Atrial Fibrillation Monitoring Research Articles

Abstract 11773: Impact of Race on Incident Atrial Fibrillation in a Large Cohort With Cardiac Implantable Electronic Devices

Introduction: Prior studies showed lower rates of atrial fibrillation (AF) in African Americans (AA) compared to Caucasians (CC) despite a higher prevalence of AF risk factors. These studies often relied on a clinical diagnosis of AF or limited analyses to Medicare beneficiaries which may bias the results. Our objective is to compare AF-free survival in AA vs CC patients with dual chamber cardiac implantable electronic devices (CIEDs) capable of continuous AF monitoring. Hypothesis: There is no significant difference in incident AF between AA and CC patients with dual chamber CIEDs. Methods: Using the Optum® de-identified Electronic Health Record dataset (01/2007 to 06/2019) linked with the Medtronic CareLink® device database, we identified self-described AA and CC patients with dual chamber CIEDs and no prior AF history. The primary endpoint was time to first AF ≥ 6 minutes. Cox proportional hazards models were used to examine the association between race and AF while adjusting for age, sex, and vascular risk factors in the pacemaker and ICD cohorts. Results: Of the 110,323 patients analyzed, mean age was 69±13 years, 64% were male, 8.9% were AA, and 39% had a pacemaker. CC were older (69.5 vs 63.4 years) and more were male (65% vs 54%). Heart failure, hypertension and diabetes were more common in AA (36% vs 22%; 60% vs 47%; 32% vs 22%, respectively). Over a mean follow-up of 2.3±1.8 years, unadjusted AF-free survival was higher in AA compared to CC in both CIED cohorts (p<0.0001). After adjusting for age, sex and vascular risk factors, CC with pacemakers had a higher risk of incident AF (HR 1.10; 95% CI 1.03-1.17) but a lower risk was observed in CC with ICDs (HR 0.91; 95% CI 0.87-0.94) (Figure 1). Conclusions: In contrast to previous studies, this analysis of 110,323 CIED patients showed that adjusted AF-free survival was higher in AAs with pacemakers but not ICDs. These results challenge our understanding of the interaction between race and incident AF.

Impact of Atrial Fibrillation on Cardiovascular and Economic Outcomes in Patients with Chronic Lymphocytic Leukemia

Introduction: Chronic lymphocytic leukemia (CLL) is the most frequently diagnosed hematologic cancer, with many patients diagnosed at a later stage in life and typically with comorbidities that often complicate CLL management. Atrial fibrillation (AF) is the most common arrhythmia in the United States and is associated with high hospitalization and mortality rates. While the relationship between CLL and AF has been reported, there is limited real-world evidence on the clinical and economic impact of AF in CLL patients. The objectives of this study were to examine the impact of AF on cardiovascular (stroke, bleeding events, heart failure) and economic (costs and healthcare resource utilization [HRU]) outcomes among patients with CLL.Methods: This retrospective observational study used the IBM MarketScan Research Databases in Treatment Pathways that includes at least a 10-million sample of the commercial and Medicare supplemental claims database. Patients who were at least 18 years, diagnosed with CLL (identified by ICD-9/ICD-10) and continuously enrolled from January 2009 to July 2020 were included. CLL patients were followed up for one year after their first CLL diagnosis date to examine the incidence of AF. Cardiovascular outcomes were evaluated as the incidence of stroke, bleeding events, and heart failure among the CLL patients with and without AF. Costs and HRU were assessed following up until 1 year after the first date of AF, stroke, bleeding events, and heart failure. HRU was evaluated for outpatient, emergency room (ER), inpatient, and pharmacy visits, and by length of stay (LOS) for hospitalizations. Costs were evaluated in overall population and by HRU type. Statistical differences in clinical outcomes between patients with and without AF were compared using chi-square tests. The Mann Whitney Wilcoxon test was used to compare the medians for the HRU and cost outcomes. The associations between AF and hospitalizations as well as costs were evaluated by multivariable logistic regression and generalized linear model, respectively. Statistical significance was determined at a P-value of less than 0.05.Results: Among the total of 23,756 newly diagnosed CLL patients (median age 68 years, 57.83% male) included in the study, 11% had AF within 1 year of the CLL diagnosis. CLL patients who had AF were significantly older (median age: 67 vs 82 years) and had more male patients (56.9% vs 65.1%) compared to CLL patients without AF. Significantly higher rates of stroke (12.67% vs. 4.97%), bleeding events (17.45% vs. 8.53%), and heart failure (31.14% vs. 4.70%) were observed in CLL patients with AF than those without (Figure 1). Compared to the CLL cohort without AF, adjusted regression analysis indicated that overall, CLL cohort with AF was twice as likely to be hospitalized (odds ratio [OR]=2.03) and incurred 44% higher total costs (cost ratio [CR]=1.44). Further examining the impact of AF-related cardiovascular outcomes, we observed that CLL patients with AF who developed stroke, bleeding events, and heart failure had statistically significant higher HRU (outpatient, ER, inpatient, and pharmacy visits), longer LOS, and costs (total, outpatient, pharmacy) than CLL patients without AF. After adjusting for demographic and clinical confounders, significantly higher hospitalization rates and costs were also reported in the CLL cohort who had AF with further stroke (OR=2.59; CR=1.36), bleeding events (OR=3.27; CR=2.03), and heart failure (OR=5.47; CR=2.07) compared to the CLL cohort without AF.Conclusions: The findings of this real-world study demonstrated significantly higher hospitalizations, cardiovascular events, and economic burden incurred by CLL patients who had AF than those without. The presence of stroke, bleeding events, heart failure among CLL patients with AF further increased the HRU and costs. This study highlighted the importance of better disease management, more intentional monitoring for AF and improved CLL therapeutics with a lower risk of AF or cardiovascular toxicity to prevent or minimize the incidence of AF in CLL patients. [Display omitted] DisclosuresMohan: BeiGene, Ltd.: Current Employment. Yang: BeiGene, Ltd.: Current Employment. Liu: BeiGene, Ltd.: Current Employment. Dick: IBM Watson Health: Current Employment. Tang: BeiGene, Ltd.: Current Employment. Chanan-Khan: Ascentage: Research Funding; Alpha2 Pharmaceuticals, NonoDev, Starton: Current holder of stock options in a privately-held company; Cellectar: Current equity holder in publicly-traded company; Alpha2 Pharmaceuticals: Patents & Royalties: Tabi; Ascentage, Starton, Cellectar, NonoDev, Alpha2 Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; BeiGene, Jansen, Ascentage: Honoraria; BieGene, Jansen, Ascentage: Consultancy.

