173 Silent atrial fibrillation in olmsted county: A community-based study

Protocol for a Systematic Review and Individual Participant Data Meta-Analysis of Randomized Trials of Screening for Atrial Fibrillation to Prevent Stroke

INTRODUCTION

 Atrial fibrillation (AF) is a common cause of stroke. Timely diagnosis of AF and treatment with oral anticoagulation (OAC) can prevent up to two-thirds of AF-related strokes. Ambulatory electrocardiographic (ECG) monitoring can identify undiagnosed AF in at-risk individuals, but the impact of population-based ECG screening on stroke is uncertain, as ongoing and published randomized controlled trials (RCTs) have generally been underpowered for stroke.

METHODS AND ANALYSIS

 The AF-SCREEN Collaboration, with support from AFFECT-EU, have begun a systematic review and individual participant data meta-analysis of RCTs evaluating ECG screening for AF. The primary outcome is stroke. Secondary outcomes include AF detection, OAC prescription, hospitalization, mortality, and bleeding.After developing a common data dictionary, anonymized data will be collated from individual trials into a central database. We will assess risk of bias using the Cochrane Collaboration tool, and overall quality of evidence with the Grading of Recommendations Assessment, Development and Evaluation approach.We will pool data using random effects models. Prespecified subgroup and multilevel meta-regression analyses will explore heterogeneity. We will perform prespecified trial sequential meta-analyses of published trials to determine when the optimal information size has been reached, and account for unpublished trials using the SAMURAI approach.

IMPACT AND DISSEMINATION

 Individual participant data meta-analysis will generate adequate power to assess the risks and benefits of AF screening. Meta-regression will permit exploration of the specific patient, screening methodology, and health system factors that influence outcomes.

TRIAL REGISTRATION NUMBER

 PROSPERO CRD42022310308.

Improving Knowledge and Early Detection of Atrial Fibrillation through a Community-Based Opportunistic Screening Program: What's Your Beat?

A community-based opportunistic screening program was implemented to (i) improve atrial fibrillation (AF) awareness and detection and (ii) assess the performance of the Microlife WatchBP Home A for detecting AF when used in community screening. Screening sessions were conducted among people aged ≥ 65 years with no history of AF at public events across Tasmania, Australia. Participants with positive screening results were referred to their general medical practitioner for assessment. The device’s performance was assessed using the positive predictive value. A total of 1704 eligible participants were screened at 79 sessions. Of these people, 50 (2.9%) had a positive screening result. The device correctly identified AF in 22 (46.8%) participants with positive results. Among those with subsequently confirmed AF, 6 (27.3%) had a history of AF but were not aware of the diagnosis, and 16 (72.7%) were identified to have previously undiagnosed AF, with an overall prevalence of 0.9% (95% CI, 0.58 to 1.52). Oral anticoagulation therapy was initiated in 12 (87.5%) eligible participants. The positive predictive value of the device was 46.8% (95% CI, 33.3 to 60.7). Given the relatively low performance of the device, its application in community-based opportunistic screening programs for AF is unlikely to be cost-effective.

C2HEST score predicts clinical outcomes in heart failure with preserved ejection fraction: a secondary analysis of the TOPCAT trial

BACKGROUND

The C2HEST score has been validated for predicting AF in the general population or post-stroke patients. We aimed to assess whether this risk score could predict incident AF and other clinical outcomes in heart failure with preserved ejection fraction (HFpEF) patients.

METHODS

A total of 2202 HFpEF patients without baseline AF in the TOPCAT trial were stratified by baseline C2HEST score. Cox proportional hazard model and competing risk regression model was used to explore the relationship between C2HEST score and outcomes, including incident AF, stroke, all-cause death, cardiovascular death, any hospitalization, and HF hospitalization. The discriminative ability of the C2HEST score for various outcomes was assessed by calculating the area under the curve (AUC).

