Draft Recommendation Statement
Screening for Atrial Fibrillation
April 20, 2021
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
- Update in Progress for Screening for Atrial Fibrillation
|Asymptomatic adults age 50 years and older||The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for atrial fibrillation (AF). See the "Practice Considerations" section for additional information regarding the I statement.||I|
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
AF is the most common arrhythmia. The prevalence of AF increases with age, from less than 0.2% in adults younger than age 55 years to about 10% in those age 85 years or older, with a higher prevalence in men than in women.1 AF is a major risk factor for ischemic stroke, increasing risk of stroke by as much as 5-fold.2 Approximately 20% of patients who have a stroke associated with AF are first diagnosed with AF at the time of the stroke or shortly thereafter.3-5
USPSTF Assessment of Magnitude of Net Benefit
The USPSTF concludes that evidence is lacking, and the balance of benefits and harms of screening for AF in asymptomatic adults cannot be determined (Table).
Refer to the Table for more information on the USPSTF recommendation rationale and assessment. For more details on the methods the USPSTF uses to determine the net benefit, see the USPSTF Procedure Manual.6
Patient Population Under Consideration
This recommendation applies to adults age 50 years and older without a diagnosis of or symptoms of AF.
Clinical AF is an atrial tachyarrhythmia that has traditionally been defined by documentation of the arrhythmia on a standard surface, and typically 12-lead, electrocardiogram. It can be persistent or paroxysmal and symptomatic or asymptomatic. As implantable cardiac devices and the use of portable or wearable cardiac monitoring devices have become more common, a new category of AF, called subclinical AF, has emerged. Subclinical AF refers to episodes of asymptomatic AF detected by intracardiac, implantable, or wearable monitors.7,8 The duration of subclinical AF can vary, ranging from a few seconds to more than 24 hours.8 AF burden refers to the amount or percentage of time that is spent in AF. AF burden is often described as low or high, although there is no exact definition or consensus about what constitutes low vs. high AF burden. Clinical AF is known to increase stroke risk,2 but the stroke risk associated with subclinical AF, and particularly low-burden or short-duration AF, is less understood.8,9
Several technologies have been proposed for screening for AF. Electrocardiography (ECG) records the electrical activity of the heart and can be performed using 12 leads, fewer than 12 leads, or a single lead. Several other medical devices (e.g., automated blood pressure cuffs or pulse oximeters) have been designed with algorithms to detect an irregular heartbeat, which may or may not be AF. There are also several consumer-oriented devices, such as smartwatches and smartphone apps, that aim to detect an irregular heart rhythm using ECG technology or photoplethysmography.10
Different intensities (e.g., frequencies, intervals, and durations) of screening for AF are also being studied. Screening can be performed once; for example, by using ECG or a device with an AF detection algorithm at a clinician visit. Screening can also be performed intermittently on multiple occasions; for example, by having a patient briefly record their heart rhythm using a portable device several times a day or several times a week for a period of time, or continuously (e.g., by having a patient wear a portable monitoring device for several days or weeks). The USPSTF categorizes these as one-time screening strategies, intermittent screening strategies, and continuous screening strategies. Continuous screening strategies yield the longest overall duration of screening. Intermittent or continuous screening may be more likely to detect AF but also may be more likely to detect paroxysmal AF that occurs infrequently or is of short duration.9
Treatment or Intervention
Treatment of AF generally has two components—managing symptomatic arrhythmia and preventing stroke. Symptomatic arrhythmia can be managed by controlling the heart rate to minimize symptoms (usually through medication) or by restoring a normal rhythm. Methods for restoring normal rhythm include electrical or pharmacologic cardioversion and surgical or catheter ablation.
To reduce the risk of stroke, anticoagulants are used. Oral anticoagulants include warfarin (a vitamin K antagonist) and target-specific anticoagulants, also known as direct oral anticoagulants.11 In general, guidelines recommend anticoagulant therapy for persons at high risk of stroke.12,13 It is important to note that stroke risk stratiﬁcation instruments (e.g., CHA2DS2-VASc) were developed from populations of patients with clinically diagnosed, and not screen-detected, AF.9
Suggestions for Practice Regarding the I Statement
Potential Preventable Burden
AF is the most common type of cardiac arrhythmia. In the United States, estimates of the prevalence of clinical AF ranged from 2.7 to 6.1 million in 2010.14 The prevalence of AF is highly correlated with age. Its prevalence increases from 0.2% among adults younger than age 55 years to 10% among those age 85 years or older.1 Additional risk factors for AF include diabetes, previous cardiothoracic surgery, smoking, prior stroke, underlying heart disease, hypertension, sleep apnea, obesity, alcohol/drug use, ECG features such as left ventricular hypertrophy and left atrial enlargement, and hyperthyroidism.15 The primary rationale for screening for AF in asymptomatic persons is to initiate oral anticoagulant medications in persons at sufficiently high risk to prevent a thromboembolic event.
