Stepwise screening of atrial fibrillation in a 75-year-old population: implications for stroke prevention

Probing oral anticoagulation in patients with atrial high rate episodes: Rationale and design of the Non-vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH-AFNET 6) trial

Oral anticoagulation prevents ischemic strokes in patients with atrial fibrillation (AF). Early detection of AF and subsequent initiation of oral anticoagulation help to prevent strokes in AF patients. Implanted cardiac pacemakers and defibrillators allow seamless detection of atrial high rate episodes (AHRE), but the best antithrombotic therapy in patients with AHRE is not known.

Rationale

Stroke risk is higher in pacemaker patients with AHRE than in those without, but the available data also show that stroke risk in patients with AHRE is lower than in patients with AF. Furthermore, only a minority of patients with AHRE will develop AF, many strokes occur without a temporal relation to AHRE, and AHRE can reflect other arrhythmias than AF or artifacts. An adequately powered controlled trial of oral anticoagulation in patients with AHRE is needed.

Design

The Non–vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH–AFNET 6 ) trial tests whether oral anticoagulation with edoxaban is superior to prevent the primary efficacy outcome of stroke or cardiovascular death compared with aspirin or no antithrombotic therapy based on evidence-based indications. The primary safety outcome will be major bleeding. NOAH–AFNET 6 will randomize 3,400 patients with AHRE, but without documented AF, aged ≥65 years with at least 1 other stroke risk factor, to oral anticoagulation therapy (edoxaban) or no anticoagulation. All patients will be followed until the end of this investigator-driven, prospective, parallel-group, randomized, event-driven, double-blind, multicenter phase IIIb trial. Patients will be censored when they develop AF and offered open-label anticoagulation. The sponsor is the Atrial Fibrillation NETwork (AFNET). The trial is supported by the DZHK (German Centre for Cardiovascular Research), the BMBF (German Ministry of Education and Research), and Daiichi Sankyo Europe.

Conclusion

NOAH–AFNET 6 will provide robust information on the effect of oral anticoagulation in patients with atrial high rate episodes detected by implanted devices.

Screening for Atrial Fibrillation

Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed in September 2015 to promote discussion and research about AF screening as a strategy to reduce stroke and death and to provide advocacy for implementation of country-specific AF screening programs. During 2016, 60 expert members of AF-SCREEN, including physicians, nurses, allied health professionals, health economists, and patient advocates, were invited to prepare sections of a draft document. In August 2016, 51 members met in Rome to discuss the draft document and consider the key points arising from it using a Delphi process. These key points emphasize that screen-detected AF found at a single timepoint or by intermittent ECG recordings over 2 weeks is not a benign condition and, with additional stroke factors, carries sufficient risk of stroke to justify consideration of anticoagulation. With regard to the methods of mass screening, handheld ECG devices have the advantage of providing a verifiable ECG trace that guidelines require for AF diagnosis and would therefore be preferred as screening tools. Certain patient groups, such as those with recent embolic stroke of uncertain source (ESUS), require more intensive monitoring for AF. Settings for screening include various venues in both the community and the clinic, but they must be linked to a pathway for appropriate diagnosis and management for screening to be effective. It is recognized that health resources vary widely between countries and health systems, so the setting for AF screening should be both country- and health system-specific. Based on current knowledge, this white paper provides a strong case for AF screening now while recognizing that large randomized outcomes studies would be helpful to strengthen the evidence base.

Screening strategies for atrial fibrillation: a systematic review and cost-effectiveness analysis

Background

Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of thromboembolic events. Anticoagulation therapy to prevent AF-related stroke has been shown to be cost-effective. A national screening programme for AF may prevent AF-related events, but would involve a substantial investment of NHS resources.

Objectives

To conduct a systematic review of the diagnostic test accuracy (DTA) of screening tests for AF, update a systematic review of comparative studies evaluating screening strategies for AF, develop an economic model to compare the cost-effectiveness of different screening strategies and review observational studies of AF screening to provide inputs to the model.

Design

Systematic review, meta-analysis and cost-effectiveness analysis.

Setting

Primary care.

Participants

Adults.

Intervention

Screening strategies, defined by screening test, age at initial and final screens, screening interval and format of screening {systematic opportunistic screening [individuals offered screening if they consult with their general practitioner (GP)] or systematic population screening (when all eligible individuals are invited to screening)}.

Main outcome measures

Sensitivity, specificity and diagnostic odds ratios; the odds ratio of detecting new AF cases compared with no screening; and the mean incremental net benefit compared with no screening.

Review methods

Two reviewers screened the search results, extracted data and assessed the risk of bias. A DTA meta-analysis was perfomed, and a decision tree and Markov model was used to evaluate the cost-effectiveness of the screening strategies.

Results

Diagnostic test accuracy depended on the screening test and how it was interpreted. In general, the screening tests identified in our review had high sensitivity (> 0.9). Systematic population and systematic opportunistic screening strategies were found to be similarly effective, with an estimated 170 individuals needed to be screened to detect one additional AF case compared with no screening. Systematic opportunistic screening was more likely to be cost-effective than systematic population screening, as long as the uptake of opportunistic screening observed in randomised controlled trials translates to practice. Modified blood pressure monitors, photoplethysmography or nurse pulse palpation were more likely to be cost-effective than other screening tests. A screening strategy with an initial screening age of 65 years and repeated screens every 5 years until age 80 years was likely to be cost-effective, provided that compliance with treatment does not decline with increasing age.

Conclusions

A national screening programme for AF is likely to represent a cost-effective use of resources. Systematic opportunistic screening is more likely to be cost-effective than systematic population screening. Nurse pulse palpation or modified blood pressure monitors would be appropriate screening tests, with confirmation by diagnostic 12-lead electrocardiography interpreted by a trained GP, with referral to a specialist in the case of an unclear diagnosis. Implementation strategies to operationalise uptake of systematic opportunistic screening in primary care should accompany any screening recommendations.

Limitations

Many inputs for the economic model relied on a single trial [the Screening for Atrial Fibrillation in the Elderly (SAFE) study] and DTA results were based on a few studies at high risk of bias/of low applicability.