RESULTS

The incidence rates of incident AF, stroke, all-cause death, cardiovascular death, any hospitalization, and HF hospitalization were 1.79, 0.70, 3.81, 2.42, 15.50, and 3.32 per 100 person-years, respectively. When the C2HEST score was analyzed as a continuous variable, increased C2HEST score was associated with increased risk of incident AF (HR 1.50, 95% CI 1.29-1.75), as well as increased risks of all-cause death, cardiovascular death, any hospitalization, and HF hospitalization. The AUC for the C2HEST score in predicting incident AF (0.694, 95% CI 0.640-0.748) was higher than all-cause death, cardiovascular death, any hospitalization, or HF hospitalization.

CONCLUSIONS

The C2HEST score could predict the risk of incident AF as well as death and hospitalization with moderately good predictive abilities in patients with HFpEF. Its simplicity may allow the possibility of quick risk assessments in busy clinical settings.

Atrial fibrillation and stroke: how much atrial fibrillation is enough to cause a stroke?

PURPOSE OF REVIEW

The association between atrial fibrillation and stroke is firmly established, and anticoagulation reduces stroke risk in patients with atrial fibrillation. However, the role of anticoagulation in very brief durations of atrial fibrillation (subclinical atrial fibrillation) is an area of controversy.

RECENT FINDINGS

Stroke risk increases alongside burden of atrial fibrillation. Ongoing trials will clarify if 24 h or less of atrial fibrillation on extended monitoring necessitates lifelong anticoagulation. Trials examining empiric anticoagulation for individuals with ESUS did not demonstrate benefit over antiplatelet agents. However, hypothesis-generating sub-analyses suggest that certain at-risk groups may benefit. Atrial cardiopathy is associated with subclinical atrial fibrillation and research examining anticoagulation after ESUS in this population is underway.

SUMMARY

Stroke risk increases alongside burden of ectopic atrial activity. However, this risk may in part be because of prothrombotic dysfunction associated with atrial cardiopathy in addition to the arrhythmia itself. The minimal amount of subclinical atrial fibrillation to warrant anticoagulation for stroke prevention, and how this may be modified by the total duration of monitoring, will be clarified by the results of ongoing clinical trials. Currently research will also help identify whether a select group of ESUS patients who have structural and electrophysiological markers of atrial cardiopathy warrant anticoagulation for secondary prevention.

Clinical classification and the subclinical atrial fibrillation challenge: a position paper of the European Cardiac Arrhythmia Society

Symptomatic atrial fibrillation (AF) or clinical AF is associated with impaired quality of life, higher risk of stroke, heart failure, and increased mortality. Current clinical classification of AF is based on the duration of AF episodes and the recurrence over time. Appropriate management strategy should follow guidelines of Scientific Societies. The last decades have been marked by the advances in mechanism comprehension, better management of symptomatic AF, particularly regarding stroke prevention with the use of direct oral anticoagulants and a wider use of AF catheter or surgical ablations. The advent of new tools for detection of asymptomatic AF including continuous monitoring with implanted electronic devices and the use of implantable cardiac monitors and recently wearable devices or garments have identified what is called "subclinical AF" encompassing atrial high-rate episodes (AHREs). New concepts such as "AF burden" have resulted in new management challenges. Oral anticoagulation has proven to reduce substantially stroke risk in patients with symptomatic clinical AF but carries the risk of bleeding. Management of detected asymptomatic atrial arrhythmias and their relation to clinical AF and stroke risk is currently under evaluation. Based on a review of recent literature, the validity of current clinical classification has been reassessed and appropriate updates are proposed. Current evidence supporting the inclusion of subclinical AF within current clinical classification is discussed as well as the need for controlled trials which may provide responses to current therapeutic challenges particularly regarding the subsets of asymptomatic AF patients that might benefit from oral anticoagulation.

