Mass Screening for Atrial Fibrillation: The Hype, The Methods, and The Application
2019; Elsevier BV; Volume: 132; Issue: 6 Linguagem: Inglês
10.1016/j.amjmed.2018.12.027
ISSN1555-7162
Autores Tópico(s)Cardiac Arrhythmias and Treatments
ResumoRecently, Apple launched new heart-related features for their Apple Watch, including an app cleared by the US Food and Drug Administration that notifies wearers if atrial fibrillation has occurred. Apple admits, however, that the watch cannot detect all episodes; inconclusive results are possible; and it is not intended for people with known atrial fibrillation.1Baig EC Apple watch's ECG app could help save lives.USA Today. December 7, 2018; : 3BGoogle Scholar Notably, this comes shortly after the US Preventive Services Task Force published an advisory stating: “the current evidence is insufficient to assess the balance of benefits and harms of screening for atrial fibrillation with electrocardiograms (ECG).”2Jonas DE Kahwati LC Yun JDY Middleton JC Coker-Schwimmer M Asher GN Screening for atrial fibrillation with electrocardiography: evidence report and systematic review for the US Preventive Services Task Force.JAMA. 2018; 320: 485-498Crossref PubMed Scopus (71) Google Scholar So, what is the public to do about atrial fibrillation screening? The answer depends on whether screening is needed (Table 1).Table 1Reasons and Methods to Screen for AF in Patients with No AF HistoryReasons• None proven in the general population.• Symptom assessment.• Presumptive in patients with increased likelihood of AF: • Prevent abnormal atrial remodeling, symptoms, hospitalizations, morbidity or mortality via postdetection prophylactic therapy.Methods• Pulse palpation.• Electrocardiograms.• Ambulatory monitoring, including Holter monitors, auto-triggered loop recorders, handheld, or other self-applied, smart device app, etc.• Implanted or inserted devices, including pacemakers and defibrillators that can be interrogated to assess detected arrhythmias, and newer miniaturized cardiac monitors that are insertable and optimal for long-term continuous monitoring in patients where maximal identification of AF and AF burden is desired.AF = atrial fibrillation. Open table in a new tab AF = atrial fibrillation. In patients with unexplained but atrial fibrillation-compatible symptoms, determining if atrial fibrillation is causative is important for diagnosis and therapy. However, this is quite different than mass screening of the public to seek atrial fibrillation when no hint of it exists, risk from atrial fibrillation is low, and treatment implications are uncertain. In contrast, understanding the relationship among atrial fibrillation, thromboembolism, and utility of prophylactic anticoagulation3Lin HJ Wolf PA Kelly-Hayes M et al Stroke severity in atrial fibrillation. The Framingham Study.Stroke. 1996; 27: 1760-1764Crossref PubMed Scopus (1103) Google Scholar has prompted pre-event identification efforts using progressively advanced monitoring technologies in subjects with demographic, genetic, or laboratory risk markers4Reiffel JA Optimum risk assessment for stroke in atrial fibrillation: should we hold the status quo or consider magnitude synergism and left atrial appendage anatomy.Arrhythm Electrophysiol Rev. 2017; 6: 161-166Crossref PubMed Scopus (8) Google Scholar that identify an increased likelihood of having atrial fibrillation with thromboembolic risk and in whom cost-effective oral anticoagulation reduces thromboembolic events. Monitoring such patients seems appropriate because atrial fibrillation is often asymptomatic and unrecognized until thromboembolism; symptomatic and asymptomatic atrial fibrillation patients have similar adverse outcome rates5Thind M DaJuanicia NH Badri M et al.Embolic and other adverse outcomes in symptomatic versus asymptomatic patients with atrial fibrillation (from the ORBIT-AF Registry).Am J Cardiol. 2018; 122: 1677-1683Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar; device-detected atrial fibrillation has been linked to increased stroke and death risk6Reiffel J Verma A Halperin JL et al.Rationale and design of REVEAL AF: a prospective study of previously undiagnosed atrial fibrillation as documented by an insertable cardiac monitor in high-risk patients.Am Heart J. 2014; 167: 22-27Crossref PubMed Scopus (28) Google Scholar; and, most of these atrial fibrillation-linked demographics are also high-risk markers for thromboembolism in patients with atrial fibrillation. This contrasts with the uncertain and likely low cost-benefit of mass population screening, especially with smartwatches most often worn by younger individuals,7Rowland C Apple now says its smartwatch tech to detect atrial fibrillation is not for those with atrial fibrillation.The Washington Post. December 6, 2018; (Available