Detection of occult atrial fibrillation in patients with embolic stroke of uncertain source: a work in progress

Epidemiology and outcomes of intracerebral hemorrhage associated with oral anticoagulation over 10 years in a population-based stroke registry

BACKGROUND

Recent years have seen a change in the use of anticoagulants in the general population due to the availability of direct oral anticoagulants (DOACs) as an alternative to vitamin K antagonists (VKAs) and increased detection of atrial fibrillation. It is important to have updated epidemiological data to understand how this change is impacting on the occurrence and outcome of intracerebral hemorrhage (ICH).

PATIENTS AND METHODS

Our prospective population-based registry included patients with first-ever ICH occurring from January 2011 to December 2020. Oral anticoagulants (OAC)-related ICH was defined as an ICH occurring within 48 h from the intake of DOAC or VKAs, regardless of the measured international normalized ratio on hospital admission.

RESULTS

We included 748 first-ever ICH, of whom 108 (14.4%) were OAC-related. Specifically, 75 (69.4%) ICHs occurred on VKA and 33 (30.6%) on DOAC. The incidence of oral anticoagulation-associated intracerebral hemorrhage (OAC-ICH) was stable over time (p = 0.226). Among OAC-ICHs, we observed an increase in the overall incidence of DOAC-ICH (p for trend < 0.001) which overcome that of VKA-ICH in 2020 (incidence rate ratio (IRR) 4.71, 95% confidence interval (CI): 1.22-33.54; p = 0.022). Patients with OAC-ICH showed higher 30-day case fatality rates than those with non-OAC-ICH (48.1% vs 34.1%; p = 0.007).

CONCLUSION

No changes over time were detected in the incidence of OAC-ICH, but throughout the study period, there was a change in OAC-ICH from mostly VKA-related to mostly DOAC-related. Mortality in patients with OAC-ICH was higher than in patients with non-OAC-ICH.

Role of the score for the targeting of atrial fibrillation (STAF) combined with D-dimer in screening ischemic stroke patients with atrial fibrillation

Background

We aim to explore the effect of the score for the targeting of atrial fibrillation (STAF) combined with the serum D-dimer (DD) level in screening acute ischemic stroke patients with atrial fibrillation (AF).

Methods

This study is a retrospective case observation study. This study consecutively selected patients with acute ischemic stroke who were hospitalized in the Department of Neurology at Zhuhai Hospital Affiliated with Jinan University from February 2019 to February 2021. Venous blood was drawn from all patients within 24 hours of hospitalization for DD detection. In accordance with the medical records, the patients were classified into an AF group and a non-AF group and were scored according to the STAF standard. A combined test method was used to estimate the diagnostic screening value of the STAF combined with the DD value for acute ischemic stroke patients with AF.

Towards a new classification of atrial fibrillation detected after a stroke or a transient ischaemic attack

Globally, up to 1·5 million individuals with ischaemic stroke or transient ischaemic attack can be newly diagnosed with atrial fibrillation per year. In the past decade, evidence has accumulated supporting the notion that atrial fibrillation first detected after a stroke or transient ischaemic attack differs from atrial fibrillation known before the occurrence of as stroke. Atrial fibrillation detected after stroke is associated with a lower prevalence of risk factors, cardiovascular comorbidities, and atrial cardiomyopathy than atrial fibrillation known before stroke occurrence. These differences might explain why it is associated with a lower risk of recurrence of ischaemic stroke than known atrial fibrillation. Patients with ischaemic stroke or transient ischaemic attack can be classified in three categories: no atrial fibrillation, known atrial fibrillation before stroke occurrence, and atrial fibrillation detected after stroke. This classification could harmonise future research in the field and help to understand the role of prolonged cardiac monitoring for secondary stroke prevention with application of a personalised risk-based approach to the selection of patients for anticoagulation.

