Device-detected Atrial Fibrillation Research Articles

Anticoagulation in device-detected atrial fibrillation with or without vascular disease: a combined analysis of the NOAH-AFNET 6 and ARTESiA trials.

The optimal antithrombotic therapy in patients with device-detected atrial fibrillation (DDAF) is unknown. Concomitant vascular disease can modify the benefits and risks of anticoagulation. These pre-specified analyses of the NOAH-AFNET 6 (n=2534 patients) and ARTESiA (n=4012 patients) trials compared anticoagulation to no anticoagulation in patients with DDAF with or without vascular disease, defined as prior stroke/transient ischemic attack, coronary or peripheral artery disease. Efficacy outcomes were the primary outcomes of both trials, a composite of stroke, systemic arterial embolism (SE), myocardial infarction, pulmonary embolism or cardiovascular death, and stroke or SE. Safety outcomes were major bleeding or major bleeding and death. In patients with vascular disease (NOAH-AFNET 6 56%, ARTESiA 46.0%), stroke, myocardial infarction, systemic or pulmonary embolism, or cardiovascular death occurred at 3.9%/patient-year with and 5.0%/patient-year without anticoagulation (NOAH-AFNET 6), and 3.2%/patient-year with and 4.4%/patient-year without anticoagulation (ARTESiA). Without vascular disease, outcomes were equal with and without anticoagulation (NOAH-AFNET 6 2.7%/patient-year, ARTESiA 2.3%/patient-year in both randomised groups). Meta-analysis found consistent results across both trials (I2heterogeneity=6%) with a trend for interaction with randomised therapy (pinteraction=0.08). Stroke/SE behaved similarly. Anticoagulation increased major bleeding in vascular disease patients (edoxaban 2.1%/patient-year, no anticoagulation 1.3%/patient-year; apixaban 1.7%/patient-year; no anticoagulation 1.1%/patient-year; incidence rate ratio 1.55 [1.10-2.20]) and without vascular disease (edoxaban 2.2%/patient-year; no anticoagulation 0.6%/patient-year; apixaban 1.4%/patient-year; no anticoagulation 1.1%/patient-year, incidence rate ratio 1.93 [0.72-5.20]). Patients with DDAF and vascular disease are at higher risk of stroke and cardiovascular events and may derive a greater benefit from anticoagulation than patients with DDAF without vascular disease.

The incidence of atrial fibrillation detected by implantable loop recorders: a comparison between patients with and without embolic stroke of undetermined source.

Stroke is the most debilitating outcome of atrial fibrillation (AF). The use of implantable loop recorders increases the detection of AF episodes among patients with embolic stroke of undetermined source. The significance of device-detected AF, or subclinical AF, is unknown. This study aimed to compare the incidence of AF detected by implantable loop recorder in patients with and without embolic stroke of undetermined source. We retrospectively studied all patients without known AF who were referred to our institution for implantable loop recorder implantation following embolic stroke of undetermined source, syncope, or palpitations from March 2009 to November 2019. The primary endpoint was any detection of AF or atrial flutter by implantable loop recorder. Seven hundred and fifty patients were included and followed up for a mean duration of 731 days (SD 443). An implantable loop recorder was implanted following embolic stroke of undetermined source in 323 and for assessment of syncope, palpitations, or another reason in 427 patients. The incidence of AF was significantly (P < 0.001) higher among patients with embolic stroke of undetermined source compared with the non-embolic stroke of undetermined source group; 48.6% vs. 13.8% (for any duration of AF) and 32.2% vs. 12.4% (for AF lasting ≥30 s) both P < 0.001. Kaplan-Meier analysis showed significantly higher incidence of AF for incremental durations of AF up to >5.5 h, but not >24 h. This was driven by longest AF durations of <6 min and between 5.5 h and 24 h, suggesting a bimodal distribution. In a multivariable Cox regression analysis, embolic stroke of undetermined source independently conferred an almost 5-fold increase in the hazard for any duration of AF. The incidence of AF is significantly higher amongst embolic stroke of undetermined source vs. non-embolic stroke of undetermined source patients monitored constantly by an implantable loop recorder. A high number of embolic stroke of undetermined source survivors have short-duration AF episodes. Further work is needed to determine the optimal treatment strategy of these AF episodes in embolic stroke of undetermined source.