Future work

Comparative studies measuring long-term outcomes of screening strategies and DTA studies for new, emerging technologies and to replicate the results for photoplethysmography and GP interpretation of 12-lead electrocardiography in a screening population.

Study registration

This study is registered as PROSPERO CRD42014013739.

Funding

The National Institute for Health Research Health Technology Assessment programme.

Impact of atrial fibrillation detected by extended monitoring-A population-based cohort study

BACKGROUND

The clinical relevance of extended monitoring of AF in the general population is unclear. The study evaluated the detection of AF using transtelephonic electrocardiography and the clinical relevance of additional AF findings, especially with regard to stroke risk and mortality.

METHODS

The data of 1678 volunteers participating in the tele-ECG-subproject of the Study of Health in Pomerania was evaluated. Occurrence of AF as revealed by tele-ECG and conventional ECG was evaluated. Associations with mortality, history of stroke, and other clinical parameters were analyzed.

RESULTS

AF was detected in 21 subjects (1.3%) by conventional ECG (ECG-AF) and in 43 (2.6%) by tele-ECG. All individuals with AF revealed by conventional ECG were also diagnosed to have AF by tele-ECG; 22 were diagnosed by tele-ECG only (Tele-AF). During follow-up (median: 6.3 years) 42/1635, 1/22, and 5/21 participants died in the no-AF-, tele-AF-, and ECG-AF groups (p < .001). Whereas, in comparison to the no-AF group, the risk of death was higher in the ECG-AF group (HR 9.4; 3.7-23.8; p < .001), there was no significant increase in mortality in the tele-AF group (HR 1.9; 0.26-14.0; p = .52). Prevalence of stroke history was higher in the ECG-AF group (19%; 5.5-42%) than with the no-AF (1.9%; 1.3-2.7%; p = .001) and the tele-AF groups (0%; 0-15%; p = .05).

CONCLUSIONS

Tele-ECG identifies significantly more AF cases in a population-based setting compared to conventional ECG. The impact of AF diagnosed only by extended monitoring differs from conventionally diagnosed AF. Additional studies are warranted, since this might have an impact on clinical management.

First Diagnosis of Atrial Fibrillation at the Time of Stroke

BACKGROUND

Atrial fibrillation (AF) is a major cause of ischemic stroke. Individuals with undiagnosed AF lack the stroke protection afforded by oral anticoagulants. We obtained a contemporary estimate of the percentage of AF patients newly diagnosed at the time of stroke.

METHODS

We identified patients admitted to the Massachusetts General Hospital (MGH) from January 1, 2010 to December 31, 2013 with acute ischemic stroke and either previously or newly diagnosed AF using hospital stroke registry data and stroke and AF ICD-9 code searches of hospital databases. Reviewers categorized AF as previously known or newly diagnosed, and collected comorbidity and outcome data. To confirm AF as newly diagnosed, we searched patients' pre-event electronic medical records (EMRs) for AF terms.

RESULTS

AF was considered newly diagnosed in 156/856 patients (18%; 95% CI 16-21). In 136/156 cases, AF was diagnosed using 12-lead EKG, telemetry, or rhythm strips. New AF strokes had a median NIH stroke scale of 12; 60% had mRankin ≥3 at discharge, including 15% deaths. Pre-stroke CHA2DS2-VASc score was ≥2 in 89%. About half (76/156) had prior records in the MGH EMR. Evidence of pre-stroke AF, often peri-procedural, was found in 8/76, but the AF diagnosis was not carried forward.

CONCLUSIONS

In this contemporary cohort, nearly one in 5 AF-related strokes occurred without a pre-stroke AF diagnosis. AF was readily diagnosed using standard rhythm monitoring. The vast majority of patients with newly diagnosed AF were at high enough pre-stroke risk to merit anticoagulation. In conclusion, our findings support screening for AF before stroke. Patients with past transient AF may merit more intensive screening.

High prevalence of modifiable stroke risk factors identified in a pharmacy-based screening programme

Background

Population-based screening for atrial fibrillation (AF) is a promising public health strategy to prevent stroke. However, none of the published reports have evaluated comprehensive screening for additional stroke risk factors such as hypertension and diabetes in a pharmacy setting.

Methods

The Program for the Identification of ‘Actionable’ Atrial Fibrillation in the Pharmacy Setting (PIAAF-Pharmacy) screened individuals aged ≥65 years, attending community pharmacies in Canada, who were not receiving oral anticoagulation (OAC). Participants were screened for AF using a hand-held ECG device, had blood pressure (BP) measured, and diabetes risk estimated using the Canadian Diabetes Risk Assessment Questionnaire (CANRISK) questionnaire. ‘Actionable’ AF was defined as unrecognised or undertreated AF. A 6-week follow-up visit with the family physician was suggested for participants with ‘actionable’ AF and a scheduled 3-month visit occurred at an AF clinic.

Results

During 6 months, 1145 participants were screened at 30 pharmacies. ‘Actionable’ AF was identified in 2.5% (95% CI 1.7 to 3.6; n=29); of these, 96% were newly diagnosed. Participants with ‘actionable AF’ had a mean age of 77.2±6.8 years, 58.6% were male and 93.1% had a CHA₂DS₂-VASc score ≥2. A BP>140/90 was found in 54.9% (616/1122) of participants and 44.4% (214/492) were found to be at high risk of diabetes. At 3 months, only 17% of participants were started on OAC, 50% had improved BP and 71% had confirmatory diabetes testing.

Conclusions

Integrated stroke screening identifies a high prevalence of individuals who could benefit from stroke prevention therapies but must be coupled with a defined care pathway.

