Detection Of Subclinical Atrial Fibrillation Research Articles

Subclinical atrial fibrillation in embolic stroke of undetermined source: Management and stroke recurrence

Subclinical atrial fibrillation (SAF) represents the most prevalent underlying etiology detected after an embolic stroke of undetermined source (ESUS). Investigating SAF is strongly recommended during the diagnostic work-up. The efficacy of oral anticoagulant (OAC) therapy in reducing the risk of stroke recurrence post-SAF detection remains a conundrum. Thus, our study aimed to analyze the management of secondary antithrombotic prophylaxis and the rate of 12-month stroke recurrence in real-life ESUS patients. We retrospectively analyzed clinical, radiographic, and echocardiographic findings of patients with ESUS who underwent non-implantable 2-week electrocardiogram (ECG) monitoring after discharge. Episodes of SAF of any duration were considered diagnostic. Antithrombotic treatment at hospital discharge and after ECG monitoring, as well as 12-month recurrence, were registered. We compared the rate of stroke recurrence between patients with and without detection of SAF. One hundred and fifty-nine patients (75 females) with a median age of 73.5 (interquartile range [IQR] = 66.75 – 79) years represented the study population. At hospital discharge, 96.9% of patients received antiplatelet therapy as secondary antithrombotic prophylaxis. SAF was detected in 82 patients (51.5%), and OAC was prescribed in 98.6% of them. The median time from stroke onset to OAC prescription was 143 (IQR = 94 – 178) days. Overall, 12-month stroke recurrence occurred in eight patients (5%). The stroke recurrence rate was lower in patients prescribed OAC compared with those not prescribed it, although the difference was not significant (3.7% vs. 6.25%; P = 0.7202). In our study, OACs prescribed post-SAF detection in patients with ESUS reduced, but not significantly, the risk of stroke recurrence. Future research and prospective multicenter studies are warranted.

Anticoagulation-Associated Bleeding in Patients Screened for Atrial Fibrillation versus Usual Care-A Post Hoc Analysis from the LOOP Study.

Background Atrial fibrillation (AF) prevalence is rising; however, data on the bleeding risks associated with the detection of subclinical AF are needed. Objective Our objective was to determine the bleeding increment associated with implantable loop recorder (ILR) screening for subclinical AF and subsequent anticoagulation initiation compared with usual care. Methods This post hoc study utilized LOOP trial data from 6,004 elderly patients with stroke risks randomized to either ILR ( n = 1,503) or usual care ( n = 4,503). The mean follow-up time was 64.5 months, and none were lost to follow-up. The primary exposure was the initiation of oral anticoagulation, and the main outcome was the risk of major bleeding events following initiation of oral anticoagulants (OACs), determined by time-dependent cox regression. Second, we investigated antithrombotic prescription patterns and major bleeding events after antiplatelet treatment and in subgroups. Results OAC was initiated in 1,019 participants with a mean age (years) of 78.8 (± 4.67) in control versus 77.0 (± 4.84) in ILR, p < 0.0001. Altogether did 202 participants end or pause OAC treatment. Among AF patients (n = 910) had 40 (28%) completely ended OAC and 105 (72%) temporarily paused OAC during follow-up. Major bleeding events totaled 221 (3.7%). Forty-seven major bleeding events followed an OAC initiation in 1,019 participants (4.6%); 26 versus 21 events in the control and ILR groups, respectively. The hazard ratio (HR) for major bleeding after OAC initiation compared with before initiation was 2.08 (1.50-2.90) p < 0.0001 overall, 2.81 (1.82-4.34) p < 0.0001 for control and 1.32 (0.78-2.23) p = 0.31 for the ILR group ( p = 0.07 for interaction). Antiplatelet treatment resulted in an overall adjusted HR of 1.3 (0.96-1.75) p = 0.09. For OAC users aged ≥75 years in the ILR group, the rate of major bleeding was 1.73 (0.92-2.96) compared with 0.84 (0.36-1.66) for an age <75 years, and the rate of the corresponding control subgroup aged ≥75 years was 2.20 (1.23-3.63) compared with 1.64 (0.82-2.93) for an age <75 years. Conclusion The individual risk of major bleeding increased twofold after initiation of oral anticoagulation for all patients in this study. However, the patients screened for subclinical AF did not have a higher bleeding risk after initiation of anticoagulation compared with those in usual care. Trial Registration: The LOOP study is registered at ClinicalTrials.gov, identifier: NCT020364 50.