Atrial fibrillation burden: a new outcome predictor and therapeutic target.

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is not a dichotomous disease trait. Technological innovations enable long-term rhythm monitoring in many patients and can estimate AF burden. These technologies are already used to detect and monitor AF. This review describes the relation between AF burden and outcomes and potential effects of AF burden reduction. A lower AF burden is associated with a lower risk of stroke and heart failure in patients with AF: stroke risk without anticoagulation is lower in patients with device-detected AF and a low AF burden (stroke rate 1%/year) than in patients with persistent and permanent AF (stroke rate 3%/year). Paroxysmal AF shows intermediate stroke rates (2%/year). Atrial fibrillation burden-reducing interventions can reduce cardiovascular outcomes in patients with AF: early rhythm control reduces cardiovascular events including stroke and heart failure in patients with recently diagnosed AF and cardiovascular conditions. In patients with heart failure and AF, early rhythm control and AF ablation, interventions that reduce AF burden, reduce mortality and heart failure events. Recent technological innovations allow to estimate AF burden in clinical care, creating opportunities and challenges. While evidence remains limited, the existing data already suggest that AF burden reduction could be a therapeutic goal. In addition to anticoagulation and treatment of cardiovascular conditions, AF burden reduction emerges as a therapeutic goal. Future research will define the AF burden that constitutes a relevant risk of stroke and heart failure. Technologies quantifying AF burden need careful validation to advance the field.

Direct oral anticoagulants for stroke prevention in patients with device-detected atrial fibrillation: assessing net clinical benefit.

Subclinical, device-detected atrial fibrillation (AF) is frequently recorded by pacemakers and other implanted cardiac rhythm devices. Patients with device-detected AF have an elevated risk of stroke, but a lower risk of stroke than similar patients with clinical AF captured with surface electrocardiogram. Two randomized clinical trials (NOAH-AFNET 6 and ARTESiA) have tested a direct oral anticoagulant (DOAC) against aspirin or placebo. A study-level meta-analysis of the two trials found that treatment with a DOAC resulted in a 32% reduction in ischaemic stroke and a 62% increase in major bleeding; the results of the two trials were consistent. The annualized rate of stroke in the control arms was ∼1%. Several factors point towards overall net benefit from DOAC treatment for patients with device-detected AF. Strokes in ARTESiA were frequently fatal or disabling and bleeds were rarely lethal. The higher absolute rates of major bleeding compared with ischaemic stroke while on treatment with a DOAC in the two trials are consistent with the ratio of bleeds to strokes seen in the pivotal DOAC vs. warfarin trials in patients with clinical AF. Prior research has concluded that patients place a higher emphasis on stroke prevention than on bleeding. Further research is needed to identify the characteristics that will help identify patients with device-detected AF who will receive the greatest benefit from DOAC treatment.

Predictors of paroxysmal atrial fibrillation in patients with a cryptogenic stroke: Selecting patients for long-term rhythm monitoring

BackgroundAfter a cryptogenic stroke, patients often will require prolonged cardiac monitoring; however, the subset of patients who would benefit from long-term rhythm monitoring is not clearly defined. ObjectiveThe purpose of this study was to create a risk score by identifying significant predictors of atrial fibrillation (AF) using age, sex, comorbidities, baseline 12-lead electrocardiogram, short-term rhythm monitoring, and echocardiographic data and to compare it to previously published risk scores. MethodsPatients admitted to Montefiore Medical Center between May 2017 and June 2022 with a primary diagnosis of cryptogenic stroke or transient ischemic attack who underwent long-term rhythm monitoring with an implantable cardiac monitor were retrospectively analyzed. ResultsVariables positively associated with a diagnosis of clinically significant AF include age (P <.001), race (P = .022), diabetes status (P = .026), chronic obstructive pulmonary disease status (P = .012), presence of atrial runs (P = .003), number of atrial runs per 24 hours (P <.001), total number of atrial run beats per 24 hours (P <.001), number of beats in the longest atrial run (P <.001), left atrial enlargement (P = .007), and at least mild mitral regurgitation (P = .009). We created a risk stratification score for our population, termed the ACL score. The ACL score demonstrated superiority to the CHA2DS2-VASc score and comparability to the C2HEST score for predicting device-detected AF. ConclusionThe ACL score enables clinicians to better predict which patients are more likely to be diagnosed with device-Detected AF after a cryptogenic stroke.