Stroke as the First Manifestation of Atrial Fibrillation

Atrial fibrillation may remain undiagnosed until an ischemic stroke occurs. In this retrospective cohort study we assessed the prevalence of ischemic stroke or transient ischemic attack as the first manifestation of atrial fibrillation in 3,623 patients treated for their first ever stroke or transient ischemic attack during 2003–2012. Two groups were formed: patients with a history of atrial fibrillation and patients with new atrial fibrillation diagnosed during hospitalization for stroke or transient ischemic attack. A control group of 781 patients with intracranial hemorrhage was compiled similarly to explore causality between new atrial fibrillation and stroke. The median age of the patients was 78.3 [13.0] years and 2,009 (55.5%) were women. New atrial fibrillation was diagnosed in 753 (20.8%) patients with stroke or transient ischemic attack, compared to 15 (1.9%) with intracranial hemorrhage. Younger age and no history of coronary artery disease or other vascular diseases, heart failure, or hypertension were the independent predictors of new atrial fibrillation detected concomitantly with an ischemic event. Thus, ischemic stroke was the first clinical manifestation of atrial fibrillation in 37% of younger (<75 years) patients with no history of cardiovascular diseases. In conclusion, atrial fibrillation is too often diagnosed only after an ischemic stroke has occurred, especially in middle-aged healthy individuals. New atrial fibrillation seems to be predominantly the cause of the ischemic stroke and not triggered by the acute cerebrovascular event.

Atrial electrocardiography in obesity and hypertension: Clinical insights from the Polish-Norwegian Study (PONS)

OBJECTIVE

Obesity and hypertension often coexist and represent risk factors for atrial fibrillation. This study hypothesized that their single and joint effects on atrial remodeling would be reflected in the PR interval and P-wave durations on electrocardiogram (ECG).

METHODS

This cross-sectional analysis of a community-based study included 11,308 men and women age 45-64. Atrial indices were obtained from digital standard 12-lead resting ECG. Analyses were adjusted for traditional cardiovascular risk factors.

RESULTS

Both ECG indices displayed a progressive increase across anthropometric indices. Each 5-unit increment in body mass index (BMI) increased P-wave duration by 1.9 ms (95% CI 1.5-2.2) and PR interval by 2.4 ms (95% CI 1.9-3.0), with similar trends for central obesity, even among those without obesity by BMI. Both ECG indices displayed graded increases across levels of blood pressure control, including prehypertension. A joint effect of overweight and hypertension on both ECG indices was detected. P-wave duration or PR interval among people with obesity was not additionally increased by hypertension.

CONCLUSIONS

P-wave indices increase in general and central obesity. Hypertension exerts an incremental effect in people with overweight but not in people with obesity. The study furthered the understanding of atrial remodeling in the setting of major atrial fibrillation risk factors.

Evaluating the benefits of home-based management of atrial fibrillation: current perspectives

Atrial fibrillation (AF) is the most common arrhythmia worldwide, leading to an extensive public health and economic burden. The increasing incidence and prevalence of AF is due to the advancing age of the population, structural heart disease, hypertension, diabetes, and thyroid disease. The majority of costs associated with AF have been attributed to the cost of hospitalization. In order to minimize costs and decrease hospitalizations, counseling on modifiable risk factors contributing to AF has been strongly emphasized. With the release of novel oral anticoagulants bypassing the need for anticoagulant bridging or laboratory monitoring, post-discharge nurse-led home intervention, and novel methods of heart rate monitoring, home-based AF management has reached a new level of ease and sophistication. In this review, we aimed to review modifiable risk factors for AF and various methods of home-based management of AF, along with their benefits.

Geographic and socio-demographic differences in uptake of population-based screening for atrial fibrillation: The STROKESTOP I study

BACKGROUND

The rationale behind screening for atrial fibrillation (AF) is to prevent ischemic stroke. Socio-demographic differences are expected to affect screening uptake. Geographic differences may provide further insights leading to targeted interventions for improved uptake. The objective of this study was to evaluate geographic and socio-demographic differences in uptake of AF screening in the population-based study STROKESTOP I.

METHODS

STROKESTOP was carried out in two Swedish counties with a total population of 2.3 million inhabitants. Half of the residents aged 75-76years were randomized to the screening arm: invitation to clinical examination followed by ambulant ECG recording. Information on each invited person's residential parish (n=157) was used. On parish-level, aggregated data for the participants and non-participants, respectively, were obtained with respect to socioeconomic variables: educational level, disposable income, immigrant and marital status. Geo-maps displaying participation ratios were estimated by hierarchical Bayes methods.

RESULTS

The overall participation rate was similar in men and women but lower in Stockholm, 47.6% (5665/11,903) than in Halland, 61.2% (1495/2443). Participation was clearly associated with the socioeconomic variables. Participation not taking into account socioeconomy varied more markedly across the parishes in the Stockholm county (range: 0.65-1.26) than in the Halland county (0.94-1.27). After adjustment for socioeconomic variables, a geographic variation remained in Stockholm, but not in Halland.

CONCLUSION

Participation in AF screening varied according to socioeconomic conditions. Geographic variation in participation was marked in the Stockholm county, with only one screening clinic. Geo-mapping of participation yielded useful information needed to intervene for improved screening uptake.

A tailored treatment strategy: a modern approach for stroke prevention in patients with atrial fibrillation

The main priority in atrial fibrillation (AF) management is stroke prevention, following which decisions about rate or rhythm control are focused on the patient, being primarily for management of symptoms. Given that AF is commonly associated with various comorbidities, risk factors such as hypertension, heart failure, diabetes mellitus and sleep apnoea should be actively looked for and managed in a holistic approach to AF management. The objective of this review is to provide an overview of modern AF stroke prevention with a focus on tailored treatment strategies. Biomarkers and genetic factors have been proposed to help identify 'high-risk' patients to be targeted for oral anticoagulation, but ultimately their use must be balanced against that of more simple and practical considerations for everyday use. Current guidelines have directed focus on initial identification of 'truly low-risk' patients with AF, that is those patients with a CHA2 DS2 -VASc [congestive heart failure, hypertension, age ≥75 years (two points), diabetes mellitus, stroke (two points), vascular disease, age 65-74 years, sex category] score of 0 (male) or 1 (female), who do not need any antithrombotic therapy. Subsequently, patients with ≥1 stroke risk factors can be offered effective stroke prevention, that is oral anticoagulation. The SAMe-TT2 R2 [sex female, age <60 years, medical history (>2 comorbidities), treatment (interacting drugs), tobacco use (two points), race non-Caucasian (two points)] score can help physicians make informed decisions on those patients likely to do well on warfarin (SAMe-TT2 R2 score 0-2) or those who are likely to have a poor time in therapeutic range (SAMe-TT2 R2 score >2). A clinically focused tailored approach to assessment and stroke prevention in AF with the use of the CHA2 DS2 VASc, HAS-BLED [hypertension, abnormal renal/liver function (one or two points), stroke, bleeding history or predisposition, labile international normalized ratio, elderly (>65 years) drugs/alcohol concomitantly (one or two points)] and SAMeTT2 R2 scores to evaluate stroke risk, bleeding risk and likelihood of successful warfarin therapy, respectively, is discussed.

