Draft Recommendation Statement
Atrial Fibrillation: Screening With Electrocardiography
This opportunity for public comment expired on January 22, 2018 at 8:00 PM EST
Note: This is a Draft Recommendation Statement. This draft is distributed solely for the purpose of receiving public input. It has not been disseminated otherwise by the USPSTF. The final Recommendation Statement will be developed after careful consideration of the feedback received and will include both the Research Plan and Evidence Review as a basis.
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.
Draft: Recommendation Summary
|Adults age 65 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 with electrocardiography (ECG).
Read the plain-language consumer summary of the draft Recommendation Statement.
The U.S. Preventive Services Task Force (USPSTF) makes recommendations about the effectiveness of specific preventive care services for patients without obvious related signs or symptoms.
It bases its recommendations on the evidence of both the benefits and harms of the service, and an assessment of the balance. The USPSTF does not consider the costs of providing a service in this assessment.
The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decisionmaking to the specific patient or situation. Similarly, the USPSTF notes that policy and coverage decisions involve considerations in addition to the evidence of clinical benefits and harms.
Atrial fibrillation is the most common type of cardiac arrhythmia (i.e., irregular heartbeat), and its prevalence increases with age, affecting about 10% of adults age 85 years and older. Atrial fibrillation is a major risk factor for ischemic stroke, increasing stroke risk by as much as five-fold. Approximately 20% of patients who have a stroke associated with atrial fibrillation are first diagnosed with atrial fibrillation at the time of stroke or shortly thereafter.
The USPSTF found inadequate evidence to assess whether screening with ECG identifies older adults with previously undiagnosed atrial fibrillation more effectively than usual care.
Benefits of Early Detection and Intervention and Treatment
The USPSTF found no trials directly assessing the benefit of screening for atrial fibrillation with ECG on clinical outcomes. The USPSTF found adequate evidence that anticoagulant treatment reduces the incidence of stroke in patients with symptomatic atrial fibrillation. Given the inadequate evidence on screening with ECG for the detection of atrial fibrillation in asymptomatic adults, there is inadequate evidence to determine the magnitude of benefit of screening followed by treatment.
Harms of Early Detection and Intervention and Treatment
The USPSTF found adequate evidence that screening for atrial fibrillation with ECG is associated with small to moderate harms, such as misdiagnosis, additional testing and invasive procedures, and overtreatment.
The USPSTF concludes that there is insufficient evidence to determine the balance of benefits and harms of screening for atrial fibrillation with ECG in asymptomatic adults. Evidence is lacking and the balance of benefits and harms cannot be determined.
Draft: Clinical Considerations
Patient Population Under Consideration
This recommendation applies to older adults (age 65 years and older) without symptoms of atrial fibrillation.
Suggestions for Practice Regarding the I Statement
Potential Preventable Burden
Atrial fibrillation is the most common type of cardiac arrhythmia, affecting more than 2.7 million Americans.1 Atrial fibrillation is strongly associated with older age (e.g., prevalence increases from 0.2% among adults age <55 years to 10% among those age ≥85 years) and obesity, both of which are increasing in the United States.2 Other risk factors include high blood pressure, diabetes, heart failure, prior cardiothoracic surgery, current smoking, prior stroke, sleep apnea, alcohol and drug use, and hyperthyroidism.
Without anticoagulant treatment, patients with atrial fibrillation have an approximately five-fold increased risk of stroke, and strokes associated with atrial fibrillation tend to be more severe than strokes attributed to other causes.3 Approximately one-third of patients with atrial fibrillation who have a stroke die within the year, and up to 30% of survivors have some type of permanent disability.4 Atrial fibrillation does not always cause noticeable symptoms, and some persons may not be aware that they have it. For about 20% of patients who have a stroke associated with atrial fibrillation, it is the first sign that they have the condition.5 If persons with undiagnosed atrial fibrillation could be detected earlier and start preventive therapy earlier, some of these strokes might be avoided.
The performance of ECG itself is not associated with significant harm, although abnormal results may cause anxiety. Misinterpretation of ECG results may lead to overdiagnosis and unnecessary treatment. Treatment of atrial fibrillation includes anticoagulant therapy to prevent stroke, which is associated with bleeding risk, and pharmacologic, surgical, endovascular (e.g., ablation), or combined treatments to control heart rhythm or rate. In addition, ECG may detect other abnormalities (either true- or false-positive results) that can lead to invasive confirmatory testing and treatments that have the potential for serious harm. For example, angiography and revascularization are associated with risks, including bleeding, contrast-induced nephropathy, and allergic reactions to the contrast agent.