In device-detected AF, DOACs vs. aspirin or placebo reduce ischemic stroke and increase major bleeding.

McIntyre WF, Benz AP, Becher N, et al. Direct oral anticoagulants for stroke prevention in patients with device-detected atrial fibrillation: a study-level meta-analysis of the NOAH-AFNET 6 and ARTESiA trials. Circulation. 2024;149:981-988. 37952187.

Time to benefit and harm of direct oral anticoagulants in device-detected atrial fibrillation: A pooled analysis of the NOAH-AFNET 6 and ARTESiA trials

BackgroundDirect oral anticoagulants (DOACs) reduce stroke risk in patients with device-detected atrial fibrillation (DD-AFib) but increase major bleeding risk. The time to benefit (TTB) and time to harm (TTH) are not well quantified. ObjectiveThe purpose of this study was to determine TTB and TTH in DOACs-treated patients with DD-AFib. MethodsStudies were identified from PubMed searching until November 2023. The primary efficacy outcome was the time to the first stroke event, and the primary safety outcome was the time to the first major bleeding event. Pooled hazard ratio (HR) and its confidence interval (CI) were calculated through reconstructed patient-level data and study-level data. Weibull model and Markov chain Monte Carlo simulation were applied to determine time to specific absolute risk change thresholds. ResultsTwo trials involving DOACs—NOAH-AFNET 6 (Non–vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes) and ARTESiA (Apixaban for the Reduction of Thrombo-Embolism in Patients With Device-Detected Sub-Clinical Atrial Fibrillation)—were identified, which randomized 6548 adults with a mean age of >75 years and a median atrial high-rate episode duration ranging from 1.5 to 2.8 hours. DOACs decreased the risk of stroke (HR 0.67; 95% CI 0.50–0.90) but increased the risk of major bleeding (HR 1.57; 95% CI 1.21–2.04). A TTB of 2.67 years was needed to prevent 1 stroke per 100 DOACs-treated patients, while a TTH of 1.67 years was needed to observe 1 major bleeding. ConclusionIn elderly patients with low durations of DD-AFib, DOACs result in a delayed and restricted stroke-preventive benefit while posing an early-onset bleeding risk. Our findings offer new insights into the risk-benefit profile and provide clinicians an additional dimension to facilitate shared decision-making discussions with patients.

Continuing evaluation of atrial fibrillation detection after cryptogenic stroke: one-year findings from a multi-center study with confirm Rx ICM

Abstract Background The detection of atrial fibrillation (AF) after a cryptogenic stroke (CS) carries crucial therapeutic implications. While clinical trials have meticulously explored the incidence of AF in CS patients, real-world data on this topic remain relatively sparse. In this study, we aimed to assess the incidence of AF among patients with cryptogenic stroke, who underwent the implantation of an insertable cardiac monitor (ICM). The abstract reports the interim results from the CS sub-study of the Smart Registry. Methods A prospective, single-arm, multi-center registry was conducted to identify AF in patients with cryptogenic stroke using the Confirm R ICM. Inclusion criteria comprised participants aged 40 years or older who had experienced cryptogenic strokes within a 90-day window. Prior to enrollment, comprehensive diagnostic assessments were performed to meticulously rule out all potential sources of embolism, in accordance with the minimal standards of the American and European Guidelines. At each follow-up visit, expert electrophysiologists reviewed and adjudicated ICM detected AF episodes. The primary endpoint was the cumulative incidence of true device-detected AF (lasting more than 30 seconds) at 6 months. Kaplan-Meier curves were employed to assess the cumulative incidence of true device-detected AF through 12 months. Results In our study, 117 patients were enrolled across 19 global sites from September 2021 to August 31, 2023. Kaplan-Meier analysis revealed a 21.3% probability (confidence interval (CI): 14.5%, 30.7%) of true AF episodes lasting more than 30 seconds at 6 months, increasing to 31.0% (CI: 22.0%, 42.5%) at 12 months. Similar results were observed in episodes lasting over 120 seconds at both 6 months (20.7%) and 12 months (30.5%). In average, 14.4 true AF episodes per patient were detected per year. The median time from implantation to AF detection (&amp;gt; 30 seconds) was 31.5 days (interquartile range, 7 to 191). Conclusion Our ongoing study illustrates the effectiveness of the Confirm Rx ICM in detecting atrial fibrillation after cryptogenic stroke. These results confirm the diagnostics value of long-term continuous AF monitoring in cryptogenic stroke patients.