Recurrent Stroke With Rivaroxaban Compared With Aspirin According to Predictors of Atrial Fibrillation: Secondary Analysis of the NAVIGATE ESUS Randomized Clinical Trial

Importance

The NAVIGATE ESUS randomized clinical trial found that 15 mg of rivaroxaban per day does not reduce stroke compared with aspirin in patients with embolic stroke of undetermined source (ESUS); however, it substantially reduces stroke risk in patients with atrial fibrillation (AF).

Objective

To analyze whether rivaroxaban is associated with a reduction of recurrent stroke among patients with ESUS who have an increased risk of AF.

Design, Setting, and Participants

Participants were stratified by predictors of AF, including left atrial diameter, frequency of premature atrial contractions, and HAVOC score, a validated scheme using clinical features. Treatment interactions with these predictors were assessed. Participants were enrolled between December 2014 and September 2017, and analysis began March 2018.

Intervention

Rivaroxaban treatment vs aspirin.

Main Outcomes and Measures

Risk of ischemic stroke.

Results

Among 7112 patients with a mean (SD) age of 67 (9.8) years, the mean (SD) HAVOC score was 2.6 (1.8), the mean (SD) left atrial diameter was 3.8 (1.4) cm (n = 4022), and the median (interquartile range) daily frequency of premature atrial contractions was 48 (13-222). Detection of AF during follow-up increased for each tertile of HAVOC score: 2.3% (score, 0-2), 3.0% (score, 3), and 5.8% (score, >3); however, neither tertiles of the HAVOC score nor premature atrial contractions frequency impacted the association of rivaroxaban with recurrent ischemic stroke (P for interaction = .67 and .96, respectively). Atrial fibrillation annual incidence increased for each tertile of left atrial diameter (2.0%, 3.6%, and 5.2%) and for each tertile of premature atrial contractions frequency (1.3%, 2.9%, and 7.0%). Among the predefined subgroup of patients with a left atrial diameter of more than 4.6 cm (9% of overall population), the risk of ischemic stroke was lower among the rivaroxaban group (1.7% per year) compared with the aspirin group (6.5% per year) (hazard ratio, 0.26; 95% CI, 0.07-0.94; P for interaction = .02).

Conclusions and Relevance

The HAVOC score, left atrial diameter, and premature atrial contraction frequency predicted subsequent clinical AF. Rivaroxaban was associated with a reduced risk of recurrent stroke among patients with ESUS and moderate or severe left atrial enlargement; however, this needs to be independently confirmed before influencing clinical practice.

Identification of patients with embolic stroke of undetermined source and low risk of new incident atrial fibrillation: The AF-ESUS score

Background and aims

Only a minority of patients with Embolic Stroke of Undetermined Source (ESUS) receive prolonged cardiac monitoring despite current recommendations. The identification of ESUS patients who have low probability of new diagnosis of atrial fibrillation (AF) could potentially support a strategy of more individualized allocation of available resources and hence, increase their diagnostic yield. We aimed to develop a tool that can identify ESUS patients who have low probability of new incident AF.

Methods

We performed multivariate stepwise regression in a pooled dataset of consecutive ESUS patients from three prospective stroke registries to identify predictors of new incident AF. The coefficient of each independent covariate of the fitted multivariable model was used to generate an integer-based point scoring system.

Results

Among 839 patients (43.1% women, median age 67.0 years) followed-up for a median of 24.3 months (2999 patient-years), 125 (14.9%) had new incident AF. The proposed score assigns 3 points for age ≥ 60 years; 2 points for hypertension; −1 point for left ventricular hypertrophy reported at echocardiography; 2 points for left atrial diameter >40 mm; −3 points for left ventricular ejection fraction <35%; 1 point for the presence of any supraventricular extrasystole recorded during all available 12-lead standard electrocardiograms performed during hospitalization for the ESUS; −2 points for subcortical infarct; −3 points for the presence of non-stenotic carotid plaques. The rate of new incident AF during follow-up was 1.97% among the 42.3% of the cohort who had a score of ≤0, compared to 26.9% in patients with > 0 (relative risk: 13.7, 95%CI: 5.9--31.5). The area under the curve of the score was 84.8% (95%CI: 79.9--86.9%). The sensitivity and negative predictive value of a score of ≤0 for new incident AF during follow-up were 94.9% (95%CI: 89.3--98.1%) and 98.0% (95%CI: 95.8--99.3%), respectively.