Cost-effectiveness of insertable cardiac monitors for diagnosis of atrial fibrillation in cryptogenic stroke in Australia

INTRODUCTION

Detection of atrial fibrillation (AF) is required to initiate oral anticoagulation (OAC) after cryptogenic stroke (CS). However, paroxysmal AF can be difficult to diagnose with short term cardiac monitoring. Taking an Australian payer perspective, we evaluated whether long-term continuous monitoring for 3 years with an insertable cardiac monitor (ICM) is cost-effective for preventing recurrent stroke in patients with CS.

METHODS

A lifetime Markov model was developed to simulate the follow-up of patients, comparing long-term continuous monitoring with an ICM to monitoring by conventional care. We used a linked evidence approach to estimate the rates of recurrent stroke when AF detection leads to initiation of OAC, as detected using ICM during the lifetime of the device or as detected using usual care. All diagnostic and patient management costs were modeled. Other model inputs were determined by literature review. Probabilistic sensitivity analysis (PSA) was undertaken to explore the effect of parameter uncertainty according to CHADS2 score and OAC treatment effect.

RESULTS

In the base-case analysis, the model predicted an incremental cost-effectiveness ratio (ICER) of A$29 570 per quality-adjusted life year (QALY). Among CHADS2 subgroups analyses, the ICER ranged from A$26 342/QALY (CHADS2 = 6) to A$42 967/QALY (CHADS2 = 2). PSA suggested that the probabilities of ICM strategy being cost-effective were 53.4% and 78.7%, at thresholds of $30 000 (highly cost-effective) and $50 000 per QALY (cost-effective), respectively.

CONCLUSIONS

Long-term continuous monitoring with an ICM is a cost-effective intervention to prevent recurrent stroke in patients following CS in the Australian context.

Knots to untie: anticoagulant and antiarrhythmic therapy after ablation for atrial fibrillation

The continuation or otherwise of anticoagulant and antiarrhythmic therapy after ablation of atrial fibrillation (AF) is one of the main aspects still to be defined in the electrophysiological field. The currently available data do not allow the assumption of certain positions due to the lack of randomized studies on the subject. With regard to anticoagulant therapy, however, the suggestion of the guidelines to assess more the risk profile than the result of the ablation and consequently to prescribe anticoagulant treatment to all patients with CHADSVASc ≥2 seems acceptable. Its use in the first two or three months after the procedure appears reasonable; however, keeping in mind that the objective of this strategy is limited to the prevention of early recurrences only. More prolonged use of antiarrhythmics seems to be more promising, but further data are necessary before it can be recommended routinely. The ablation of AF is a therapy that is widely spreading and its use is continuously growing. Since it is a recently introduced method, not everything is still clear about it. The continuation or not of anticoagulant and antiarrhythmic therapy after ablation for AF is one of the main aspects yet to be defined.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Cardiac diagnostic work-up of ischaemic stroke

Cardioembolic sources account for 20-30% of ischaemic strokes and are important to identify considering their prognostic and therapeutic implications. During the past years, new developments have been made in the cardiac diagnostic evaluation and management of patients with ischaemic stroke, especially regarding strokes of unknown aetiology. These recent advances have had a major impact on our understanding of embolic strokes, their diagnostic work-up, and clinical management. Herein, we propose a cardiac diagnostic work-up scheme for patients with ischaemic stroke from definite cardioembolic sources and embolic strokes of undetermined source.

A study to assess a novel automated electrocardiogram technology in screening for atrial fibrillation

INTRODUCTION

Atrial fibrillation is often asymptomatic and un-diagnosed in the community resulting in an increased risk of heart failure and stroke to those patients. We evaluated the effectiveness, tolerability, and accuracy of a novel six-channel electrocardiogram digital-health screening device, the RhythmPad, for the detection of atrial fibrillation.

METHODS

Seven hundred and fifty-two participants attending the cardiology department were recruited. Two recordings were taken-a six-lead electrocardiogram using the RhythmPad device and a standard 12-lead electrocardiogram. Recorded traces were analyzed by two blinded cardiologists. The computer-generated automated diagnostic reports from both systems were also compared. Post-participation feedback was obtained from study participants using a three-part questionnaire.