LB-469807-05 OUTCOMES WITH AND WITHOUT ORAL ANTICOAGULATION IN PATIENTS WITH PRIOR STROKE AND DEVICE-DETECTED ATRIAL FIBRILLATION: THE NOAH-AFNET 6 TRIAL

LB-469807-05 OUTCOMES WITH AND WITHOUT ORAL ANTICOAGULATION IN PATIENTS WITH PRIOR STROKE AND DEVICE-DETECTED ATRIAL FIBRILLATION: THE NOAH-AFNET 6 TRIAL

Cardiology: What You May Have Missed in 2023.

Cardiology and all its subspecialties continue to push the envelope in developing new treatment strategies for a wide variety of diseases. After screening more than 1300 articles, we highlight a selection of important cardiology articles published in 2023. Starting with prevention, we note articles that look at the effect of semaglutide in patients with obesity as well as a first-in-class drug, bempedoic acid, on cardiovascular outcomes. We have also examined new evidence comparing conservative management with invasive management of frail, older patients with non-ST-segment elevation myocardial infarction (NSTEMI). In patients with cardiac arrest secondary to NSTEMI, another article examines the rationale for expedited transfer to a cardiac arrest center. The STREAM-2 (Strategic Reperfusion in Elderly Patients Early After Myocardial Infarction) trial builds on looking at half-dose thrombolysis in older populations with STEMI. Emphasis is placed on guideline-directed medical therapy before hospital discharge in those with heart failure. In addition, in patients with stable symptomatic coronary artery disease, initial noninvasive testing using coronary computed tomography angiography may be a viable option compared with invasive strategies. More details have emerged on anticoagulation strategies in those with device-detected atrial fibrillation. Finally, transcatheter approaches to treat both mitral and tricuspid regurgitation have also been included.

Oral anticoagulation in device-detected atrial fibrillation: effects of age, sex, cardiovascular comorbidities, and kidney function on outcomes in the NOAH-AFNET 6 trial.

Oral anticoagulation in device-detected atrial fibrillation: effects of age, sex, cardiovascular comorbidities, and kidney function on outcomes in the NOAH-AFNET 6 trial.

Toward More Personalized Management of Device-Detected Atrial Fibrillation

This Viewpoint discusses the need to individualize the management of subclinical atrial fibrillation according to burden (among other factors) by modeling stroke risk.

Longer and better lives for patients with atrial fibrillation: the 9th AFNET/EHRA consensus conference.