Few data are available on the current prevalence of screening for atrial fibrillation with ECG or simpler methods, such as pulse palpation or heart auscultation, in the United States.
There are several possible approaches to screening for atrial fibrillation. The most simple approach is pulse palpation, which is often part of a routine examination, and has relatively good sensitivity (point estimate, 0.87 to 1.00) but lower specificity (point estimate, 0.77 to 0.84).6 Heart auscultation can also detect an irregular heartbeat. Both tests may be considered part of usual care, but there are few data on whether they are consistently practiced. ECG, either measured with 12 leads, fewer than 12 leads, or a handheld single lead, has good sensitivity and specificity but requires training and experience for interpretation. One systematic review reported a 93% sensitivity and 97% specificity for 12-lead ECG; individual studies in the review reported sensitivity ranging from 68% to 100% and specificity ranging from 76% to 100%.6 In addition, several medical devices (e.g., automatic blood pressure cuffs and pulse oximeters) are being designed to detect an irregular heartbeat, and a growing number of consumer devices (e.g., wearable monitors and smart phones) have the capability to assess heart rhythm.7
Treatment and Interventions
Treatment of atrial fibrillation has two components—managing the arrhythmia and preventing stroke. In general, these treatment goals are independent of each other, because even restoring sinus rhythm does not necessarily reduce stroke risk enough to change management of anticoagulant therapy, given the potential for subsequent recurrence of atrial fibrillation. The 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. Some evidence suggests that selected patients may be able to reverse atrial fibrillation through lifestyle changes that address the underlying causes of atrial fibrillation.8 For patients with atrial fibrillation and high stroke risk (defined as a CHA2DS2-VASc score ≥2), this risk can be reduced through anticoagulant medication—either vitamin K antagonists (e.g., warfarin) or, more recently, nonvitamin K antagonist oral anticoagulants. A device that blocks off the atrial appendage to prevent blood clots has also been recently approved by the U.S. Food and Drug Administration as a nonpharmacologic alternative to anticoagulant medications for selected patients.
Additional Approaches to Prevention
The Million Hearts® campaign provides tools and protocols to support the prevention of ischemic heart disease, one of the major causes of atrial fibrillation.9 The Centers for Disease Control and Prevention also provides information about programs and resources for the prevention of heart disease.10
The USPSTF has made recommendations on many factors related to stroke prevention, including screening for high blood pressure,11 use of statins,12 counseling on smoking cessation,13 and counseling to promote healthful diet and physical activity.14 In addition, the USPSTF recommends low-dose aspirin use for persons at increased risk of cardiovascular disease.15
Draft: Other Considerations
Research Needs and Gaps
The connection between atrial fibrillation and stroke is well established, as is the existence of undiagnosed atrial fibrillation, especially among older adults. Randomized trials enrolling asymptomatic persons that directly compare screening with usual care and that assess both health outcomes and harms are needed to understand the balance of benefits and harms of screening for atrial fibrillation. Other research needs include understanding the relative benefits of opportunistic vs. systematic screening and how to best optimize the accuracy of ECG interpretation. Although the evidence review for this recommendation statement focused on screening with ECG, the effectiveness of pulse palpation and newer technologies capable of assessing pulse and rhythm as potential screening strategies should be evaluated.
There are several ongoing trials that may help to fill these evidence gaps. The STROKESTOP study (ClinicalTrials.gov identifier NCT01593553) randomized 28,768 adults ages 75 to 76 years in Sweden to be invited or not invited for screening, first with 12-lead ECG and then intermittently with a handheld single-lead ECG device over 2 weeks. The primary outcome is stroke incidence, and results are anticipated in 2019. The SCREEN-AF study (ClinicalTrials.gov identifier NCT02392754) plans to randomize more than 800 participants to a 2-week ambulatory ECG patch monitor or usual care. The primary outcome is new diagnosis of ECG-confirmed atrial fibrillation or flutter, but clinical events are included as secondary outcomes. The expected completion date is July 2018. The IDEAL-MD study (ClinicalTrials.gov identifier NCT02270151) randomized 16,000 adults older than age 65 years to screening with a single-lead ECG device or usual care. The primary outcome is new diagnosis of atrial fibrillation over 1 year; secondary outcomes will include major cardiovascular events and all-cause mortality. Last, the Detecting and Diagnosing Atrial Fibrillation (D2AF) study (Netherlands Trial Register no. 4914) is a cluster randomized trial that compares different approaches to case-finding among adults age 65 years and older. The primary outcome is the difference in detection rate of new atrial fibrillation cases over 1 year compared with usual care; however, it does not include clinical outcomes.