Clinical predictive scores for detection of sub-clinical atrial fibrillation after cryptogenic or embolic stroke of undetermined source: A brief systematic review

Subclinical atrial fibrillation (SAF) is the primary underlying cause of cryptogenic stroke (CS) or embolic stroke of undetermined source (ESUS), particularly in patients over 65 years of age. Therefore, it is strongly recommended screening for SAF in these patients. The development of tools designed to determine the priority of SAF screening is essential for optimizing the diagnostic workup. The aim of our study was to investigate the clinical predictive scores available for SAF detection in patients with CS or ESUS. We gathered data from articles published on the PubMed database from January 1, 2000, to January 31, 2023. Our search yielded eight scores for CS and three for ESUS. SAF diagnosis was established using various methods: 12-lead ECG or 24-h ECG monitoring during 1-year follow-up in three scores; 72-h non-implantable ECG monitoring in two scores; 2 or 3-week non-implantable ECG monitoring in three scores; and implantable ECG monitoring in one score. In two scores, ECG monitoring was performed using a non-implantable and/or implantable loop recorder. Overall, the rate of SAF detection was approximately 6% when using devices for monitoring lasting no more than 72 h and increased to nearly 22% employing 2 or 3-week non-implantable or implantable devices. SAF was defined differently in various scores; five scores considered any episode, even if shorter than 30 s, while six scores required episodes to last at least 30 s. Advanced age was included as a variable in 10 of 11 scores, whereas left atrial enlargement, premature atrial beats, and brain computed tomography characteristics were features in four scores. The area under the curve values of these scores ranged from 0.72 to 0.94. In conclusion, it is still challenging to put the currently available clinical scores to use due to a lack of validation. To provide more comprehensive guidance, it is essential to conduct large prospective multicenter trials in the future.

Mobile Electrocardiograms in the Detection of Subclinical Atrial Fibrillation in High-Risk Outpatient Populations: Protocol for an Observational Study.

Single-lead, smartphone-based mobile electrocardiograms (ECGs) have the potential to provide a noninvasive, rapid, and cost-effective means of screening for atrial fibrillation (AFib) in outpatient settings. AFib has been associated with various comorbid diseases that prompt further investigation and screening methodologies for at-risk populations. A simple 30-second sinus rhythm strip from the KardiaMobile ECG (AliveCor) can provide an effective screen for cardiac rhythm abnormalities. The aim of this study is to demonstrate the feasibility of performing Kardia-enabled ECG recordings routinely in outpatient settings in high-risk populations and its potential use in uncovering previous undiagnosed cases of AFib. Specific aim 1 is to determine the feasibility and accuracy of performing routine cardiac rhythm sampling in patients deemed at high risk for AFib. Specific aim 2 is to determine whether routine rhythm sampling in outpatient clinics with high-risk patients can be used cost-effectively in an outpatient clinic without increasing the time it takes for the patient to be seen by a physician. Participants were recruited across 6 clinic sites across the University of Florida Health Network: University of Florida Health Nephrology, Sleep Center, Ophthalmology, Urology, Neurology, and Pre-Surgical. Participants, aged 18-99 years, who agreed to partake in the study were given a consent form and completed a questionnaire regarding their past medical history and risk factors for cardiovascular disease. Single-lead, 30-second ECGs were taken by the KardiaMobile ECG device. If patients are found to have newly diagnosed AFib, the attending physician is notified, and a 12-lead ECG or standard ECG equivalent will be ordered. As of March 1, 2024, a total of 2339 participants have been enrolled. Of the data collected thus far, the KardiaMobile rhythm strip reported 381 abnormal readings, which are pending analysis from a cardiologist. A total of 78 readings were labeled as possible AFib, 159 readings were labeled unclassified, and 49 were unreadable. Of note, the average age of participants was 61 (SD 10.25) years, and the average self-reported weight was 194 (SD 14.26) pounds. Additionally, 1572 (67.25%) participants report not regularly seeing a cardiologist. Regarding feasibility, the average length of enrolling a patient into the study was 3:30 (SD 0.5) minutes after informed consent was completed, and medical staff across clinic sites (n=25) reported 9 of 10 level of satisfaction with the impact of the screening on clinic flow. Preliminary data show promise regarding the feasibility of using KardiaMobile ECGs for the screening of AFib and prevention of cardiological disease in vulnerable outpatient populations. The use of a single-lead mobile ECG strip can serve as a low-cost, effective AFib screen for implementation across free clinics attempting to provide increased health care accessibility. DERR1-10.2196/52647.