Conclusions

The proposed AF-ESUS score has high sensitivity and high negative predictive value to identify ESUS patients who have low probability of new incident AF. Patients with a score of 1 or more may be better candidates for prolonged automated cardiac monitoring.

Clinical trial registration

URL: https://www.clinicaltrials.gov / Unique identifier: NCT02766205.

Management of asymptomatic arrhythmias: a European Heart Rhythm Association (EHRA) consensus document, endorsed by the Heart Failure Association (HFA), Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), Cardiac Arrhythmia Society of Southern Africa (CASSA), and Latin America Heart Rhythm Society (LAHRS)

Asymptomatic arrhythmias are frequently encountered in clinical practice. Although studies specifically dedicated to these asymptomatic arrhythmias are lacking, many arrhythmias still require proper diagnostic and prognostic evaluation and treatment to avoid severe consequences, such as stroke or systemic emboli, heart failure, or sudden cardiac death. The present document reviews the evidence, where available, and attempts to reach a consensus, where evidence is insufficient or conflicting.

Screening to identify unknown atrial fibrillation

Atrial fibrillation (AF) is associated with a significantly increased stroke risk which is highly preventable with appropriate oral anticoagulant therapy (OAC). However, AF may be asymptomatic and unrecognised prior to stroke. We aimed to determine if single time-point screening for AF could identify sufficient numbers with previously undiagnosed AF, to be effective for stroke prevention. This is a systematic review of clinical trials, by searching electronic medical databases, reference lists and grey literature. Studies were included if they evaluated a general ambulant adult population, using electrocardiography or pulse palpation to identify AF. We identified 30 individual studies (n=122,571, mean age 64 years, 54% male) in nine countries. Participants were recruited either from general practitioner and outpatient clinics (12 studies) or population screening/community advertisements (18 studies). Prevalence of AF across all studies was 2.3% (95% CI, 2.2–2.4%), increasing to 4.4% (CI, 4.1–4.6%) in those ≥65 years (16 studies, n= 27,884). Overall incidence of previously unknown AF (14 studies, n=67,772) was 1.0% (CI, 0.89–1.04%), increasing to 1.4% (CI, 1.2–1.6%) in those ≥65 years (8 studies, n= 18,189) in whom screening setting did not influence incidence identified. Of those with previously unknown AF, 67% were at high risk of stroke. Screening can identify 1.4% of the population ≥65 years with previously undiagnosed AF. Many of those identified would be eligible for, and benefit from OAC to prevent stroke. Given this incidence, community AF screening strategies in at risk older age groups could potentially reduce the overall health burden associated with AF.

Feasibility and cost-effectiveness of stroke prevention through community screening for atrial fibrillation using iPhone ECG in pharmacies