RESULTS

The sensitivity of the six-lead electrocardiogram compared to the 12-lead electrocardiogram, analyzed by two blinded cardiologists, for the detection of normal sinus rhythm was 95.9%, with a specificity of 97.2%. The sensitivity for the detection of atrial fibrillation using the six-lead ECG was 93.4%, with specificity 96.8%. The six-lead automated diagnostic report had a sensitivity and specificity of 97.5% and 98.6%, respectively, for correctly diagnosing normal sinus rhythm. For the correct diagnosis of atrial fibrillation, the six-lead automated diagnostic report had a sensitivity and specificity of 95.4% and 98.8%, respectively. A total of 95.4% of participants found RhythmPad to be comfortable, with only 0.5% preferring the 12-lead ECG device in comparison to six-lead ECG acquisitions.

CONCLUSION

The RhythmPad digital health device and its automated diagnostic report were highly accurate in detecting atrial fibrillation when compared to a standard 12-lead electrocardiogram.

Duration of Implantable Cardiac Monitoring and Detection of Atrial Fibrillation in Ischemic Stroke Patients: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Current guidelines do not provide firm directions on atrial fibrillation (AF) screening after ischemic stroke (IS). We sought to investigate the association of implantable cardiac monitoring (ICM) duration with the yield of AF detection in IS patients.

METHODS

We included studies reporting AF detection rates by ICM in IS patients with negative initial AF screening. We excluded studies reporting prolonged cardiac monitoring with devices other than ICM, not providing AF detection rates or monitoring duration, and reporting overlapping data for the same population. The random-effects model was used for all pooled estimates and meta-regression analyses.

RESULTS

We included 28 studies (4,531 patients, mean age 65 years). In meta-regression analyses, the proportion of AF detection by ICM was independently associated with monitoring duration (coefficient=0.015; 95% confidence interval [CI], 0.005 to 0.024) and mean patient age (coefficient=0.009; 95% CI, 0.003 to 0.015). No associations were detected with other patient characteristics, including IS subtype (cryptogenic vs. embolic stroke of undetermined source) or time from IS onset to CM implantation. In subgroup analyses, significant differences (P<0.001) in the AF detection rates were found for ICM duration (<6 months: 5% [95% CI, 3% to 6%]; ≥6 and ≤12 months: 21% [95% CI, 16% to 25%]; >12 and ≤24 months: 26% [95% CI, 22% to 31%]; >24 months: 34% [95% CI, 29% to 39%]).

CONCLUSION

s Extended duration of ICM monitoring and increased patient age are factors that substantially increase AF detection in IS patients with initial negative AF screening.

Atrial fibrillation in cryptogenic stroke and transient ischaemic attack - The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study: Rationale and design

Purpose

Paroxysmal atrial fibrillation is often suspected as a probable cause of cryptogenic stroke. Continuous long-term ECG monitoring using insertable cardiac monitors is a clinically effective technique to screen for atrial fibrillation and superior to conventional follow-up in cryptogenic stroke. However, more studies are needed to identify factors which can help selecting patients with the highest possibility of detecting atrial fibrillation with prolonged rhythm monitoring. The clinical relevance of short-term atrial fibrillation, the need for medical intervention and the evaluation as to whether intervention results in improved clinical outcomes should be assessed.

Method

The Nordic Atrial Fibrillation and Stroke Study is an international, multicentre, prospective, observational trial evaluating the occurrence of occult atrial fibrillation in cryptogenic stroke and transient ischaemic attack. Patients with cryptogenic stroke or transient ischaemic attack from the Nordic countries are included and will have the Reveal LINQ® Insertable cardiac monitor system implanted for 12 months for atrial fibrillation detection. Biomarkers which can be used as predictors for atrial fibrillation and may identify patients, who could derive the most clinical benefit from the detection of atrial fibrillation by prolonged monitoring, are being studied.

Conclusion

The primary endpoint is atrial fibrillation burden within 12 months of continuous rhythm monitoring. Secondary endpoints are atrial fibrillation burden within six months, levels of biomarkers predicting atrial fibrillation, CHA₂DS₂-VASc score, incidence of recurrent stroke or transient ischaemic attack, use of anticoagulation and antiarrhythmic drugs, and quality of life measurements. The clinical follow-up period is 12 months. The study started in 2017 and the completion is expected at the end of 2020.