Active monitoring for atrial fibrillation (AMALFI): a streamlined randomised controlled trial of remote screening for subclinical atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): National Institute for Health and Care Research Oxford Biomedical Research Centre ECG patches (and respective monitoring data analysis) were granted free of charge by the manufacturer (iRhythm) Background Incidence of stroke could be reduced by detection of subclinical atrial fibrillation (AF) and appropriate anticoagulation. Opportunistic screening by pulse-taking or ECG is recommended by some international guidelines. In contrast, there is uncertainty regarding the benefits and harms of systematic screening across populations and/or using longer monitoring durations. Purpose To assess if screening using a one-off single-lead continuous non-invasive ECG patch worn for 14 days increases AF detection at 2.5 years compared to standard care, and whether this approach is cost-effective. Methods AMALFI is an ongoing mail-based open-label randomised controlled trial of remote AF screening in England. Streamlined design includes integration with national electronic health data and care pathways for participant identification, invitation, and management. The target population are individuals aged ≥65 years with CHA2DS2VASc score of ≥3 in men and ≥4 in women, and with no prior history of AF or allergy to latex. Participants in the intervention arm self-apply the ECG patch and return it for analysis after 14 days. AF findings (duration ≥30 seconds at any rate) are communicated to primary care physicians, with further clinical management at their discretion. Participants in the control arm receive usual care (which is expected to include opportunistic AF screening). The primary outcome is the proportion of participants with newly-detected AF recorded in primary care electronic health records in each group at 2.5 years after randomisation. Results From 2019 to 2022, AMALFI invited 22,188 people, of whom 5,040 (23%) were randomised. Baseline characteristics included age 77±6 years, 47% female, and median CHA2SD2VASc score 3 (Table 1). Of 2520 individuals randomised to the intervention, 2127 (84%) wore and returned the patch. Median wear time was 13.9 days and median proportion of time analysable was 98.8%. AF was present in 102 patch reports, representing 4.8% of reports received and 4% of the intervention arm (in line with a priori estimates for power calculations for the primary outcome); median AF burden was 11.3%. AF was present at commencement of recording in 40% of these reports, by the end of the first day in 58%, and by the end of the first week in 83% (Figure 1). Incidental findings included supraventricular tachycardia (in 90% of reports), non-sustained ventricular tachycardia (VT; in 32%), sustained VT (in 0.1%), Mobitz II/high-grade/3rd degree AV block (in 1.1%), and pauses &amp;gt;6s (in 0.3%). Conclusion AMALFI’s innovative design facilitated recruitment and demonstrates that a remote ECG patch-based AF screening strategy is feasible, resulting in a new diagnosis of AF in ~4% of individuals selected due to moderate-to-high clinical stroke risk. Longer term follow-up will provide data on the incremental value and cost-effectiveness of AF diagnosis by systematic screening compared to routine opportunistic detection.