at:)https://www.washingtonpost.com/business/economy/apple-now-says-its-smartwatch-app-to-detect-atrial-fibrillation-is-not-for-those-with-atrial-fibrillation/2018/12/06/cb5c46bc-f978-11e8-8c9a-860ce2a8148f_story.html?utm_term=.94ae53fa7a50Date accessed: January 17, 2019Google Scholar such as millennials in whom high-risk markers for thromboembolism in atrial fibrillation are infrequent. If one believes detecting atrial fibrillation in subjects with high-risk markers for thromboembolism is an important public health goal and its treatment is warranted, then we should monitor such individuals. Detection may occur fortuitously during an electrocardiogram (ECG), but it is more likely via systematic ECG screening at specific time points, such as yearly medical visits; opportunistic ECG screening, such as during vaccinations or pharmacy visits; scheduled ambulatory ECG monitoring with varying devices for variable durations; semi-continuous monitoring with a smartwatch; or continuous monitoring with an inserted or implanted device. With external monitoring in differing populations using various devices but not smartwatches, atrial fibrillation detection has been 0.2%–5.3%.8Mairesse GH Moran P Van Gelder IC et al.Screening for atrial fibrillation: a EHRA consensus document, endorsed by HRS, APHRS, and SOLAECE.Europace. 2017; 19: 1589-1623Crossref PubMed Scopus (185) Google Scholar, 9Fitzmaurice 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: 383-388Crossref PubMed Scopus (294) Google Scholar, 10Halcox JPJ Wareham K Cardew A et al Assessment of Remote Heart Rhythm Sampling Using the AliveCor Heart Monitor to Screen for Atrial Fibrillation The REHEARSE-AF Study.Circulation. 2017; 136: 1-11Crossref Scopus (324) Google Scholar, 11Omboni S Verberk WJ Opportunistic screening of atrial fibrillation by automatic blood pressure measurement in the community.BMJ Open. 2016; 6e010745Crossref PubMed Scopus (21) Google Scholar, 12Sandhu RK Dolovich L Deif B et al High prevalence of modifiable stroke risk factors identified in a pharmacy-based screening programme.Open Heart. 2016; 3e000515Crossref PubMed Scopus (37) Google Scholar, 13Chan NY Choy CC Chan CK Siu CW Effectiveness of a nongovernmental organization-led large-scale community atrial fibrillation screening program using the smartphone electrocardiogram: an observational cohort study.Heart Rhythm. 2018; 15: 1306-1311Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar, 14Steinhubl SR Waalen J Edwards AM et al Effect of a Home-Based Wearable Continuous ECG Monitoring Patch on Detection of Undiagnosed Atrial Fibrillation: The mSToPS Randomized Clinical Trial.JAMA. 2018; 320: 146-155Crossref PubMed Scopus (251) Google Scholar Importantly, detection of atrial fibrillation increases with longer durations of monitoring.8Mairesse GH Moran P Van Gelder IC et al.Screening for atrial fibrillation: a EHRA consensus document, endorsed by HRS, APHRS, and SOLAECE.Europace. 2017; 19: 1589-1623Crossref PubMed Scopus (185) Google Scholar, 9Fitzmaurice 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: 383-388Crossref PubMed Scopus (294) Google Scholar, 10Halcox JPJ Wareham K Cardew A et al Assessment of Remote Heart Rhythm Sampling Using the AliveCor Heart Monitor to Screen for Atrial Fibrillation The REHEARSE-AF Study.Circulation. 2017; 136: 1-11Crossref Scopus (324) Google Scholar, 11Omboni S Verberk WJ Opportunistic screening of atrial fibrillation by automatic blood pressure measurement in the community.BMJ Open. 2016; 6e010745Crossref PubMed Scopus (21) Google Scholar, 12Sandhu RK Dolovich L Deif B et al High prevalence of modifiable stroke risk factors identified in a pharmacy-based screening programme.Open Heart. 2016; 3e000515Crossref PubMed Scopus (37) Google Scholar, 13Chan NY Choy CC Chan CK Siu CW Effectiveness of a nongovernmental organization-led large-scale community atrial fibrillation screening program using the smartphone electrocardiogram: an observational cohort study.Heart Rhythm. 2018; 15: 1306-1311Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar, 14Steinhubl SR Waalen J Edwards AM et al Effect of a Home-Based Wearable Continuous ECG Monitoring Patch on Detection of Undiagnosed Atrial Fibrillation: The mSToPS Randomized Clinical Trial.JAMA. 2018; 320: 146-155Crossref PubMed Scopus (251) Google Scholar, 15Reiffel JA When silence isn't golden: the case of “silent” atrial fibrillation.J Innovations Cardiac Rhythm Manage. 2017; 8: 2886-2893Crossref Google Scholar One could assume that general population screening with smartwatches (which are not worn continuously) would also yield single digits per year incidences. Of note, not all atrial fibrillation detected by devices is new. In an AFinder Program in Hong Kong,13Chan NY Choy CC Chan CK Siu CW Effectiveness of a nongovernmental organization-led large-scale community atrial fibrillation screening program using the smartphone electrocardiogram: an observational cohort study.Heart Rhythm. 