Recent trial data demonstrate beneficial effects of active rhythm management in patients with atrial fibrillation (AF) and support the concept that a low arrhythmia burden is associated with a low risk of AF-related complications. The aim of this document is to summarize the key outcomes of the 9th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA). Eighty-three international experts met in Münster for 2 days in September 2023. Key findings are as follows: (i) Active rhythm management should be part of the default initial treatment for all suitable patients with AF. (ii) Patients with device-detected AF have a low burden of AF and a low risk of stroke. Anticoagulation prevents some strokes and also increases major but non-lethal bleeding. (iii) More research is needed to improve stroke risk prediction in patients with AF, especially in those with a low AF burden. Biomolecules, genetics, and imaging can support this. (iv) The presence of AF should trigger systematic workup and comprehensive treatment of concomitant cardiovascular conditions. (v) Machine learning algorithms have been used to improve detection or likely development of AF. Cooperation between clinicians and data scientists is needed to leverage the potential of data science applications for patients with AF. Patients with AF and a low arrhythmia burden have a lower risk of stroke and other cardiovascular events than those with a high arrhythmia burden. Combining active rhythm control, anticoagulation, rate control, and therapy of concomitant cardiovascular conditions can improve the lives of patients with AF.

Clinical Predictors of Device-Detected Atrial Fibrillation During 2.5 Years After Cardiac Surgery: Prospective RACE V Cohort

BackgroundPostoperative atrial fibrillation (POAF) is a frequent complication after cardiac surgery that is associated with late atrial fibrillation (AF) recurrences (late-POAF) and increased morbidity and long-term mortality. ObjectivesThis study sought to determine device-detected POAF incidence and to identify clinical variables associated with POAF, both in patients with and without preoperative AF history. MethodsA total of 133 consecutive patients undergoing cardiac surgery were prospectively enrolled and continuously monitored with an implantable loop recorder for 2.5 years after surgery. Preoperative transthoracic echocardiography, 12-lead electrocardiogram, blood biomarkers, and clinical data were analyzed to develop prediction models for early- and late-POAF. ResultsIn patients without preoperative AF history, early-POAF within the first 90 postoperative days occurred in 41 (47.1%) of 87 patients. Late-POAF after the first 90 postoperative days occurred in 22 (25%) of 87 patients, and 20 of these patients also had early-POAF during the first 90 days (20 of 22 [91%]). Increased right atrial minimum volume indexed for body surface area (RAVImin) and early-POAF were independently associated with late-POAF. A prediction model for late-POAF, which included RAVImin >11 mL/m2, age >65 years, and early-POAF, achieved an area under the curve of 0.82 (95% CI: 0.72-0.92). For patients with preoperative AF-history, late-POAF recurrences were frequent (22 of 33 [67%]). Increased RAVImin was independently associated with a higher incidence of late-POAF. ConclusionsIn patients with and without AF history, late-POAF recurrences are frequent, including in patients undergoing surgical AF ablation. In patients with no history of AF, late-POAF might be predicted with excellent accuracy by using a combination of preoperative variables. In patients with a history of AF, signs of advanced AF substrate (eg, increased right atrial volumes) were associated with long-term AF recurrences. [Reappraisal of Atrial Fibrillation: Interaction Between Hypercoagulability, Electrical Remodeling, and Vascular Destabilisation in the Progression of AF; NCT03124576]

Oral factor Xa inhibitors for stroke prevention in patients with device-detected atrial fibrillation : Recent evidence from the NOAH-AFNET 6 and ARTESiA trials

Oral factor Xa inhibitors for stroke prevention in patients with device-detected atrial fibrillation : Recent evidence from the NOAH-AFNET 6 and ARTESiA trials

Atrial Fibrillation Detection and Load: Knowledge Gaps Related to Stroke Prevention.

Atrial fibrillation is a major cause of ischemic stroke. Technological advances now support prolonged cardiac rhythm monitoring using either surface electrodes or insertable cardiac monitors. Four major randomized controlled trials show that prolonged cardiac monitoring detects subclinical paroxysmal atrial fibrillation in 9% to 16% of patients with ischemic stroke, including in patients with potential alternative causes such as large artery disease or small vessel occlusion; however, the optimal monitoring strategy, including the target patient population and the monitoring device (whether to use an event monitor, insertable cardiac monitor, or stepped approach) has not been well defined. Furthermore, the clinical significance of very short duration paroxysmal atrial fibrillation remains controversial. The relevance of the duration of monitoring, burden of device-detected atrial fibrillation, and its proximity to the acute ischemic stroke will require more research to define the most effective methods for stroke prevention in this patient population.