Clinical and radiological predictive factors of silent AF in ESUS stroke

A quarter of cerebral infarctions remain without etiology (ESUS: embolic stroke of unknown source) with a risk of recurrence under anti-platelet therapy greater than 4% per year. In this population, the challenge is the detection of subclinical atrial fibrillation (AF), the incidence of which could reach 25%. The efficacy of the probabilistic anticoagulation strategy has not been demonstrated in this population making it necessary to identify ESUS patients at high risk of subclinical AF. The aim of this study is to determine clinical and radiological predictive factors of silent AF in ESUS stroke. Monocentric descriptive and analytical historical cohort study conducted at the Neurology Department between January 2016 and December 2020. Three hundred Esus patients were included. In our study 42/300 (14%) patients had at least one episode of AF (> 30 s). In univariate analysis, the variables significantly associated with slower AF in ESUS-type stroke were age greater than or equal to 60 years (P = 0.004, OR = 3.76), female gender (P = 0.045, OR = 1.94), coronary artery disease (P = 0.008, OR = 3.43), previous stroke (P = 0.007, OR = 2.67), stroke of different territory or age (P = 0.031, OR = 2.65), stroke on awakening (P < 10−3, OR = 5.95), higher NIHSS score on admission (P = 0.023, OR = 1.08), lower NIHSS score on discharge (P = 0.031, OR = 0.89), older cerebellar stroke (P < 10−3, OR = 14.16). In multivariate analysis, higher NIHSS score at admission (P = 0.023, OR = 1.08), and lower NIHSS score (P = 0.031, OR = 0.89) at discharge appeared as independent predictors of the occurrence of a subclinical AF episode. In this cohort of ESUS patients, several factors appeared to be predictive of subclinical AF. The subgroup of ESUS patients with these factors appeared to benefit from probabilistic anticoagulation in preventing recurrent cerebral infarction. A therapeutic trial should confirm this hypothesis.

Electrocardiographic and echographic predictive factors of silent AF in ESUS stroke

Stroke is a major public health problem, the leading cause of acquired disability in adults and the third leading cause of death worldwide. Ischaemic stroke accounts for 80% of all strokes. Approximately 20% of DVAs are associated with atrial fibrillation (AF). However, 25% remain of undetermined origin (ESUS) with a risk of recurrence under anti-platelet therapy greater than 4% per year. In this population, the challenge is the detection of subclinical atrial fibrillation (AF), the incidence of which could reach 25%. The effectiveness of the probabilistic anticoagulation strategy has not been demonstrated in this population, making it necessary to identify ESUS patients at high risk of subclinical AF. The aim of this study is to determine the incidence and the electrocardiographic and echographic predictive factors of silent AF in ESUS stroke. Monocentric descriptive and analytical historical cohort study conducted at the Neurology Department between January 2016 and December 2020. Three hundred Esus patients were included. In our study, 42/300 (14%) patients had at least one episode of AF (> 30 s). In univariate analysis, the variables significantly associated with sluggish AF in ESUS-type stroke were age greater than or equal to 60 years (P = 0.004, OR = 3.76), female gender (P = 0.045, OR = 1.94), P-wave markers (abnormal axis, prolonged duration), P-wave dispersion (P < 10−3), a high number of supraventricular extrasystoles (P < 10−3, OR = 1.007), OG dilatation (P < 10−3, OR = 1.61) and diastolic dysfunction (P < 10−3, OR = 30.25). In multivariate analysis, p-wave dispersion (P < 10−3, OR = 57.77), number of SVSEs > 500/24 h (P < 10−3, OR = 185.83), and left atrial area > 20 cm2 (P < 10−3, OR = 74.7) appeared to be independent predictors of the occurrence of a subclinical AF episode. In this cohort of ESUS patients, several factors appeared to be predictive of subclinical AF. This result is consistent with the finding of several studies that the subgroup of ESUS patients with these factors appeared to benefit from probabilistic anticoagulation in preventing cerebral infarct recurrence.

Prolonged cardiac monitoring for stroke prevention: A systematic review and meta-analysis of randomized-controlled clinical trials.