2018; 15: 1306-1311Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar 2.3% had atrial fibrillation detected, but detection of new cases of atrial fibrillation occurred in only 0.69%. That is contrasted with significantly higher newly detected cases of atrial fibrillation that ranged from 20% to 40% during 12-30 months of follow-up in single-arm trials using continuously recording implanted or inserted cardiac monitors in patients without known atrial fibrillation but with demographic or laboratory markers common to atrial fibrillation.15Reiffel JA When silence isn't golden: the case of “silent” atrial fibrillation.J Innovations Cardiac Rhythm Manage. 2017; 8: 2886-2893Crossref Google Scholar Recognizing that atrial fibrillation is often intermittent or transient, one can understand why intermittent monitoring will miss many atrial fibrillation events that can be identified with inserted monitors (Figure 1). Inherently, given the greater likelihood of atrial fibrillation in patients with demographic or laboratory markers prevalent in the population with atrial fibrillation,4Reiffel JA Optimum risk assessment for stroke in atrial fibrillation: should we hold the status quo or consider magnitude synergism and left atrial appendage anatomy.Arrhythm Electrophysiol Rev. 2017; 6: 161-166Crossref PubMed Scopus (8) Google Scholar continuous monitoring should detect atrial fibrillation more frequently in such subjects than in the general public and with a higher incidence than is possible with any external monitors, including smartwatches. To this end, various intermittent monitoring approaches were modeled against continuous monitoring using the implanted or inserted cardiac monitors in REVEAL AF.16Reiffel JA Verma A Kowey P et al.A comparison of atrial fibrillation monitoring strategies in patients at high risk for atrial fibrillation and stroke: results from the REVEAL AF study.J Am Coll Cardiol. 2018; 71https://doi.org/10.1016/S0735-1097(18)30815-5Crossref Google Scholar The monitor recordings allowed multiple noncontinuous models to be extracted from its continuous data set. Atrial fibrillation lasting ≥6 minutes on the monitors was 27.1% at 12 months. This exceeded estimated rates from all simulated intermittent monitoring approaches: 0.8% with 24 hours of monitoring to 6.2% with 30 days of continuous monitoring one time. For repeated monitoring strategies, 12-month atrial fibrillation detection ranged from 3.5%, with quarterly 24-hour Holter monitoring to 10.6% with quarterly 7-day monitoring. Modeling of the smartwatch was not performed, but it would certainly be lower than continuous implanted or inserted monitor recordings, although it should be greater in this demographically enriched population than in the general public. Finally, while the app provides an opportunity to screen for atrial fibrillation, for most of the general population in whom atrial fibrillation is detected, its value and the need for treatment is uncertain. In contrast, in subjects with demographic or laboratory characteristics with a higher likelihood of having atrial fibrillation4Reiffel JA Optimum risk assessment for stroke in atrial fibrillation: should we hold the status quo or consider magnitude synergism and left atrial appendage anatomy.Arrhythm Electrophysiol Rev. 2017; 6: 161-166Crossref PubMed Scopus (8) Google Scholar and an indication for therapy if atrial fibrillation is found,15Reiffel JA When silence isn't golden: the case of “silent” atrial fibrillation.J Innovations Cardiac Rhythm Manage. 2017; 8: 2886-2893Crossref Google Scholar optimal screening is now via easily inserted, low-risk subcutaneous monitors. Moreover, only continuous monitoring allows for determination of atrial fibrillation burden, which was recently recognized an important parameter17Chen LY Chung MK Allen LA et al.Atrial Fibrillation Burden: moving beyond atrial fibrillation as a binary entity: a scientific statement from the American Heart Association.Circulation. 2018; 137: e623-e644Crossref PubMed Scopus (204) Google Scholar because thromboembolic risk appears related not simply to atrial fibrillation as present or absent but also to the quantity of fibrillation present. Because atrial fibrillation may be symptom free, have poor symptom-arrhythmia correlation, or be intermittent, its timely diagnosis often requires active detection efforts. The smartwatch can overcome some of these limitations but not as well as an insertable cardiac monitor. No doubt the smartwatch capable of detecting atrial fibrillation will become a marketplace hit, like all new technological advances, but to what importance other than to the stock market and device sales? Detection is only needed in subjects where it matters.
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