The Next 10 Years in Atrial Fibrillation

Predicting future advancements in arrhythmia management – specifically AF – with any certainty is impossible. The clinical approach to AF has changed markedly since the turn of the century in ways that could never have been foreseen, but the current methods of identification and treatment remain far from perfect. Over the next decade we expect significant continued progress in AF management. However, if asked to forecast the future, we consider it wise to predict advancements in the nearer term. We believe there will be widespread expansion in digital health and mobile devices, altering the way we detect and monitor the arrhythmia. We expect substantial growth in advanced MRI to aid in early detection, evaluation, and possibly non-invasive treatment of AF substrate. We imagine there will be increasing focus on individual populations to identify at-risk groups and personalize early management. We also anticipate improvement in anticoagulation employment and left atrial appendage modification. Finally, recognizing the benefit of improvement in modifiable risk factors such as mandatory tobacco cessation and weight loss in obese patients, we predict that reimbursement will be dependent on successfully addressing modifiable risk. For now, several questions remain unanswered, and while no one can predict the next 10 years in AF, there is, without doubt, an abundance of opportunity.

Predictive modeling in urgent care: a comparative study of machine learning approaches

OBJECTIVE

The growing availability of rich clinical data such as patients' electronic health records provide great opportunities to address a broad range of real-world questions in medicine. At the same time, artificial intelligence and machine learning (ML)-based approaches have shown great premise on extracting insights from those data and helping with various clinical problems. The goal of this study is to conduct a systematic comparative study of different ML algorithms for several predictive modeling problems in urgent care.

DESIGN

We assess the performance of 4 benchmark prediction tasks (eg mortality and prediction, differential diagnostics, and disease marker discovery) using medical histories, physiological time-series, and demographics data from the Medical Information Mart for Intensive Care (MIMIC-III) database.

MEASUREMENTS

For each given task, performance was estimated using standard measures including the area under the receiver operating characteristic (AUC) curve, F-1 score, sensitivity, and specificity. Microaveraged AUC was used for multiclass classification models.

RESULTS AND DISCUSSION

Our results suggest that recurrent neural networks show the most promise in mortality prediction where temporal patterns in physiologic features alone can capture in-hospital mortality risk (AUC > 0.90). Temporal models did not provide additional benefit compared to deep models in differential diagnostics. When comparing the training-testing behaviors of readmission and mortality models, we illustrate that readmission risk may be independent of patient stability at discharge. We also introduce a multiclass prediction scheme for length of stay which preserves sensitivity and AUC with outliers of increasing duration despite decrease in sample size.

Atrial fibrillation and cryptogenic stroke. What is the current evidence? Role of electrocardiographic monitoring

The diagnosis of cryptogenic stroke is made by exclusion. However, current evidence supports the role of atrial fibrillation episodes as a cause of this condition. Prospective data have demonstrated the benefits of long‐term electrocardiographic monitoring to identify atrial fibrillation in association with cryptogenic stroke. This aim of this article was to analyze the contemporary evidence for the possible relationship between atrial fibrillation and cryptogenic stroke and the role of continuous electrocardiographic monitoring to clarify this hypothesis.

The complexity of atrial fibrillation newly diagnosed after ischemic stroke and transient ischemic attack: advances and uncertainties

Purpose of review

Atrial fibrillation is being increasingly diagnosed after ischemic stroke and transient ischemic attack (TIA). Patient characteristics, frequency and duration of paroxysms, and the risk of recurrent ischemic stroke associated with atrial fibrillation detected after stroke and TIA (AFDAS) may differ from atrial fibrillation already known before stroke occurrence. We aim to summarize major recent advances in the field, in the context of prior evidence, and to identify areas of uncertainty to be addressed in future research.