Prolonged cardiac monitoring (PCM) substantially improves the detection of subclinical atrial fibrillation (AF) among patients with history of ischemic stroke (IS), leading to prompt initiation of anticoagulants. However, whether PCM may lead to IS prevention remains equivocal. In this systematic review and meta-analysis, randomized-controlled clinical trials (RCTs) reporting IS rates among patients with known cardiovascular risk factors, including but not limited to history of IS, who received PCM for more than 7 days versus more conservative cardiac rhythm monitoring methods were pooled. Seven RCTs were included comprising a total of 9048 patients with at least one known cardiovascular risk factor that underwent cardiac rhythm monitoring. PCM was associated with reduction of IS occurrence compared to conventional monitoring (Risk Ratio: 0.76; 95% CI: 0.59-0.96; I 2 = 0%). This association was also significant in the subgroup of RCTs investigating implantable cardiac monitoring (Risk Ratio: 0.75; 95% CI: 0.58-0.97; I 2 = 0%). However, when RCTs assessing PCM in both primary and secondary prevention settings were excluded or when RCTs investigating PCM with a duration of 7 days or less were included, the association between PCM and reduction of IS did not retain its statistical significance. Regarding the secondary outcomes, PCM was related to higher likelihood for AF detection and anticoagulant initiation. No association was documented between PCM and IS/transient ischemic attack occurrence, all-cause mortality, intracranial hemorrhage, or major bleeding. PCM may represent an effective stroke prevention strategy in selected patients. Additional RCTs are warranted to validate the robustness of the reported associations.

Multiparametric identification of subclinical atrial fibrillation after an embolic stroke of undetermined source.

Subclinical atrial fibrillation (SCAF) may represent a cause of embolic stroke of undetermined source (ESUS) and its detection has important implications for secondary prevention with anticoagulation. Indications to implantable cardiac monitors (ICM) include SCAF detection. The aims of this study were to (1) evaluate the frequency of ICM-detected SCAF; (2) determine predictors of SCAF; and (3) identify patients who would benefit most from ICM implantation. Between February 2017 and November 2020, all consecutive patients referred for ICM implantation after a diagnosis of ESUS and without previous history of atrial fibrillation or atrial flutter were included in this study. SCAF was diagnosed if the ICM electrogram demonstrated an episode of irregularly irregular rhythm without distinct P waves lasting > 2min. We enrolled 109 patients (age 66, SD = 13years; 36% females). During a median follow-up of 19.2 (IQR 11.0-27.5) months, SCAF episodes were detected in 36 (33%) patients. Only abnormal P wave terminal force in lead V1, left atrial end-systolic indexed volume > 34ml/m2, and BMI > 25kg/m2 were independently associated with an increased risk of SCAF (HR 2.44, 95% CI 1.14-5.21, p = 0.021; HR 2.39, 95% CI 1.11-5.13, p = 0.026; and HR 2.64, 95% CI 1.06-6.49, p = 0.036 respectively). The ROC curve showed that the presence of all three parameters had the best accuracy (74%) to predict SCAF detection (sensitivity 39%, specificity 91%). A multiparametric evaluation has the best accuracy to predict SCAF in ESUS patients and may help identifying those who would benefit most from ICM.

A pragmatic approach to detection of atrial fibrillation and choice of a secondary prevention program in a patient with cryptogenic embolic stroke: Presentation of a clinical case taking into account the current state of the problem

The article presents a clinical example of using the diagnostic algorithm for identifying the criteria for atrial cardiopathy in a patient with cryptogenic stroke. This clinical case required prolonged ECG monitoring, detection of subclinical atrial fibrillation, and subsequent collegial establishment of indications for initiation of anticoagulant therapy taking into account the high risk of recurrent stroke.

Prediction of occult atrial fibrillation in patients after cryptogenic stroke and transient ischaemic attack: PROACTIA.