Prevalence of atrial fibrillation in an urban population in India: the Nagpur pilot study

OBJECTIVES

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice with major public health impact mainly due to the increased risk of stroke. The recent Global Burden of Disease Study reported a lack of prevalence data from India. Our goal was to conduct a pilot study to evaluate the feasibility of assessing AF prevalence and stroke prophylaxis in an urban Indian community.

METHODS

A screening camp was conducted in Nagpur, India, that evaluated adults aged ≥18 years. We collected demographics, recorded blood pressure, height, weight and the 12-lead electrocardiogram (ECG). The presence of diabetes and hypertension was recorded by self-reported history. Patients diagnosed with AF were evaluated further to assess aetiology and management.

RESULTS

Of the total 4077 randomly selected, community-dwelling adults studied, 0.196% (eight patients) were found to have AF. Mean age of the population was 43.9±14.8, and 44.5% were female. The mean age of the patients with AF was 60.5±15.8 years (five females). Rheumatic heart disease was found in five patients with AF. Three patients had history of stroke (37.5%) and one had peripheral arterial thrombosis. Three patients were on warfarin, but without routine international normalised ratio (INR) monitoring. One patient was on aspirin. Five patients were on β-blockers and one on both β-blocker and digoxin.

CONCLUSIONS

The prevalence of AF was low compared with other regions of the world and stroke prophylaxis was underused. A larger study is needed to confirm these findings. This study demonstrates that larger evaluations would be feasible using the community-based techniques employed here.

Atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, and increases in prevalence with increasing age and the number of cardiovascular comorbidities. AF is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations, dyspnoea and dizziness. The condition can also be associated with serious complications, including an increased risk of stroke. Important recent developments in the clinical epidemiology and management of AF have informed our approach to this arrhythmia. This Primer provides a comprehensive overview of AF, including its epidemiology, mechanisms and pathophysiology, diagnosis, screening, prevention and management. Management strategies, including stroke prevention, rate control and rhythm control, are considered. We also address quality of life issues and provide an outlook on future developments and ongoing clinical trials in managing this common arrhythmia.

The Epidemiology of Atrial Fibrillation and Stroke

The burden of stroke is increasing due to aging population and unhealthy lifestyle habits. The considerable rise in atrial fibrillation (AF) is due to greater diffusion of risk factors and screening programs. The link between AF and ischemic stroke is strong. The subtype most commonly associated with AF is cardioembolic stroke, which is particularly severe and shows the highest rates of mortality and permanent disability. A trend toward a higher prevalence of cardioembolic stroke in high-income countries is probably due to the greater diffusion of AF and the control of atherosclerotic of risk factors.

Typical, atypical, and asymptomatic presentations of new-onset atrial fibrillation in the community: Characteristics and prognostic implications

BACKGROUND

The prognostic significance of the clinical presentation of atrial fibrillation (AF) is poorly defined.

OBJECTIVE

The purpose of this study was to determine the frequency, associations, and prognostic impact of different clinical presentations of new-onset AF.

METHODS

One thousand patients with incident AF in Olmsted County, Minnesota, were randomly selected (2000-2010). Patients with AF that was complicated at presentation (heart failure [n = 71], thromboembolism [n = 24]), provoked (n = 346), or unable to determine symptoms (n = 83) were excluded. In the remaining patients, characteristics and prognosis associated with different types of symptoms were examined.

RESULTS

Among 476 patients, 193 had typical (palpitations), 122 had atypical (other non-palpitation symptoms), and 161 had asymptomatic AF presentation. Patients with typical presentation had lower CHA2DS2-VASc scores (mean 2.3 ± 2) compared to atypical and asymptomatic presentation (mean 3.2 ± 1.8 and 3.3 ± 1.9, respectively; P <.001). Fifty-nine cerebrovascular events and 149 deaths (n = 49 cardiovascular) were documented over median 5.6 and 6.0 years, respectively. Atypical and asymptomatic AF conferred higher risks of cerebrovascular events compared to typical AF after adjustment for CHA2DS2-VASc score and age (hazard ratio [HR] 3.51, 95% confidence interval [CI] 1.65-7.48, and HR 2.70, 95% CI 1.29-5.66, respectively), and associations remained statistically significant after further adjustments including comorbidities and warfarin use. Asymptomatic AF was associated with an increased risk of cardiovascular (HR 3.12, 95% CI 1.50-6.45) and all-cause mortality (HR 2.96, 95% CI 1.89-4.64) compared to typical AF after adjustment for CHA2DS2-VASc score and age.

CONCLUSION

The type of clinical presentation may have important implications for the prognosis of new-onset AF in the community.

Atrial cardiopathy: a broadened concept of left atrial thromboembolism beyond atrial fibrillation

Atrial fibrillation (AF) has long been associated with a heightened risk of ischemic stroke and systemic thromboembolism, but recent data require a re-evaluation of our understanding of the nature of this relationship. New findings about the temporal connection between AF and stroke, alongside evidence linking markers of left atrial abnormalities with stroke in the absence of apparent AF, suggest that left atrial thromboembolism may occur even without AF. These observations undermine the hypothesis that the dysrhythmia that defines AF is necessary and sufficient to cause thromboembolism. In this commentary, we instead suggest that the substrate for thromboembolism may often be the anatomic and physiological atrial derangements associated with AF. Therefore, our understanding of cardioembolic stroke may be more complete if we shift our representation of its origin from AF to the concept of atrial cardiopathy.

Simulation of Daily Snapshot Rhythm Monitoring to Identify Atrial Fibrillation in Continuously Monitored Patients with Stroke Risk Factors

Background

New technologies are diffusing into medical practice swiftly. Hand-held devices such as smartphones can record short-duration (e.g., 1-minute) ECGs, but their effectiveness in identifying patients with paroxysmal atrial fibrillation (AF) is unknown.