Burden of Disease
Atrial fibrillation affects more than 2.7 million Americans.1 The prevalence of atrial fibrillation increases with age, from less than 0.2% among adults younger than age 55 years to 10% among those older than age 85 years.2 Although the age-adjusted hospitalization rate for atrial fibrillation for patients older than age 65 years has stabilized since 2006, it has steadily increased for younger adults.16 A meta-analysis of 19 studies found that about 1% of the adult population may have undiagnosed atrial fibrillation, although the prevalence varies among different populations.5 Atrial fibrillation may progress over time, causing worsening symptoms and exacerbating heart failure. Atrial fibrillation is also an important cause of stroke, accounting for 14% to 24% of all cases of ischemic stroke.5 Persons with persistent and permanent atrial fibrillation have the highest stroke risk, but even paroxysmal (intermittent) atrial fibrillation, which accounts for 25% of all cases, increases the incidence of stroke.17
Scope of Review
The USPSTF commissioned a systematic review5 to evaluate the evidence on the benefits and harms of screening for atrial fibrillation with ECG, the effectiveness of screening with ECG for detecting previously undiagnosed atrial fibrillation compared with usual care, and the benefits and harms of anticoagulant or antiplatelet therapy for the treatment of screen-detected atrial fibrillation in older adults.
Detection of Previously Undiagnosed Atrial Fibrillation
Two fair-quality randomized, controlled trials in the United Kingdom assessed screening for atrial fibrillation with ECG. The first study randomized 3001 patients (mean age, 75 years) to opportunistic screening (physicians and nurses were encouraged to record the patient’s pulse and follow up an irregular pulse with 12-lead ECG) or systematic screening (invitation to attend nurse-led screening with pulse palpation and single-lead ECG).18 The study found no statistically significant difference between systematic and opportunistic screening (risk difference, 0.0033 [95% confidence interval (CI), -0.002 to 0.009]), although there were few cases of atrial fibrillation and the CI was wide.
The second study (Screening for Atrial Fibrillation in the Elderly [SAFE]) randomized patients at 50 primary care practices (N=14,802; mean age, 75 years) to usual care, opportunistic screening (physicians and nurses were encouraged to check the patient’s pulse and follow up an irregular pulse with 12-lead ECG), or systematic screening (invitation to attend nurse-led screening with pulse palpation and 12-lead ECG).19-23 The SAFE study found that both opportunistic and systematic screening increased detection of atrial fibrillation by 0.6% over baseline prevalence, but found no difference between opportunistic and systematic screening in the detection of new cases.19 The study reported that 29% of cases detected with opportunistic screening and 43% of cases detected with systematic screening had a CHADS2 score of 2 or greater, and thus would be eligible for anticoagulant therapy to prevent stroke.20 The SAFE study also reported subanalyses by age and sex. Age had no effect on detection rates; however, while both opportunistic and systematic screening significantly increased the odds of detecting atrial fibrillation among men (odds ratio, 2.33 [95% CI, 1.30 to 4.15] and odds ratio, 2.68 [95% CI, 1.52 to 4.73], respectively), neither screening approach improved detection rates among women.5
The SAFE study also assessed the accuracy of diagnosis by comparing ECG interpretation at the primary care clinics with that of three cardiologists assigned to read the same results. The primary care clinics, which had general practitioners reading 12-lead ECG results, had relatively low sensitivity (79.8% [95% CI, 70.5 to 87.2]) and specificity (91.6% [95% CI, 90.1 to 93.1]); sinus rhythm was misinterpreted as atrial fibrillation in 114 of 1,355 cases.22 Adding a computer algorithm improved the sensitivity of primary care clinic readings from 80% to 92% but did not affect specificity.21
Effectiveness of Early Detection and Treatment