Studies with implantable cardiac monitors (ICMs) show that one-third of patients with cryptogenic stroke/transient ischaemic attack (TIA) have episodes of subclinical atrial fibrillation (SCAF) and benefit switching from antiplatelet- to anticoagulant therapy. However, ICMs are costly and resource demanding. We aimed to build a score based on participant's baseline characteristics that could assess individual risk of SCAF. In a prospective study, 236 eligible patients with a final diagnosis of cryptogenic stroke/TIA had an ICM implantated during the index hospitalization. Pre-specified evaluated variables were: CHA2DS2-VASc, P-wave duration, P-wave morphology, premature atrial beats (PAC)/24 h, supraventricular tachycardia/24 h, left atrial end-systolic volume index (LAVI), Troponin-T, NT-proBNP, and D-dimer. SCAF was detected in 84 patients (36%). All pre-specified variables were significantly associated with SCAF detection in univariate analysis. P-wave duration, followed by PAC/24 h, NT-proBNP, and LAVI, had the largest ratio of SCAF prevalence between its upper and lower quartiles (3.3, vs. 3.2, vs. 3.1 vs. 2.8, respectively). However, in a multivariate analysis, only PAC/24t, P-wave duration, P-wave morphology, and LAVIs remained significant predictors and were included in the PROACTIA score. Subclinical atrial fibrillation prevalence was 75% in the highest vs. 10% in the lowest quartile of the PROACTIA score with a 10-fold higher number of patients with an atrial fibrillation burden >6 h in the highest vs. the lowest quartile. The PROACTIA score can identify patients with cryptogenic stroke/TIA at risk of subsequent SCAF detection. The large difference in SCAF prevalence between groups may provide a basis for future tailored therapy. Clinical Trial Registration: ClinicalTrials.gov; NCT02725944.

The utilization of atrial sensing dipole in single lead implantable cardioverter defibrillator for detection of new-onset atrial high-rate episodes or subclinical atrial fibrillation: A systematic review and meta-analysis.

This meta‐analysis aims to evaluate the performance of atrial sensing dipole in single lead implantable cardioverter defibrillator (VDD‐ICD) recipients in particular diagnosing new‐onset atrial high‐rate episodes (AHREs) defined as rate threshold of 200 beats per minute, or subclinical atrial fibrillation (SCAF) defined as device‐detected AF without symptoms. We comprehensively searched PubMed, Embase, and ClinicalTrials.gov. Studies comparing contemporary single‐ and dual‐chamber ICD (VVI‐/DDD‐ICD) versus VDD‐ICD were included. Restricted maximum likelihood method for random effect model and Mantel‐Haenszel method for fixed effect model were used to estimate the effect size of new‐onset AHREs, or SCAF detection in each group. Three prospective studies were identified and total of 991 participants were included. There were 330 (33.3%) in VDD‐ICD and 661 (66.7%) in VVI‐/DDD‐ICD. Most (78%) participants were men. Median follow‐up was from 365 days to 847 days. VDD‐ICD has a higher likelihood of detecting AHREs or SCAF as compared to VVI‐/DDD‐ICD [(OR random effect : 2.6; 95% CI: 1.2, 5.8; p = .018); I‐squared = 67.8%, p = .019]. This difference was more apparently seen in the comparison between VDD‐ICD and VVI‐ICD [(OR random effect: 3.8; 95% CI: 2.1, 6.6, p < .001), I‐squared = 0.0%, p = .518]. The result is same as fixed effect. Rate of AHREs detection observed in VDD‐ICD was not statistically different when compared to the only group with DDD‐ICD from SENSE trial. In conclusion, this meta‐analysis reveals that the use of floating atrial sensing dipole in VDD‐ICD increases the detection of new‐onset AHREs or SCAF when compared to VVI‐ICD, with similar atrial sensing performance to DDD‐ICD.

Detection and management of subclinical atrial fibrillation in implantable and wearable devices

This mini review lists available data on detection of subclinical atrial fibrillation (SCAF) in patients with cardiac implantable electronic devices and underlines uncertainties that remain when it comes to anticoagulation. Ongoing trials will examine the benefit of anticoagulation in these patients when SCAF duration is in the grey zone between 5–6 minutes and 24 hours. Meanwhile, smart and wearable devices may lead to a more patient-driven than physician-driven diagnostic in detection of AF. Wearables come with opportunities and challenges and cardiologists will need to focus on the right balance between using wearables as an additional diagnostic tool in patients at risk while avoiding overdiagnosis in the healthy general population.