Patients with clinical AF not receiving anticoagulant therapy have an approximately 5-fold increased risk of stroke,2 and strokes associated with AF tend to be more severe than strokes attributed to other causes.16 AF does not always cause symptoms, and for approximately 20% of patients who have a stroke associated with AF, stroke is the first sign that they have the condition.17 However, the stroke risk associated with subclinical AF, and particularly subclinical AF of shorter duration (less than several to 24 hours) or lower burden, as might be detected by some screening approaches, is uncertain, and the duration of subclinical AF that might warrant anticoagulation is unclear.8,9
The performance of ECG or use of portable or wearable rhythm monitoring devices itself is not associated with significant harm, although abnormal test results may cause anxiety. Misinterpretation of a screening test result may lead to misdiagnosis and unnecessary treatment. Treatment of AF can include anticoagulant therapy for stroke prevention, which is associated with a risk of bleeding, and pharmacologic, surgical, endovascular (e.g., ablation), or combined treatments to control heart rhythm or heart rate. In addition, ECG may detect other abnormalities (either true- or false-positive results) that can lead to further testing and treatments that have the potential for harm.
Few data are available on the current prevalence of screening for AF with ECG or other modalities or the frequency with which pulse palpation or heart auscultation are performed in the United States.
Additional Tools and Resources
The Centers for Disease Control and Prevention provides information on the prevention of heart disease at https://www.cdc.gov/heartdisease/prevention.htm and useful information about AF at https://www.cdc.gov/heartdisease/atrial_fibrillation.htm.
The Million Hearts initiative provides information on improving cardiovascular health and preventing heart attack and stroke at https://millionhearts.hhs.gov/index.html.
Other Related USPSTF Recommendations
The USPSTF has made recommendations on many factors related to the prevention of cardiovascular disease and stroke, including screening for high blood pressure,18 use of statins,19 counseling on smoking cessation,20 and counseling to promote a healthy diet and physical activity.21
When final, this recommendation will replace the 2018 USPSTF recommendation statement on screening for AF with ECG. In 2018, the USPSTF concluded that the evidence was insufficient to assess the balance of benefits and harms of using ECG to screen for AF.22 For the current draft recommendation statement, the USPSTF expanded its review to include other screening tests in addition to ECG. The USPSTF again concludes that the evidence is insufficient to assess the balance of benefits and harms of screening for AF in asymptomatic adults.
Scope of Review
To update its 2018 recommendation statement, the USPSTF commissioned a systematic review10 of the evidence on the benefits and harms of screening for AF in older adults, the accuracy of screening tests, the effectiveness of screening tests to detect previously undiagnosed AF compared with usual care, and the benefits and harms of anticoagulant therapy for the treatment of screen-detected AF in older adults.