The USPSTF found no studies that reported clinical outcomes from screening programs for atrial fibrillation using ECG. Four cohort studies suggest that persons with asymptomatic atrial fibrillation have an increased stroke risk similar to that of persons with symptomatic atrial fibrillation, although the risk of selection bias, ascertainment bias (for determining symptom status), and confounding were high.5 The USPSTF did not find any trials of treatment of asymptomatic, screen-detected participants. Most treatment trial participants had established persistent nonvalvular atrial fibrillation, although the prevalence of symptoms was generally not reported. Six randomized, controlled trials and seven systematic reviews including more than 100,000 patients with atrial fibrillation concluded that anticoagulant therapy reduces all-cause mortality by about one-third and ischemic stroke by about two-thirds over 2 years among patients with atrial fibrillation and high stroke risk (usually determined by CHADS2 or CHA2DS2-VASc score).5
Potential Harms of Screening and Treatment
Only one included study directly examined the harms of screening. The SAFE study reported anxiety, but only for the intervention group, thus precluding comparative assessment.22 One potential source of harms from screening with ECG is additional testing that leads to harms (e.g., complications from unnecessary stress testing or angiography performed on the basis of false-positive results). Based on large, population-based registries that include symptomatic persons, angiography is associated with a serious harm rate of 1.7%, including arrhythmia (0.40%), death (0.10%), stroke (0.07%), and myocardial infarction (0.05%).24 Revascularization increases the risk of periprocedural myocardial infarction (1.7%), coronary artery dissection (1.3%), bleeding events within 72 hours (1.3%), vascular complications (0.4%), renal failure (0.4%), stroke (0.1%), and death on day of procedure (<0.01%).25 Anticoagulant therapy for stroke prevention also increases the risk of serious bleeding.
Estimate of Magnitude of Net Benefit
Most older adults with previously undiagnosed atrial fibrillation have a stroke risk above the threshold for anticoagulant therapy and would be eligible for treatment. Anticoagulant therapy is effective for preventing stroke in symptomatic patients with atrial fibrillation. However, the USPSTF found inadequate evidence to determine whether screening with ECG and subsequent treatment in asymptomatic adults is more effective than opportunistic screening or usual care. At the same time, the harms of diagnostic followup and treatment prompted by abnormal ECG results are well established. Given these uncertainties, it is not possible to determine the net benefit of screening.
Draft: Recommendations of Others
In 2014, the American Heart Association and the American Stroke Association stated that active screening for atrial fibrillation in the primary care setting among patients older than age 65 years using pulse assessment followed by ECG, as indicated, can be useful.26
1. Centers for Disease Control and Prevention. Atrial Fibrillation Fact Sheet. https://www.cdc.gov/dhdsp/data_statistics/fact_sheets/fs_atrial_fibrillation.htm. 2017. Accessed November 30, 2017.
2. 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):2370-5.
3. Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation as an independent risk factor for stroke: the Framingham study. Stroke. 1991;22(8):983-8.
4. Menke J, Lüthje L, Kastrup A, Larsen J. Thromboembolism in atrial fibrillation. Am J Cardiol. 2010;105(4):502-10.
5. Jonas DE, Kahwati LC, Yun JY, Cook Middleton J, Coker-Schwimmer M, Asher GN. Screening for Atrial Fibrillation With Electrocardiography: An Evidence Review for the U.S. Preventive Services Task Force. Evidence Synthesis No. 164. AHRQ Publication No. 17-05236-EF-1. Rockville, MD: Agency for Healthcare Research and Quality; 2017.
6. Welton NJ, McAleenan A, Thom HH, et al. Screening strategies for atrial fibrillation: a systematic review and cost-effectiveness analysis. Health Technol Assess. 2017;21(29):1-236.
7. Taggar JS, Coleman T, Lewis S, Heneghan C, Jones M. Accuracy of methods for detecting an irregular pulse and suspected atrial fibrillation: a systematic review and meta-analysis. Eur J Prev Cardiol. 2016;23(12):1330-8.