Incidence and delays of a new clinical atrial fibrillation diagnosis following an atrial fibrillation detection signal on a personal electrocardiogram device available to consumers

Abstract Background Patient and consumer-led detection of atrial fibrillation (AF) using medical devices available to consumers such as personal electrocardiogram (ECG) devices is becoming increasingly common. However, the AF patient journey after an AF signal observed on the personal ECG device is variable and poorly defined. Purpose To report the incidence and temporality of a new clinical AF diagnosis among individuals with a device-detected AF signal. Methods This retrospective cohort study was conducted using the OMNY Health open-source claims database linked to data recorded from a medical grade, United States Food and Drug Administration (FDA)-cleared, personal ECG device available to consumers. Adults (≥18 years) with ≥1 device-detected AF signal were selected between July 1, 2017, and December 31, 2020. The date of the first device-detected AF signal was defined as the "index date." Individuals were required to have continuous healthcare activity for 12 months before (baseline period) and 12 months after (follow-up period) the index date, and ≥2 device recordings (of AF or not) during a 12-month follow-up period. Individuals with a history of AF diagnosis in the baseline period were excluded. Outcomes evaluated during follow-up included: 1) New clinical AF diagnosis (defined as ≥1 non-diagnostic medical claim with an AF diagnosis [ICD-10 I48.0-I48.2, I48.91] in any position); 2) Time from index date to new clinical AF diagnosis; and 3) Number of device-detected AF signals. Results The study included 32,484 individuals with ≥1 device-detected AF signal (mean 11.8, SD: 23.7 signals). Mean age was 68.7 (SD: 11.9) years; 71.4% were 65 years or older; and 43.1% were female. The mean baseline CHA2DS2-VASc risk score was 2.0 (SD: 1.3). Overall, about a quarter (24.1%; n=7,822) of individuals had a new clinical AF diagnosis within 1 year of index date (Figure 1). The likelihood of a new clinical AF diagnosis was lower for younger age groups (age 18-44 = 8.0%; age 45-54 = 16.6%; age 55-64 = 23.0%; age 65-74 = 26.1%; age 75+: 26.2%) (Figure 2), and individuals with certain CHA2DS2-VASc risk factors (congestive heart failure: 26.4%; hypertension: 26.3%) had a slightly higher likelihood of a new clinical AF diagnosis than the overall population. In those with a new AF diagnosis, this was delayed until after 90 days from the index date in 46.7% of the patients (Figure 1). Conclusions This observational study offers unique real-world insights into the use of personal ECG devices and their potential ability to lead to clinician-diagnosed AF. Only a quarter of patients had a new clinical AF diagnosis within a year of their first device-detected AF signal, and diagnosis was delayed by &amp;gt;90 days in almost half of cases. This may relate to false positives of the device AF diagnosis, and/or poorly defined AF pathway for patient- or consumer-led AF detection.

Serotonin antidepressants and atrial fibrillation burden from cardiac implantable electronic devices.

Depression and anxiety show a bidirectional relationship with atrial fibrillation (AF). Antidepressant use is associated with a reduction in the incidence of AF. However, no studies have examined the relationship between antidepressant use and AF burden (time in AF). This retrospective cohort study examined cardiac implantable device-detected AF episodes and their relationship with antidepressant use, among other treatment factors. Consecutive patients from the Western Health Cardiology Department attending pacemaker checks between 2015 and 2021 were included. Patients with permanent AF were excluded, yielding 285 patients with no or paroxysmal AF, with a total of 772 patient encounters. Generalized estimating equations were used to model two processes: binary AF (present/absent) and the number of days in AF for patients with AF. Each yearly increase with age was associated with an increase in the odds of developing AF (OR 1.03 [1.00-1.05], p = .027). Male gender conferred a reduction in AF incidence (OR 0.30 [0.13-0.68], p = .004). Digoxin use was associated with incident AF (OR 4.43 [1.07-18.4], p = .04). Sotalol and heart-failure beta blocker use were associated with a decrease in AF burden (IRR 0.30 [0.12-0.78], p = .013 and 0.33 [0.14-0.81], p = .015). Selective serotonin reuptake inhibitor antidepressant use was associated with reduced AF burden (IRR 0.27 [0.09-0.81], p = .019), as was selective serotonin/noradrenaline reuptake inhibitor use (IRR 0.07 [0.03-0.15], p < .001). Older age, female gender and digoxin are associated with a higher odds of developing incident AF. Sotalol, heart failure beta blockers and serotonin-based antidepressants are associated with reduced AF burden. Further prospective study into the effects of antidepressants on atrial arrhythmias is warranted.

