alerts` and its context] ## Provenance Content hash: 7463a6c969088cecf3b21819dbdd2b4b0853ee05b8be084919f2b30ad5f604d1 Last substantive edit: 2026-10-14 Evidence last checked: 2026-10-14