Recent findings

Half of all atrial fibrillations in ischemic stroke and TIA patients are AFDAS, and most of them are asymptomatic. Over 50% of AFDAS paroxysms last less than 30 s. The rapid initiation of cardiac monitoring and its duration are crucial for its timely and effective detection. AFDAS comprises a heterogeneous mix of atrial fibrillation, possibly including cardiogenic and neurogenic types, and a mix of both. Over 25 single markers and at least 10 scores have been proposed as predictors of AFDAS. However, there are considerable inconsistencies across studies. The role of AFDAS burden and its associated risk of stroke recurrence have not yet been investigated.

Summary

AFDAS may differ from atrial fibrillation known before stroke in several clinical dimensions, which are important for optimal patient care strategies. Many questions remain unanswered. Neurogenic and cardiogenic AFDAS need to be characterized, as it may be possible to avoid some neurogenic cases by initiating timely preventive treatments. AFDAS burden may differ in ischemic stroke and TIA patients, with distinctive diagnostic and treatment implications. The prognosis of AFDAS and its risk of recurrent stroke are still unknown; therefore, it is uncertain whether AFDAS patients should be treated with oral anticoagulants.

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.

Stroke Prevention for Patients with Atrial Fibrillation: Beyond the Guidelines

Atrial fibrillation (AF) is the most common serious heart rhythm disorder, with a lifetime incidence of 1 in 4 for patients >40 years of age[1]. AF is a major cause of death and disability, as it is associated with a 4-5 fold increase in the risk of ischemic stroke[2]. In patients with AF, oral anticoagulation (OAC) therapy can reduce the risk of stroke by about two-thirds and the risk of all-cause mortality by approximately one-quarter, but is associated with an increased risk of bleeding[3], [4]. Atrial fibrillation (AF) is the most common serious heart rhythm disorder and is associated with an increased risk of ischemic stroke. This risk can be moderated with oral anticoagulation therapy, but the decision to do so must be balanced against the risks of bleeding. Herein, we discuss three emerging areas where more high-quality evidence is required to guide risk stratification: 1) the relationships between the pattern and burden of AF and stroke 2) the risk conferred by short episodes of device-detected "sub-clinical" atrial fibrillation (SCAF) and 3) the significance of AF that occurs transiently with stress (AFOTS), as is often detected during medical illness or after surgery. Risk stratification is important to identify patients with AF who can benefit from OAC therapy. There are, however, several common clinical scenarios where guidelines do not yet provide direction for stroke prevention; or do so based on limited high-quality evidence.

Atrial fibrillation detected by external loop recording for seven days or two-day simultaneous Holter recording: A comparison in patients with ischemic stroke or transient ischemic attack

Atrial fibrillation (AF) is the most common cardiac cause of ischemic stroke and transient ischemic attack (IS/TIA).

AIM

To compare the diagnostic value of seven-day external loop recording (ELR) and two-day Holter recording for detecting AF after IS/TIA.

METHODS

191 IS/TIA patients without AF history. Endpoint was AF >30s. We started two-day Holter recording and seven-day ELR simultaneously.

RESULTS

Seven-day ELR and two-day Holter recording detected the same three AF patients. ELR detected another six patients with AF adjudicated by cardiologists, four detections after Holter (3 vs. 7, p=0.125) and two false-positive detections during Holter. Seven-day ELR automatically classified 50/191 patients (26%) with AF, but only 7/50 (14%) were confirmed as AF by cardiologists.

CONCLUSION

Seven-day ELR did not detect significantly more patients with AF than two-day Holter recording. 86% of patients with ELR-classified AF were false positives, indicating a poor performance of the automatic AF detection algorithm used.

Atrial Fibrillation Monitoring in Cryptogenic Stroke: the Gaps Between Evidence and Practice

Identifying occult paroxysmal atrial fibrillation as the etiology of cryptogenic stroke has been a top research priority in the past decade. This is because prompt initiation of anticoagulation has significantly decreased subsequent stroke risk. Available evidence suggests that prolonged cardiac monitoring after stroke increases the likelihood of detecting atrial fibrillation. However, further research is required to fill in the gaps in regard to the optimal period of monitoring, candidates for monitoring, etc. Here, we review the current evidence supporting the use of prolonged monitoring for cryptogenic stroke patients and discuss the directions of future research.