Design and Implementation of an Atrial Fibrillation Detection Algorithm on the ARM Cortex-M4 Microcontroller.

At present, a medium-level microcontroller is capable of performing edge computing and can handle the computation of neural network kernel functions. This makes it possible to implement a complete end-to-end solution incorporating signal acquisition, digital signal processing, and machine learning for the classification of cardiac arrhythmias on a small wearable device. In this work, we describe the design and implementation of several classifiers for atrial fibrillation detection on a general-purpose ARM Cortex-M4 microcontroller. We used the CMSIS-DSP library, which supports Naïve Bayes and Support Vector Machine classifiers, with different kernel functions. We also developed Python scripts to automatically transfer the Python model (trained in Scikit-learn) to the C environment. To train and evaluate the models, we used part of the data from the PhysioNet/Computing in Cardiology Challenge 2020 and performed simple classification of atrial fibrillation based on heart-rate irregularity. The performance of the classifiers was tested on a general-purpose ARM Cortex-M4 microcontroller (STM32WB55RG). Our study reveals that among the tested classifiers, the SVM classifier with RBF kernel function achieves the highest accuracy of 96.9%, sensitivity of 98.4%, and specificity of 95.8%. The execution time of this classifier was 720 μs per recording. We also discuss the advantages of moving computing tasks to edge devices, including increased power efficiency of the system, improved patient data privacy and security, and reduced overall system operation costs. In addition, we highlight a problem with false-positive detection and unclear significance of device-detected atrial fibrillation.

Device-detected atrial fibrillation in a large remote-monitored cohort: implications for anticoagulation and need for new pathways of service delivery

BackgroundRemote monitoring (RM) can facilitate early detection of subclinical and symptomatic atrial fibrillation (AF), providing an opportunity to evaluate the need for stroke prevention therapies. We aimed to characterize the burden of RM AF alerts and its impact on anticoagulation of patients with device-detected AF.MethodsConsecutive patients with a cardiac implantable electronic device, at least one AF episode, undergoing RM were included and assigned an estimated minimum CHA2DS2-VASc score based on age and device type. RM was provided via automated software system, providing rapid alert processing by device specialists and systematic, recurrent prompts for anticoagulation.ResultsFrom 7651 individual, 389,188 AF episodes were identified, 3120 (40.8%) permanent pacemakers, 2260 (29.5%) implantable loop recorders (ILRs), 987 (12.9%) implantable cardioverter defibrillators, 968 (12.7%) cardiac resynchronization therapy (CRT) defibrillators, and 316 (4.1%) CRT pacemakers. ILRs transmitted 48.8% of all AF episodes. At twelve-months, 3404 (44.5%) AF < 6 min, 1367 (17.9%) 6 min–6 h, 1206 (15.8%) 6–24 h, and 1674 (21.9%) ≥ 24 h. A minimum CHA2DS2-VASc score of 2 was assigned to 1704 (63.1%) of the patients with an AF episode of ≥ 6 h, 531 (31.2%) who were not anticoagulated at 12-months, and 1031 (61.6%) patients with an AF episode duration of ≥ 24 h, 290 (28.1%) were not anticoagulated.ConclusionsDespite being intensively managed via RM software system incorporating cues for anticoagulation, a substantial proportion of patients with increased stroke risk remained unanticoagulated after a device-detected AF episode of significant duration. These data highlight the need for improved clinical response pathways and an integrated care approach to RM.Trial registrationAustralian New Zealand Clinical Trial Registry: ACTRN12620001232921.Graphical