Methods

We used data from the TRENDS study, which included 370 patients (mean age 71 years, 71% men, CHADS₂ score≥1 point: mean 2.3 points) who had no documentation of atrial tachycardia (AT)/AF or antiarrhythmic or anticoagulant drug use at baseline. All were subsequently newly diagnosed with AT/AF by a cardiac implantable electronic device (CIED) over one year of follow-up. Using a computer simulation approach (5,000 repetitions), we estimated the detection rate for paroxysmal AT/AF via daily snapshot ECG monitoring over various periods, with the probability of detection equal to the percent AT/AF burden on each day.

Results

The estimated AT/AF detection rates with snapshot monitoring periods of 14, 28, 56, 112, and 365 days were 10%, 15%, 21%, 28%, and 50% respectively. The detection rate over 365 days of monitoring was higher in those with CHADS₂ scores ≥2 than in those with CHADS₂ scores of 1 (53% vs. 38%), and was higher in those with AT/AF burden ≥0.044 hours/day compared to those with AT/AF burden <0.044 hours/day (91% vs. 14%; both P<0.05).

Conclusions

Daily snapshot ECG monitoring over 365 days detects half of patients who developed AT/AF as detected by CIED, and shorter intervals of monitoring detected fewer AT/AF patients. The detection rate was associated with individual CHADS₂ score and AT/AF burden.

Trial Registration

ClinicalTrials.gov NCT00279981

Detecting and Diagnosing Atrial Fibrillation (D2AF): study protocol for a cluster randomised controlled trial

BACKGROUND

Atrial fibrillation is a common cause of stroke and other morbidity. Adequate treatment with anticoagulants reduces the risk of stroke by 60 %. Early detection and treatment of atrial fibrillation could prevent strokes. Atrial fibrillation is often asymptomatic and/or paroxysmal. Case-finding with pulse palpation is an effective screening method, but new methods for detecting atrial fibrillation have been developed. To detect paroxysmal atrial fibrillation ambulatory rhythm recording is needed. This study aims to determine the yield of case-finding for atrial fibrillation in primary care patients. In addition, it will determine the diagnostic accuracy of three different case-finding methods.

METHODS/DESIGN

In a multicenter cluster randomised controlled trial, we compare an enhanced protocol for case-finding of atrial fibrillation with usual care. We recruit 96 practices. We include primary care patients aged 65 years or older not diagnosed with atrial fibrillation. Within each practice, a cluster of 200 patients is randomly selected and marked. Practices are evenly randomised to intervention or control group. The allocation is not blinded. When a marked patient visits an intervention practice, the case-finding protocol starts, consisting of: pulse palpation, sphygmomanometer with automated atrial fibrillation detection and handheld single-lead electrocardiogram (ECG). All patients with at least 1 positive test and a random sample of patients with negative tests receive a 12-lead ECG. Patients without atrial fibrillation on the 12-lead ECG, undergo additional continuous Holter and use the handheld single-lead ECG at home for 2 weeks. Control practices provide care as usual. The study runs for 1 year in each cluster. The primary outcomes are the difference in detection rate of new AF between intervention and control practices and the accuracy of three index tests to diagnose AF. We are currently recruiting practices. The 'Detecting and Diagnosing Atrial Fibrillation' (D2AF) study will determine the yield of an intensive case-finding strategy and the diagnostic accuracy of three index tests to diagnose atrial fibrillation in a primary care setting.

TRIAL REGISTRATION

Netherlands Trial Register: NTR4914 , registered on the 25 of November 2014.

Natriuretic peptides for the detection of paroxysmal atrial fibrillation

Background and purpose

Silent atrial fibrillation (AF) and tachycardia (AT) are considered precursors of ischaemic stroke. Therefore, detection of paroxysmal atrial rhythm disorders is highly relevant, but is clinically challenging. We aimed to evaluate the diagnostic value of natriuretic peptide levels in the detection of paroxysmal AT/AF in a pilot study.

Methods

Natriuretic peptide levels were analysed in two independent patient cohorts (162 patients with arterial hypertension or other cardiovascular risk factors and 82 patients with retinal vessel disease). N-terminal-pro-brain natriuretic peptide (NT-proBNP) and BNP were measured before the start of a 7-day Holter monitoring period carefully screened for AT/AF.

Results

244 patients were included; 16 had paroxysmal AT/AF. After excluding patients with a history of AT/AF (n=5), 14 patients had newly diagnosed AT/AF (5.8%) NT-proBNP and BNP levels were higher in patients with paroxysmal AT/AF in both cohorts: (1) 154.4 (IQR 41.7; 303.6) versus 52.8 (30.4; 178.0) pg/mL and 70.0 (31.9; 142.4) versus 43.9 (16.3; 95.2) and (2) 216.9 (201.4; 277.1) versus 90.8 (42.3–141.7) and 96.0 (54.7; 108.2) versus 29.1 (12.0; 58.1). For the detection of AT/AF episodes, NT-proBNP and BNP had an area under the curve in receiver operating characteristic analysis of 0.76 (95% CI, 0.64 to 0.88; p=0.002) and 0.75 (0.61 to 0.89; p=0.004), respectively.

Conclusions

NT-proBNP and BNP levels are elevated in patients with silent AT/AF as compared with sinus rhythm. Thus, screening for undiagnosed paroxysmal AF using natriuretic peptide level initiated Holter monitoring may be a useful strategy in prevention of stroke or systemic embolism.

Outcome of men and women after atrial fibrillation and stroke

OBJECTIVES

Atrial fibrillation (AF) is a well-known risk factor for ischaemic stroke. The aim was to examine long-term outcome of men and women after stroke related to AF.

METHODS

Patients with AF and ischaemic stroke were followed up 1 year and 5 years after stroke. Level of dependence (Barthel Index), disability (modified Rankin Scale), risk factors, mortality and stroke prophylaxis before and after stroke were analysed. All parameters were compared between men and women.

