Atrial Fibrillation with Electrocardiography: Screening -- Older Adults


General

Grade: I The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined. Read the clinical considerations section of USPSTF Recommendation Statement. If the service is offered, patients should understand the uncertainty about the balance of benefits and harms.

Specific Recommendations

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).   See the Clinical Considerations section for suggestions for practice regarding the I statement.

Frequency of Service

No information available.

Risk Factor Information

Atrial fibrillation is strongly associated with older age and obesity. 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.


Clinical

Patient Population Under Consideration

This recommendation applies to older adults (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 individuals in the United States.1 Atrial fibrillation is strongly associated with older age (eg, prevalence increases from 0.2% among adults <55 years to 10% among those ≥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.

Electrocardiography, the intervention considered for this recommendation, records the electrical activity of the heart using electrodes (or leads) placed on the skin. It can be measured with 12 leads, fewer than 12 leads, or a single handheld lead. 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%.3 In addition, several medical devices (eg, automatic blood pressure cuffs and pulse oximeters) are being designed to detect an irregular heartbeat, and an increasing number of consumer devices (eg, wearable monitors and smartphones) have the capability to assess heart rhythm.4

Pulse palpation and heart auscultation can also detect atrial fibrillation. In the systematic review discussed above, pulse palpation was reported to have relatively good sensitivity (point estimate, 0.87-1.00) but lower specificity than ECG (point estimate, 0.77-0.84) for detecting atrial fibrillation.3 However, to address this lower specificity, confirmatory ECG can be readily performed in practice in response to an irregular pulse.

Without treatment with anticoagulant therapy, patients with atrial fibrillation have an approximately 5-fold increased risk of stroke, and strokes associated with atrial fibrillation tend to be more severe than strokes attributed to other causes.5 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.6 Atrial fibrillation does not always cause noticeable symptoms, and some persons may not be aware that they have it. For approximately 20% of patients who have a stroke associated with atrial fibrillation, stroke is the first sign that they have the condition.7 If persons with undiagnosed atrial fibrillation could be detected earlier and start preventive therapy earlier, some of these strokes might be avoided.

Potential Harms

The performance of ECG itself is not associated with significant harm, although abnormal results may cause anxiety. Misinterpretation of ECG results may lead to misdiagnosis and unnecessary treatment. Treatment of atrial fibrillation includes anticoagulant therapy for stroke prevention, which is associated with a risk of bleeding, and pharmacologic, surgical, endovascular (eg, 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 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.

Current Practice

Few data are available on the current prevalence of screening for atrial fibrillation with ECG or the frequency with which pulse palpation or heart auscultation are performed in the United States.

Treatment and Interventions

Treatment of atrial fibrillation has 2 components—managing 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 how anticoagulant therapy is managed, given the potential for subsequent recurrence of atrial fibrillation. 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 Stroke risk for persons with nonvalvular atrial fibrillation can be estimated with tools such as CHADS2 (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism [doubled]) (developed by Gage and colleagues, Washington University School of Medicine) or its updated version, CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, stroke/transient ischemic attack/thromboembolism [doubled], vascular disease [prior myocardial infarction, peripheral artery disease, or aortic plaque], age 65-74 years, sex category [female]) (Lip and colleagues, University of Birmingham Centre for Cardiovascular Sciences). These tools use somewhat different combinations of patient characteristics and presence or absence of comorbid conditions, as outlined above, to estimate annual risk of stroke and guide decisions about anticoagulation therapy. For patients with atrial fibrillation and high stroke risk (defined as a CHA2DS2-VASc score of ≥2), this risk can be reduced with anticoagulant therapy—either vitamin K antagonists (eg, warfarin) or, more recently, non–vitamin K antagonist oral anticoagulants. A device that blocks off the atrial appendage to prevent blood clots has also been recently approved by the US Food and Drug Administration as a nonpharmacologic alternative to anticoagulant therapy for selected patients.

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

Useful Resources

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 use of low-dose aspirin for certain persons at increased risk of cardiovascular disease.15


Rationale

Importance

Atrial fibrillation is the most common type of cardiac arrhythmia (ie, irregular heartbeat), and its prevalence increases with age, affecting about 3% of men and 2% of women aged 65 to 69 years and about 10% of adults 85 years and older. Atrial fibrillation is a major risk factor for ischemic stroke, increasing risk of stroke by as much as 5-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.

Detection

The USPSTF found inadequate evidence to assess whether screening with ECG identifies adults 65 years and older with previously undiagnosed atrial fibrillation more effectively than usual care.

Benefits of Early Detection and Intervention and Treatment

The USPSTF found inadequate evidence directly assessing the benefit of screening for atrial fibrillation with ECG on clinical outcomes. The USPSTF found adequate evidence that treatment with anticoagulant therapy 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 with ECG 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 also found adequate evidence that treatment of atrial fibrillation with anticoagulant therapy is associated with a small to moderate harm of increased risk of major bleeding.

USPSTF Assessment

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.


Others

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 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 newer technologies capable of assessing pulse and heart rhythm as potential screening strategies should be evaluated. In addition, as ECG and other technologies (eg, AliveCOR Kardia system [AliveCor Inc], discussed in the context of the REHEARSE-AF trial below) are used to record heart activity for longer periods and thus are able to detect shorter episodes of arrhythmia, understanding the stroke risk associated with brief episodes of subclinical atrial fibrillation, and the potential benefit of anticoagulation therapy if risk is significant, is another important research need. Several ongoing trials may help to fill these evidence gaps. The STROKESTOP study (ClinicalTrials.gov identifier NCT01593553This link goes offsite. Click to read the external link disclaimer) randomized 28,768 Swedish adults aged 75 to 76 years to be invited or not invited for screening, first with 12-lead ECG and then intermittently with a single handheld lead over 2 weeks. The primary outcome is stroke incidence. The SCREEN-AF study (ClinicalTrials.gov identifier NCT02392754This link goes offsite. Click to read the external link disclaimer) randomized 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 IDEAL-MD study (ClinicalTrials.gov identifier NCT02270151This link goes offsite. Click to read the external link disclaimer) randomized 16,000 adults older than 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 include major cardiovascular events and all-cause mortality. Last, the Detecting and Diagnosing Atrial Fibrillation (D2AF) study (Netherlands Trial Register No. NTR4914This link goes offsite. Click to read the external link disclaimer) is a cluster randomized trial that compares different approaches to case-finding among adults 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, the study does not include clinical outcomes.   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 persons older than 65 years using pulse assessment followed by ECG, as indicated, can be useful.27 The European Society of Cardiology recommends opportunistic screening by pulse palpation or an ECG rhythm strip in persons older than 65 years and recommends considering systematic screening to detect atrial fibrillation in persons older than 75 years or those at high risk of stroke.28


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