Detection of subclinical atrial fibrillation after cryptogenic stroke using implantable cardiac monitors

BackgroundImplantable cardiac monitor (ICM) revealed subclinical atrial fibrillation (SCAF) in up to 30% of cryptogenic stroke (CS) patients in randomized trials. However, real world data are limited. ObjectivesWe investigated SCAF occurrence, treatments, clinical outcomes and predictors of SCAF in a multicenter real-world population subjected to ICM after CS. MethodsFrom September 2016 to November 2019, 20 Italian centers collected data of consecutive patients receiving ICM after CS and followed with remote and outpatient follow-up according to clinical practice. All device-detected AF events were confirmed by the cardiologist to diagnose SCAF. ResultsICM was implanted in 334 CS patients (mean age±SD 67.4±11.5 years, 129 (38.6%) females, 242 (76.1%) with CHA2DS2-VASC score≥4). During a follow-up of 23.6 (IQR 14.6-31.5) months, SCAF was diagnosed in 92 (27.5%) patients. First episode was asymptomatic in 81 (88.1%). SCAF daily burden ≥5 minutes was 22.0%, 24.1% and 31.5% at 6, 12, and 24 months after ICM implantation. Median time to first day with AF was 60 (IQR 18-140) days. Female gender, age>69 years, PR interval>160 ms and cortical-subcortical infarct type at enrolment were independently associated with an increased risk of SCAF. ConclusionsIn a real-world population, ICM detected SCAF in more than a quarter of CS patients. This experience confirms the relevance of implanting CS patients, for maximizing the possibilities to detect AF, following failure of Holter monitoring, according to guidelines. However, there is need to demonstrate that shift to oral anticoagulation following SCAF detection is associated with reduced risk of recurrent stroke.

Detection of Subclinical Atrial Fibrillation After Stroke

Detection of Subclinical Atrial Fibrillation After Stroke

Usefulness of P Wave Duration in Embolic Stroke of Undetermined Source.

The investigation of the potential association between ischemic stroke and subclinical atrial fibrillation (SCAF) is important for secondary prevention. We aimed to determine whether SCAF can be predicted by atrial substrate measurement with P wave signal-averaged electrocardiography (SAECG). We recruited 125 consecutive patients with embolic stroke of undetermined source (ESUS) and 125 patients with paroxysmal atrial fibrillation as controls. All participants underwent P wave SAECG at baseline, and patients with ESUS were followed up with Holter monitoring and electrocardiography at baseline, 3, 6, and 12 months after discharge and every 6 months thereafter. In the ESUS group, 32 (25.6%) patients were diagnosed with SCAF during follow-up. There were no significant differences between the groups regarding atrial substrate. P wave duration (PWD) was a significant predictor of SCAF. Stroke recurrence occurred in 22 patients (17.6%), and prolonged PWD (≥ 135 ms) predicted stroke recurrence more robustly than SCAF detection. In ESUS patients, PWD can be a useful biomarker to predict SCAF and to identify patients who are more likely to have a recurrent embolic stroke associated with an atrial cardiopathy. Further research is needed for supporting the utility and applicability of PWD.

Subclinical and Device-Detected Atrial Fibrillation: Pondering the Knowledge Gap: A Scientific Statement From the American Heart Association.

The widespread use of cardiac implantable electronic devices and wearable monitors has led to the detection of subclinical atrial fibrillation in a substantial proportion of patients. There is evidence that these asymptomatic arrhythmias are associated with increased risk of stroke. Thus, detection of subclinical atrial fibrillation may offer an opportunity to reduce stroke risk by initiating anticoagulation. However, it is unknown whether long-term anticoagulation is warranted and in what populations. This scientific statement explores the existing data on the prevalence, clinical significance, and management of subclinical atrial fibrillation and identifies current gaps in knowledge and areas of controversy and consensus.

On the Effectiveness of Deep Representation Learning: the Atrial Fibrillation Case.

The automatic and unsupervised analysis of biomedical time series is of primary importance for diagnostic and preventive medicine, enabling fast and reliable data processing to reveal clinical insights without the need for human intervention. Representation learning (RL) methods perform an automatic extraction of meaningful features that can be used, e.g., for a subsequent classification of the measured data. The goal of this study is to explore and quantify the benefits of RL techniques of varying degrees of complexity, focusing on modern deep learning (DL) architectures. We focus on the automatic classification of atrial fibrillation (AF) events from noisy single-lead electrocardiographic signals (ECG) obtained from wireless sensors. This is an important task as it allows the detection of sub-clinical AF which is hard to diagnose with a short in-clinic 12-lead ECG. The effectiveness of the considered architectures is quantified and discussed in terms of classification performance, memory/data efficiency and computational complexity.