RESULTS

From a cohort of 597 stroke patients during a one-year period, 155 patients (94 women/61 men) with stroke related to AF were included. Women were older than men at stroke onset and more men had a history of smoking and diabetes, but there was no difference in stroke severity. Only 111 patients had been diagnosed with AF before stroke. After 1 year 78 patients (45 women/33 men) and after 5 years 35 patients (21 women/14 men) were followed up. There was no difference in mortality after 5 years with 76% women and 73% men deceased. Half of both genders were independent 1 year after stroke, and after 5 years, approximately a third among women, but half of the men, were independent. Women were less frequently treated with warfarin before stroke (11% vs 28%), but warfarin and NOAC treatment had increased among both women and men at hospital discharge.

CONCLUSIONS

There were no gender differences in long-term mortality after stroke related to AF. Men were significantly more often prescribed anticoagulants before stroke, a finding that indicates the need for further studies.

Prevalence of atrial fibrillation in patients with high CHADS2- and CHA2DS2VASc-scores: anticoagulate or monitor high-risk patients?

Background

In patients with known atrial fibrillation (AF) different scores are utilized to estimate the risk of thromboembolic events and guide oral anticoagulation. Diagnosis of AF strongly depends on the duration of electrocardiogram monitoring. The aim of this study was to use established scores to predict the prevalence of AF.

Methods

The CHADS₂- (Congestive Heart failure, hypertension, Age >75 years, Diabetes, Stroke [doubled]) and CHA₂DS₂VASc-score (Congestive Heart failure, hypertension, Age ≥75 years [doubled], Diabetes, Stroke [doubled], Vascular disease, Age 65–74 years, Sex category [female sex]) was calculated in 150,408 consecutive patients, referred to the University Hospital of Rostock between 2007 and 2012. All factors constituting these scores and a history of AF were prospectively documented with the ICD-10 admission codes.

Results

Mean age of our study population was 67.6 ± 13.6 years with a mean CHADS₂-score of 1.65 ± 0.92 and CHA₂DS₂VASc-score of 3.04 ± 1.42. AF was prevalent in 15.9% of the participants. The prevalence of AF increased significantly with every CHADS₂- and CHA₂DS₂VASc-score point up to 54.2% in CHADS₂-score of 6 and 71.4% in CHA₂DS₂VASc-score of 9 (P < 0.001).

Conclusion

The prevalence of AF increases with increasing CHADS₂- and CHA₂DS₂VASc-score. In intermediate scores intensified monitoring may be recommended. In high scores, thromboembolic complications occurred irrespective of the presence of AF and anticoagulant therapy may be initiated irrespective of documented AF.

Early detection of occult atrial fibrillation and stroke prevention

Atrial fibrillation (AF) is a very common arrhythmia and significantly increases stroke risk. This risk can be mitigated with oral anticoagulation, but AF is often asymptomatic, or occult, preventing timely detection and treatment. Accordingly, occult AF may cause stroke before it is clinically diagnosed. Currently, guidelines for the early detection and treatment of occult AF are limited. This review addresses recent advancements in occult AF detection methods, identification of populations at high risk for occult AF, the treatment of occult AF with oral anticoagulation, as well as ongoing trials that may answer critically important questions regarding occult AF screening.

Insular Cortex Lesions, Cardiac Troponin, and Detection of Previously Unknown Atrial Fibrillation in Acute Ischemic Stroke

Background and Purpose—

Detection rates of paroxysmal atrial fibrillation (AF) after acute ischemic stroke increase with duration of ECG monitoring. To date, it is unknown which patient group may benefit most from intensive monitoring strategies. Therefore, we aimed to identify predictors of previously unknown AF during in-hospital ECG monitoring.

Methods—

All consecutive patients with imaging-confirmed ischemic stroke admitted to our tertiary care hospital from February 2011 to December 2013 were registered prospectively. Patients received continuous bedside ECG monitoring for at least 24 hours. Detection of previously unknown AF during in-hospital ECG monitoring was obtained from medical records. Patients with AF on admission ECG or known history of AF were excluded from analysis.

Results—

Among 1228 patients (median age, 73 years; median National Institutes of Health Stroke Scale, 4; 43.4% women), previously unknown AF was detected in 114 (9.3%) during a median time of continuous ECG monitoring of 3 days (interquartile range, 2–4 days). Duration of monitoring ( P <0.01), older age ( P <0.01), history of hypertension ( P =0.03), insular cortex involvement ( P <0.01), and higher high-sensitivity cardiac troponin T ( P =0.04) on admission were independently associated with subsequent detection of AF in a multiple regression analysis. Addition of high-sensitivity cardiac troponin T, insular cortex stroke, or both to the CHADS2 score (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke [2P]) significantly improved c -statistics from 0.63 to 0.68 ( P =0.01), 0.70 ( P <0.01), and 0.72 ( P <0.001), respectively.

Conclusions—

Insular cortex involvement, higher admission high-sensitivity cardiac troponin T, older age, hypertension, and longer monitoring are associated with new detection of AF during in-hospital ECG monitoring. Patients with higher high-sensitivity cardiac troponin T or insular cortex involvement may be candidates for prolonged ECG monitoring.

Mass Screening for Untreated Atrial Fibrillation: The STROKESTOP Study

BACKGROUND

The aims of the present study were to define the prevalence of untreated atrial fibrillation (AF) in a systematic screening program using intermittent ECG recordings among 75- to 76-year-old individuals and to study the feasibility of initiating protective oral anticoagulant (OAC) treatment.

METHODS AND RESULTS

Half of the 75- to 76-year-old population in 2 Swedish regions were invited to a screening program for AF. Participants without a previous diagnosis of AF underwent intermittent ECG recordings over 2 weeks. If AF was detected, participants were offered OAC. During the 28-month inclusion period, 13 331 inhabitants were invited. Of these, 7173 (53.8%) participated. Of the participants, 218 (3.0%; 95% confidence interval [CI], 2.7-3.5) were found to have previously unknown AF, and of these, AF was found in 37 (0.5% of the screened population) on their first ECG. The use of intermittent ECGs increased new AF detection 4-fold. A previous diagnosis of AF was known in 9.3% (n=666; 95% CI, 8.6-10.0). Total AF prevalence in the screened population was 12.3%. Of participants with known AF, 149 (2.1%; 95% CI, 1.8-2.4) had no OAC treatment. In total, 5.1% (95% CI, 4.6-5.7) of the screened population had untreated AF; screening resulted in initiation of OAC treatment in 3.7% (95% CI, 3.3-4.2) of the screened population. More than 90% of the participants with previously undiagnosed AF accepted initiation of OAC treatment.