Detection of Previously Undiagnosed AF
The USPSTF found four randomized clinical trials comparing different one-time screening approaches for the detection of AF to usual care or no screening.23-29 The mean age in these trials was 74 to 76 years. Of these trials, only one, the Screening for Atrial Fibrillation in the Elderly (SAFE) trial, found a statistically significant increased detection rate of AF (0.6% absolute increase) when comparing no intervention to ECG; however, there was no difference between provider reminders for pulse palpation (considered usual care by the USPSTF) and screening with ECG in the detection of new cases of AF.23 Fidelity to the intervention was low to modest in all four studies, ranging from 11% to 69%.10
Two of these trials reported on measures of accuracy of screening tests. The SAFE trial reported that the sensitivity of ECG interpreted by a general practitioner compared with 12-lead ECG interpreted by a cardiologist ranged from 0.80 to 0.85, and specificity ranged from 0.86 to 0.92.23,25 The Detecting and Diagnosing Atrial Fibrillation trial did not report sensitivity or specificity.29 However, in that trial, if one considers the screening test positive if any of its components (pulse palpation, oscillometric blood pressure measurement with automated AF detection, and single-lead ECG with automated AF detection) were positive, the positive predictive value was 6% and the negative predictive value was 100%.10
The USPSTF found two trials that used intermittent or continuous screening approaches. The mean age in these trials was 73 and 72 years. The Assessment of Remote Heart Rhythm Sampling using the AliveCor heart monitor to screen for Atrial Fibrillation (REHEARSE-AF) (n=1,001) trial randomized participants to twice-weekly screening with a single-lead, handheld ECG for 30 seconds or to no screening for 12 months.30 The mHealth Screening to Prevent Strokes (mSToPS) (n=2,659) trial randomized participants to screening with two 14-day episodes of continuous ambulatory ECG monitoring with a patch 3 months apart or to delayed screening.31 Both trials reported statistically significant absolute risk differences of about 3 percentage points in detection rates of AF for screening vs. no screening or delayed screening. Neither study reported measures of screening accuracy. Two separate studies of different single-lead ECG devices with automated AF detection algorithms used as a one-time screening test reported sensitivities of 0.88 and 0.99 and specificities of 1.0 and 0.7632,33 when compared with a single 12-lead ECG interpreted by a cardiologist.
Another trial of screening for AF with two 2-week episodes of continuous ambulatory ECG patch monitoring 3 months apart plus twice daily use of an automated home blood pressure monitor with an AF detection algorithm compared with usual care was recently published34 and is currently being reviewed by the USPSTF.
It is important to note that intermittent or continuous screening approaches may be more likely to detect short episodes of nonpersistent AF. Relatedly, the mSToPS trial reported that the longest individual episode of AF detected during its total of 28 days of monitoring was less than 5 minutes in 7.2% of participants, 5 minutes to 6 hours in 55%, 6 to 24 hours in 25%, and more than 24 hours in 13%.31 It is uncertain to what degree short episodes of subclinical AF increase stroke risk, and the duration of subclinical AF that warrants anticoagulation is unclear.8,9
Benefits of Early Detection and Treatment
The USPSTF found one trial, REHEARSE-AF, that reported on health outcomes. It found no difference in all-cause mortality or in a composite outcome of stroke, transient ischemic attack, and systemic embolism between the screening and no screening groups, although it was not designed or powered for health outcomes.30
The USPSTF found no trials that reported on the benefits of anticoagulant therapy in screen-detected populations. Several trials reported on the benefits of anticoagulant therapy for clinical AF. In a pooled analysis of five trials, warfarin treatment over an average of 1.5 years was associated with reductions in all-cause mortality (pooled relative risk [RR], 0.68 [95% CI, 0.50 to 0.93]; 2,415 participants), ischemic stroke (pooled RR, 0.32 [95% CI, 0.20 to 0.51];), and moderately to severely disabling stroke (pooled RR, 0.38 [95% CI, 0.19 to 0.78];) compared with the control group.10 A network meta-analysis of 21 studies found that all anticoagulant treatments (warfarin or direct oral anticoagulants) reduced the risk of outcomes such as stroke, systemic embolism, and all-cause mortality compared with placebo or control groups.35
Trials of anticoagulant treatment enrolled participants with clinical, usually long-standing, persistent AF; none focused on participants who were detected by screening.10 As discussed above, the extent to which short episodes of subclinical (i.e., asymptomatic or device detected) AF increase stroke risk is uncertain, and the duration or burden of AF that warrants anticoagulation is unclear.8,9 Thus, the applicability of treatment benefits to screen-detected populations, particularly those with short-duration or low-burden AF, is uncertain.
Harms of Screening and Treatment
Two randomized clinical trials reported on the harms of screening for AF. In the SAFE study, anxiety levels were not significantly different between participants randomized to ECG screening vs. pulse palpation reminders. Participants who had a positive screening result had higher mean anxiety scores compared with those who had a negative result, although most did not have clinically meaningful levels of anxiety symptoms.23 The mSToPS trial reported incidentally detected, potentially actionable arrhythmias other than AF in 70 participants (2.6% of participants), although the balance of benefits or harms of these findings is unknown.31 Another potential harm of screening is misinterpretation of ECG, leading to false-positive results and possibly unnecessary treatment.