Atrial fibrillation (AF) causes a third of all strokes, but often goes undetected before stroke. Identification of unknown AF in the community and subsequent anti-thrombotic treatment could reduce stroke burden. We investigated community screening for unknown AF using an iPhone electrocardiogram (iECG) in pharmacies, and determined the cost-effectiveness of this strategy. Pharmacists performed pulse palpation and iECG recordings, with cardiologist iECG over-reading. General practitioner review/12-lead ECG was facilitated for suspected new AF. An automated AF algorithm was retrospectively applied to collected iECGs. Cost-effectiveness analysis incorporated costs of iECG screening, and treatment/outcome data from a United Kingdom cohort of 5,555 patients with incidentally detected asymptomatic AF. A total of 1,000 pharmacy customers aged ≥65 years (mean 76 ± 7 years; 44% male) were screened. Newly identified AF was found in 1.5% (95% CI, 0.8–2.5%); mean age 79 ± 6 years; all had CHA2DS2-VASc score ≥2. AF prevalence was 6.7% (67/1,000). The automated iECG algorithm showed 98.5% (CI, 92–100%) sensitivity for AF detection and 91.4% (CI, 89–93%) specificity. The incremental cost-effectiveness ratio of extending iECG screening into the community, based on 55% warfarin prescription adherence, would be $AUD5,988 (€3,142; $USD4,066) per Quality Adjusted Life Year gained and $AUD30,481 (€15,993; $USD20,695) for preventing one stroke. Sensitivity analysis indicated cost-effectiveness improved with increased treatment adherence. Screening with iECG in pharmacies with an automated algorithm is both feasible and cost-effective. The high and largely preventable stroke/thromboembolism risk of those with newly identified AF highlights the likely benefits of community AF screening. Guideline recommendation of community iECG AF screening should be considered.

Previous Presentation: This study was presented in part as an oral presentation at the Cardiac Society of Australia and New Zealand Conference; 9 August 2013; Sydney, Australia, abstract published in Heart Lung Circulation 2013;22:S223.

Trial registration: Australian New Zealand clinical trials registry: ACTRN12612000406808.

Screening for atrial fibrillation in hospitalised geriatric patients

OBJECTIVES

To assess whether daily short-term rhythm strip recordings on top of routine clinical care could increase the atrial fibrillation (AF) detection rate in the hospitalised elderly.

METHODS

A hand-held device storing a bipolar ECG during 1 min was used for daily rhythm recording in hospitalised elderly patients.

RESULTS

During 2 months, all patients admitted to the Department of Geriatric Medicine were screened (n=327). Five patients refused to participate in the study and 70 patients were unable to hold the device due to severe mental (n=46) or motor impairment (n=24). In the remaining 252 patients, 1582 recordings were successfully obtained after 1624 attempts with a median acquisition time of 1 min (min 1, max 9, IQR 1-2 min). The rhythm strips were not reliable interpretable due to artefacts in three patients or an implantable cardiac pulse generator in another 28 patients. Detailed clinical information was available in 214/221 patients. Mean age was 84±6 years. On top of 71 (33%) patients with AF identified by routine clinical care (history, n=64 or de novo detected during current hospitalisation, n=7), review of all rhythm strips identified another 28 patients (13%) with AF. All these patients had a CHA₂DS₂VASc score ≥2. A contraindication for anticoagulation was present in only 8/28 (25%) of identified patients.

CONCLUSIONS

On top of routine clinical care, daily short-term rhythm strip recordings identified another 13% of elderly hospitalised patients with AF, leading to an overall prevalence of 46% in hospitalised patients. This can have significant therapeutic implications with respect to initiation of anticoagulation.

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.

Stroke prevention in atrial fibrillation

Atrial fibrillation is found in a third of all ischaemic strokes, even more after post-stroke atrial fibrillation monitoring. Data from stroke registries show that both unknown and untreated or under treated atrial fibrillation is responsible for most of these strokes, which are often fatal or debilitating. Most could be prevented if efforts were directed towards detection of atrial fibrillation before stroke occurs, through screening or case finding, and treatment of all patients with atrial fibrillation at increased risk of stroke with well-controlled vitamin K antagonists or non-vitamin K antagonist anticoagulants. The default strategy should be to offer anticoagulant thromboprophylaxis to all patients with atrial fibrillation unless defined as truly low risk by simple validated risk scores, such as CHA2DS2-VASc. Assessment of bleeding risk using the HAS-BLED score should focus attention on reversible bleeding risk factors. Finally, patients need support from physicians and various other sources to start anticoagulant treatment and to ensure adherence to and persistence with treatment in the long term.