CONCLUSIONS

Mass screening for AF in a 75- to 76-year-old population identifies a significant proportion of participants with untreated AF. Initiation of stroke prophylactic treatment was highly successful in individuals with newly diagnosed AF.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01593553.

Feasibility of extended ambulatory electrocardiogram monitoring to identify silent atrial fibrillation in high-risk patients: the Screening Study for Undiagnosed Atrial Fibrillation (STUDY-AF)

BACKGROUND

Identification of silent atrial fibrillation (AF) could prevent stroke and other sequelae.

HYPOTHESIS

Screening for AF using continuous ambulatory electrocardiographic (ECG) monitoring can detect silent AF in asymptomatic in patients with known risk factors.

METHODS

We performed a single-center prospective screening study using a wearable patch-based device that provides up to 2 weeks of continuous ambulatory ECG monitoring (iRhythm Technologies, Inc.). Inclusion criteria were age ≥55 years and ≥2 of the following risk factors: coronary disease, heart failure, hypertension, diabetes, sleep apnea. We excluded patients with prior AF, stroke, transient ischemic attack, implantable pacemaker or defibrillator, or with palpitations or syncope in the prior year.

RESULTS

Out of 75 subjects (all male, age 69 ± 8.0 years; ejection fraction 57% ± 8.7%), AF was detected in 4 subjects (5.3%; AF burden 28% ± 48%). Atrial tachycardia (AT) was present in 67% (≥4 beats), 44% (≥8 beats), and 6.7% (≥60 seconds) of subjects. The combined diagnostic yield of sustained AT/AF was 11%. In subjects without sustained AT/AF, 11 (16%) had ≥30 supraventricular ectopic complexes per hour.

CONCLUSIONS

Outpatient extended ECG screening for asymptomatic AF is feasible, with AF identified in 1 in 20 subjects and sustained AT/AF identified in 1 in 9 subjects, respectively. We also found a high prevalence of asymptomatic AT and frequent supraventricular ectopic complexes, which may be relevant to development of AF or stroke. If confirmed in a larger study, primary screening for AF could have a significant impact on public health.

Significance and Management Strategies for Patients with Asymptomatic Atrial Fibrillation

Atrial fibrillation (AF) is a common and refractory arrhythmia. Prevalence of AF increases with age. Asymptomatic AF is a state of asymptomatic episodes of arrhythmia and its exact prevalence remains unknown. Ablation and therapy with antiarrhythmic agents may predispose to asymptomatic AF. Detection of silent AF is crucial for prevention of ischaemic stroke. Progress in continuous ECG monitoring by Holter ECG, telemetry methods or implantable devices can provide a useful tools for identifying silent AF. Simple screening procedures like pulse examination and ambulatory ECG may be helpful in arrhythmia detection and logically - ischemic stroke prevention.

Characterization of patients with atrial fibrillation not treated with oral anticoagulants

OBJECTIVE

An underuse of oral anticoagulants (OAC) in patients with atrial fibrillation (AF) has been suggested, as only 50% of all patients with AF receive OAC treatment. Whether this is due to contraindications, lack of an indication to treat, or an expression of underuse is sparsely investigated. This study therefore aimed to characterize individuals without OAC treatment in a real-life population of patients with AF.

DESIGN

Retrospective cross-sectional study. The medical records were scrutinized in order to identify the type of AF, risk factors for embolism and bleeding, and other factors of importance for OAC treatment.

SETTING

The municipalities of Skellefteå and Norsjö, northern Sweden.

SUBJECTS

A total of 2274 living residents with at least one verified episode of AF on or before December 31, 2010.

MAIN OUTCOME MEASURES

Prevalence of treatment with OAC and documented reasons to withhold OAC treatment.

RESULTS

Among all 2274 patients with AF, 1187 (52%) were not treated with OAC. Of the untreated patients, 19% had no indication or had declined or had experienced adverse effects other than bleeding on warfarin treatment. The most common reason to withhold OAC was presence of risk factors for bleeding, found in 38% of all untreated patients. Furthermore, a documented reason could be identified to withhold OAC in 75%.

CONCLUSIONS

Among patients with AF without OAC treatment a reason could be identified to withhold OAC in 75%. The underuse of OAC is estimated to be 25%.

Screening for atrial fibrillation in general practice: a national, cross-sectional study of an innovative technology

BACKGROUND

To test the use of three lead monitoring as a screening tool for atrial fibrillation (AF) in general practice. AF is responsible for up to a quarter of all strokes and is often asymptomatic until a stroke occurs.

METHODS

26 randomly selected general practices identified 80 randomly selected patients aged 70 or older from their database and excluded those known to have AF, those with clinical issues or who had not attended for three years. Up to 40 eligible patients/practice were invited to attend for screening. A 2min three-lead ECG was recorded and collected centrally for expert cardiology assessment. Risk factor data was gathered.

OUTCOMES

(i) point prevalence of AF, (ii) proportion of ECG tracings which were adequate for interpretation, (iii) uptake rate by patients and (iv) acceptability of the screening process to patients and staff (reported separately).

RESULTS

Of 1447 current patients, 1003 were eligible for inclusion, 639 (64%) agreed to take part in screening and 566 (56%) completed screening. The point prevalence rate for AF was 10.3%-2.1% new cases (12 of 566 who were screened) and 9.5% existing cases (137 of 1447 eligible patients). Only four of 570 (0.7%) screening visits did not record a usable ECG and 11 (2.6%) three lead ECGs required a clarifying 12 lead ECG.

CONCLUSIONS

Three lead screening for AF is feasible, effective and offers an alternative to pulse taking or 12 lead ECGs. The availability of this technology may facilitate more effective screening, leading to reduced stroke incidence.