The USPSTF reviewed several trials, systematic reviews, and an observational study that reported on harms associated with anticoagulant therapy. Anticoagulant therapy was associated with an increased risk of bleeding, including major bleeding, extracranial bleeding, intracranial bleeding, and minor bleeding events, although the increased risk was not statistically significant for all outcomes.10 Similar to the body of evidence on the benefits of anticoagulant treatment, the studies reporting on harms were focused on persons with clinical, usually long-standing, persistent AF; none focused on screen-detected populations.10 However, the harms of anticoagulant therapy in a screen-detected population would likely be similar; thus, the USPSTF assesses that this evidence is applicable to screen-detected AF.
- Randomized trials enrolling asymptomatic persons that directly compare screening to usual care and that assess both health outcomes and harms are needed to understand the balance of benefits and harms of screening for AF. It is important that screening trials enroll sufficient participants of both sexes and diverse racial/ethnic groups to enable assessment of whether the detection of AF or the benefits or harms of screening vary in different population groups.
- More research is needed on how to best optimize the accuracy of screening tests or strategies for AF.
- Understanding the stroke risk associated with subclinical AF, how that risk varies with duration or burden of AF, and the potential benefit of anticoagulation therapy among persons with subclinical AF is an important research need.
The American Heart Association and the American Stroke Association state that active screening for AF in the primary care setting among persons older than age 65 years using pulse assessment followed by ECG, as indicated, can be useful.36
The American Academy of Family Physicians supports the 2018 U.S. Preventive Services Task Force recommendation on screening for AF with ECG.37
Himmelreich JC, Karregat EP, Lucassen WA, et al. Diagnostic accuracy of a smartphone-operated, single-lead electrocardiography device for detection of rhythm and conduction abnormalities in primary care. Ann Fam Med. 2019;17(5):403-411.
Kearley K, Selwood M, Van den Bruel A, et al. Triage tests for identifying atrial fibrillation in primary care: a diagnostic accuracy study comparing single-lead ECG and modified BP monitors. BMJ Open. 2014;4(5):e004565.
Gladstone DJ, Wachter R, Schmalstieg-Bahr K, et al. Screening for atrial fibrillation in the older population: a randomized clinical trial. JAMA Cardiol. 2021:e210038.
Tereshchenko LG, Henrikson CA, Cigarroa J, et al. Comparative effectiveness of interventions for stroke prevention in atrial fibrillation: a network meta-analysis. J Am Heart Assoc. 2016;5(5):e003206.
Meschia JF, Bushnell C, Boden-Albala B, et al. Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(12):3754-3832.
American Academy of Family Physicians. Atrial Fibrillation: Screening With Electrocardiography. https://www.aafp.org/family-physician/patient-care/clinical-recommendations/all-clinical-recommendations/atril-fib.html. Accessed March 15, 2021.
Go AS, Hylek EM, Phillips KA, et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. JAMA. 2001;285(18):2370-2375.
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U.S. Preventive Services Task Force. Procedure Manual. https://uspreventiveservicestaskforce.org/uspstf/about-uspstf/methods-and-processes/procedure-manual. Accessed March 19, 2021.
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 of Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2021;42(5):373-498.
Noseworthy PA, Kaufman ES, Chen LY, et al. Subclinical and device-detected atrial fibrillation: pondering the knowledge gap. A Scientific Statement from the American Heart Association. Circulation. 2019;140:e944-e963.
Benjamin EJ, Go AS, Desvigne-Nickens P, et al. Research priorities in atrial fibrillation screening, a report from a National Heart, Lung, and Blood Institute virtual workshop. Circulation. 2021;143:372-388.
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January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm. 2019;16(8):e66-e93.
Lip GY, Banerjee A, Boriani G, et al. Antithrombotic therapy for atrial fibrillation: CHEST guideline and expert panel report. Chest. 2018;154(5):1121-1201.
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U.S. Preventive Services Task Force. Behavioral and pharmacotherapy interventions for tobacco smoking cessation in adults, including pregnant women: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2015;163(8):622-634.
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|Benefits of Early Detection and Intervention and Treatment||
|Harms of Early Detection and Intervention and Treatment||
|USPSTF Assessment||Evidence is lacking, and the balance of benefits and harms of screening for AF in asymptomatic adults cannot be determined.|