P5350Atrial fibrillation prediction using P wave signal-averaged ECG in patients with embolic stroke of undetermined source

Abstract Background Approximately 10–25% of ischemic strokes are of unknown origin. Determining their potential association with subclinical atrial fibrillation (SCAF) is important for proper secondary prevention. We investigated whether SCAF can be predicted by assessing the atrial substrate with signal-averaged electrocardiography (SAECG). Methods Between April 2015 and February 2018, we recruited 125 consecutive patients with embolic stroke of undetermined source (ESUS) and 125 patients with paroxysmal atrial fibrillation (AF) patients as control. All participants underwent P wave SAECG at baseline and ESUS patients were followed up with ECG and Holter ECG, at baseline, 3, 6, and 12 months after discharge, and every 12 months thereafter. Results In the ESUS group (69 males, 68.4±12.1 years), 32 (25.6%) patients were diagnosed with SCAF during follow-up. There were no significant differences between both groups in terms of P wave duration [PWD] (ESUS vs. AF, P=0.321). PWD demonstrated a significant predictive efficacy for SCAF detection during follow-up (C-index of standard PWD=0.657, 95% confidence interval (CI) 0.552–0.761, P=0.008). Stroke recurrence occurred in 22 patients (17.6%) and was significantly associated with PWD but not SCAF (odds ratio 2.756, 95% CI 1.061–7.161, P=0.037). Conclusion PWD, an ECG biomarker associated with atrial substrate directly contributes to AF and ESUS, is useful for predicting SCAF. The potential for using this simple ECG biomarker for screening for SCAF amongst ESUS patients merits further exploration.

Abstract MP16: Incremental Diagnostic Yield of 4 Weeks versus 2 Weeks of Ambulatory Heart Rhythm Monitoring for the Detection of Subclinical Atrial Fibrillation: The Atherosclerosis Risk in Communities (ARIC) Study

Introduction: Subclinical atrial fibrillation (AF) has been associated with greater stroke risk; however, subclinical AF can be intermittent, and hence hard to detect. Little is known about the diagnostic yield of extending electrocardiogram (ECG) monitoring beyond 2 weeks on subclinical AF detection, particularly among individuals without a clinical indication. Hypothesis: Extending ECG monitoring from 2 weeks to 4 weeks will increase detection of AF Methods: We included ARIC study participants who attended visit 6 (2016-2017), without a history of AF, and who wore a leadless, ambulatory ECG monitor (Zio® XT Patch by iRhythm Technologies Inc.) twice, each time for up to a maximum of 2 weeks. AF history was based on ARIC ascertainment (hospitalization codes through 2016, ECGs at prior ARIC visits 1-5) or self-reported AF at visit 6. AF on the Zio® XT Patch was defined as an irregularly irregular rhythm with absent P-waves lasting ≥30 seconds. Results: We included 387 ARIC participants (mean ± SD aged 79 ± 4 years, 54% female, 11% non-white race). Mean recording time was 13.3 ± 1.7 days for the first Ziopatch, 13.1 ± 2.0 for the second patch, and 26.4 ± 2.9 for the combined 4 weeks. Based on ≤2 weeks of monitoring, the prevalence of subclinical AF was 2.6% (95% CI: 1.0-4.2%; n=10); this increased to 4.4% (95% CI: 2.4-6.4%; n=17) with ≤4 weeks of monitoring. Thus, the incremental diagnostic yield of 4 weeks versus 2 weeks of monitoring was 70% (95% CI: 41.6-98.4%). The mean time to first AF episode was 10.5 ± 8.0 days with a median of 13.4 days (IQR=2.0-19.7). Cumulative yield of AF detection over the monitoring time is shown in the Figure . Conclusions: Among elderly community-dwelling individuals, extending ECG monitoring from 2 weeks to 4 weeks increased detection of AF. These findings help inform the debate on ECG screening for subclinical AF; however, more research is needed to define the optimal duration of ECG monitoring time.