Comparison of the Microlife blood pressure monitor with the Omron blood pressure monitor for detecting atrial fibrillation

Screening for atrial fibrillation (AF) by assessing the pulse is recommended in high-risk patients. Some clinical trials demonstrated that the Microlife blood pressure monitor (BPM) with AF detection is more accurate than pulse palpation. This led to a change in practice guidelines in the United Kingdom where AF screening with the Microlife device is recommended instead of pulse palpation. Many BPMs have irregular heart beat detection, but they have not been shown to detect AF reliably. Recently, one study, in a highly select population, suggested that the Omron BPM with irregular heart beat detection has a higher sensitivity for AF than the Microlife BPM. We compared the Microlife and Omron BPMs to electrocardiographic readings for AF detection in general cardiology patients. Inclusion criteria were age≥50 years without a pacemaker or defibrillator. A total of 199 subjects were enrolled, 30 with AF. Each subject had a 12-lead electrocardiography, 1 Omron BPM reading, and 3 Microlife BPM readings as per device instructions. The Omron device had a sensitivity of 30% (95% confidence interval [CI] 15.4% to 49.1%) with the sensitivity for the first Microlife reading of 97% (95% CI 81.4% to 100%) and the Microlife readings using the majority rule (AF positive if at least 2 of 3 individual readings were positive for AF) of 100% (95% CI 85.9% to 100%). Specificity for the Omron device was 97% (95% CI 92.5% to 99.2%) and for the first Microlife reading of 90% (95% CI 83.8% to 94.2%) and for the majority rule Microlife device of 92% (95% CI 86.2% to 95.7%; p<0.0001). The specificity of both devices is acceptable, but only the Microlife BPM has a sensitivity value that is high enough to be used for AF screening in clinical practice.

The atrial fibrillation epidemic is approaching the physician's door: will mobile technology improve detection?

The rising numbers of people with atrial fibrillation (AF) carry a heavy toll on our graying population. Epidemiological data suggest that AF exists in 1 in 10 individuals aged older than 80 years. The risk of embolic stroke increases along with well-known cardiovascular risk factors. Should there be systematic screening for the elderly? Although 1 in 10 is a huge hit rate in screening for any major illness, the initiative for such programs in AF remains in 'research and development'.At present, cardiologists can utilize implantable loop recorders in patients referred for specialist consultation. Novel technologies are also available, including cloud-based, algorithm-assisted, non-invasive monitoring patches, which allow extended observation periods. What about people in the community without a recognized need for cardiologic investigation? Mobile technology has made detection of pulse irregularity possible without medical attention. Smartphone apps enable opportunistic rhythm monitoring, but true arrhythmias need to be medically verified. AF may be the first common disorder to be effectively screened for by mobile technology. In the spirit of proactive campaigns such as 'Know Your Pulse', we should prepare for rapidly increasing reports of various pulse irregularities.

Prediction and personalised treatment of atrial fibrillation-stroke prevention: consolidated position paper of CVD professionals

Atrial fibrillation (AF) is one of the major morbidity and health economic factors in Europe and often associated with several co-morbidities. This paper (1) underlines the importance of highly professional AF management utilising a multi-disciplinary expertise, especially considering the role of AF regarding the stroke risk and prevention, (2) demonstrates the consolidated position of CVD professionals and (3) emphasises those research aspects that could deepen the understanding of the emergence and the treatment of AF and therefore helps to provide a personalised preventive and more effective management of AF. Specialised calls are considered for that within the new European Programme 'Horizon 2020'.

High Prevalence of Atrial Fibrillation Among Patients With Ischemic Stroke

Background and Purpose—

Atrial fibrillation (AF) is a common cause of devastating but potentially preventable stroke. Estimates of the prevalence of AF among patients with stroke vary considerably because of difficulties in detection of intermittent, silent AF. Better recognition of AF in this patient group may help to identify and offer protection to individuals at risk. Our aim was to determine the nationwide prevalence of AF among patients with ischemic stroke, as well as their use of oral anticoagulation.

Methods—

Cross-sectional study of unselected patients in cross-linked nationwide Swedish health registers. All 94 083 patients with a diagnosis of ischemic stroke in the nationwide stroke register Riks-Stroke between 2005 and 2010 were studied. Information about previously diagnosed AF, and comorbidity, was obtained from the nationwide Patient Register and cross-referenced with the national Drug Register containing data on all dispensed pharmacological prescriptions in Sweden.

Results—

Combination of data from Riks-Stroke and from the Patient Register showed that 31 428 (33.4%) patients with ischemic stroke had previously known, or newly diagnosed, AF. Of those, only 16.2% had received warfarin in a pharmacy within 6 months before stroke onset. After hospital discharge, only 35.0% of the survivors received warfarin within the first 3 months after discharge. The likelihood for underlying AF was strongly correlated to the CHA 2 DS 2 -VASC score, which is a point based scheme for assessment of stroke risk in AF but which also predicts likelihood of AF. In this scheme points are given for age, previous stroke or transient ischemic attack, hypertension, heart failure, diabetes, vascular disease and female sex.

Conclusions—

Access to nationwide register data shows that AF is more common among patients with ischemic stroke than those previously reported. Few patients with stroke and AF had anticoagulant treatment before the event, and few got it after the event. CHA 2 DS 2 -VASc could be a useful monitoring tool to intensify efforts to diagnose AF among patients with cryptogenic stroke.

Increased risk of atrial fibrillation among elderly Norwegian men with a history of long-term endurance sport practice

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The prevalence increases with increasing age. In middle-aged men, endurance sport practice is associated with increased risk of AF but there are few studies among elderly people. The aim of this study was to investigate the role of long-term endurance sport practice as a risk factor for AF in elderly men. A cross-sectional study compared 509 men aged 65-90 years who participated in a long-distance cross-country ski race with 1768 men aged 65-87 years from the general population. Long-term endurance sport practice was the main exposure. Self-reported AF and covariates were assessed by questionnaires. Risk differences (RDs) for AF were estimated by using a linear regression model. After multivariable adjustment, a history of endurance sport practice gave an added risk for AF of 6.0 percent points (pp) (95% confidence interval 0.8-11.1). Light and moderate leisure-time physical activity during the last 12 months reduced the risk with 3.7 and 4.3 pp, respectively, but the RDs were not statistically significant. This study suggests that elderly men with a history of long-term endurance sport practice have an increased risk of AF compared with elderly men in the general population.