8. Pathak RK, Elliott A, Middeldorp ME, et al. Impact of cardiorespiratory fitness on arrhythmia recurrence in obese individuals with atrial fibrillation: the CARDIO-FIT study. J Am Coll Cardiol. 2015;66(9):985-96.
9. Million Hearts®. Tools & Protocols. https://millionhearts.hhs.gov/tools-protocols/index.html. 2017. Accessed November 30, 2017.
10. Centers for Disease Control and Prevention. Educational Materials for Professionals. https://www.cdc.gov/heartdisease/materials_for_professionals.htm. 2017. Accessed November 30, 2017.
11. U.S. Preventive Services Task Force. Screening for high blood pressure in adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2015;163(10):778-86.
12. US Preventive Services Task Force. Statin use for the primary prevention of cardiovascular disease in adults: US Preventive Services Task Force recommendation statement. JAMA. 2016;316(19):1997-2007.
13. 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):622-34.
14. U.S. Preventive Services Task Force. Behavioral counseling to promote a healthful diet and physical activity for cardiovascular disease prevention in adults with cardiovascular risk factors: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;161(8):587-93.
15. U.S. Preventive Services Task Force. Aspirin use for the primary prevention of cardiovascular disease and colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2016;164(12):836-45.
16. Kato E, Ngo-Metzger Q, Fingar KR, McDermott K, Elixhauser A. Inpatient Stays Involving Atrial Fibrillation and Ischemic Stroke, 1998–2014. HCUP Statistical Brief. Rockville, MD: Agency for Healthcare Research and Quality; 2017. In press.
17. Link MS, Giugliano RP, Ruff CT, et al; ENGAGE AF-TIMI 48 Investigators. Stroke and mortality risk in patients with various patterns of atrial fibrillation: results from the ENGAGE AF-TIMI 48 Trial (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48). Circ Arrhythm Electrophysiol. 2017;10(1). pii: e004267
18. Morgan S, Mant D. Randomised trial of two approaches to screening for atrial fibrillation in UK general practice. Br J Gen Pract. 2002;52(478):373-4, 377-80.
19. Fitzmaurice DA, Hobbs FD, Jowett S, et al. Screening versus routine practice in detection of atrial fibrillation in patients aged 65 or over: cluster randomised controlled trial. BMJ. 2007;335(7616):383.
20. Fitzmaurice DA, McCahon D, Baker J, et al. Is screening for AF worthwhile? Stroke risk in a screened population from the SAFE study. Fam Pract. 2014;31(3):298-302.
21. Mant J, Fitzmaurice DA, Hobbs FD, et al. Accuracy of diagnosing atrial fibrillation on electrocardiogram by primary care practitioners and interpretative diagnostic software: analysis of data from screening for atrial fibrillation in the elderly (SAFE) trial. BMJ. 2007;335(7616):380.
22. Hobbs FD, Fitzmaurice DA, Mant J, et al. A randomised controlled trial and cost-effectiveness study of systematic screening (targeted and total population screening) versus routine practice for the detection of atrial fibrillation in people aged 65 and over. The SAFE study. Health Technol Assess. 2005;9(40):iii-iv, ix-x, 1-74.
23. Swancutt D, Hobbs R, Fitzmaurice D, et al. A randomised controlled trial and cost effectiveness study of systematic screening (targeted and total population screening) versus routine practice for the detection of atrial fibrillation in the over 65s: (SAFE) [ISRCTN19633732]. BMC Cardiovasc Disord. 2004;4:12.
24. Noto TJ Jr, Johnson LW, Krone R, et al. Cardiac catheterization 1990: a report of the Registry of the Society for Cardiac Angiography and Interventions (SCA&I). Cathet Cardiovasc Diagn. 1991;24(2):75-83.
25. Schulman-Marcus J, Feldman DN, Rao SV, et al. Characteristics of patients undergoing cardiac catheterization before noncardiac surgery: a report from the National Cardiovascular Data Registry CathPCI Registry. JAMA Intern Med. 2016;176(5):611-8.
26. Meschia JF, Bushnell C, Boden-Albala B, et al; American Heart Association Stroke Council; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; Council on Functional Genomics and Translational Biology; Council on Hypertension. Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(12):3754-832.
Internet Citation: Draft Recommendation Statement: Atrial Fibrillation: Screening With Electrocardiography. U.S. Preventive Services Task Force. December 2017.