A novel single-lead handheld atrial fibrillation detection system

Objective. The single-lead handheld atrial fibrillation (AF) detection device is suitable for daily monitoring or early screening of AF in the hospital. However, the signal quality and the reliability of AF detection algorithm still need to be improved. This study proposed a novel AF detection system with a user-friendly interaction and a lightweight and accurate AF detection algorithm. Approach. The system consisted of a single-lead handheld electrocardiogram device with a novel appearance like a gaming handle and a smartphone terminal embedded with AF detection. After feature optimization, the rule-based multi-feature AF detection algorithm had relatively good AF detection ability. Three types of experiments were designed to test the performance of the system. (1) Test the accuracy and time/memory cost of the AF detection algorithm. (2) Compare the proposed device with the standard device Shimmer. (3) Use the simulator to test the effectiveness of the system. Main results. The percentage of differences of successive RR intervals larger than 50 ms (PNN50), minimum value of RR intervals (minRR), and coefficient of sample entropy (COSEn) were features chosen for AF detection. (1) The sensitivity, specificity, and accuracy were 96.00%, 99.75%, 97.88% on the MIT-BIH AF database, and 98.50%, 94.50%, 96.50% on the clinical database we founded. The time/memory cost of the proposed algorithm was much smaller than that of support vector machine. (2) The mean correlation coefficient of RR was 0.9950, indicating a high degree of consistency. (3) This system showed the effectiveness of AF detection. Significance. The proposed single-lead handheld AF detection system is demonstrated to be accurate, lightweight, consistent with the standard device, and efficient for AF detection.

Atrial fibrillation burden and cognitive decline in elderly patients undergoing continuous monitoring

To study the relationship between subclinical atrial fibrillation (AF) and changes in cognitive function in a large cohort of individuals with stroke risk factors. Individuals with no prior AF diagnosis but with risk factors for stroke were recruited to undergo annual cognitive assessment with the Montreal Cognitive Assessment (MoCA) along with implantable loop recorder (ILR) monitoring for AF for 3 years. If AF episodes lasting ≥6 minutes were detected, oral anticoagulation (OAC) treatment was initiated. A total of 1194 participants (55.2 % men, mean age 74.5 (±3.9)) had a combined duration of heart rhythm monitoring of ≈1.3 million days. Among these, 339 participants (28.3%) had adjudicated AF, with a median AF burden of 0.072% (0.02, 0.39), and 324 (96%) initiated OAC. When stratifying the participants into AF burden groups (No AF, AFlow (AF burden <0.25%), and AFhigh, (AF burden >0.25%)), only participants in the AFlow group had a decrease in MoCA score over time (P=.03), although this was not significant after adjustment for stroke risk factors. A subgroup analysis of 175 participants (14.6%) with a MoCA <26 at 3 years found no association to AF diagnosis or burden. In a high-risk population, subclinical AF detected by continuous monitoring and subsequently treated with OAC was not associated with a significant change in MoCA score over a 3-year period.

B-PO05-152 BASELINE CONDUCTION INTERVALS AND TRANS-ISTHMUS TIMING AND CORRELATION WITH ATRIAL FIBRILLATION

Prevalence of atrial fibrillation (AF) in patients with typical atrial flutter (tAFL) is. higher than in patients without tAFL. Correlation between right atrial conduction velocity measured during tAFL ablation and prevalence of AF has not been described. We evaluated whether baseline conduction intervals or atrial conduction velocity as measured by trans-isthmus timing during tAFL ablation is correlated with prevalence and incidence of AF. We performed a retrospective analysis of 43 patients that underwent tAFL ablation. We measured baseline conduction intervals and trans-isthmus timing after CTI block and analyzed whether this was correlated with prevalence of AF. Trans-isthmus time was measured as the conduction time from proximal CS pacing to the lateral border of the CTI ablation line. T-tests and fisher exact tests were run on all the variables. A total of 43 patients who had a CTI ablation were studied. The mean age was 64 years. 22 of the patients had AF at the time of the procedure. Of the baseline conduction intervals, shorter QT and RR times were significant for less prevalence of AF with a p-value of <0.05. Also, a shorter trans-isthmus timing correlated with a significantly lower prevalence of AF (p = 0.036). In patients undergoing tAFL ablation, a longer QT, RR, and trans-isthmus times may correlate with a higher prevalence of AF. This may help guide aggressiveness of AF monitoring in patients presenting for tAFL ablation. Further investigation is needed.

Smartwatch monitoring for atrial fibrillation after stroke—The Pulsewatch Study: Protocol for a multiphase randomized controlled trial

BackgroundAtrial fibrillation (AF) is a common heart rhythm disorder that elevates stroke risk. Stroke survivors undergo routine heart rhythm monitoring for AF. Smartwatches are capable of AF detection and potentially can replace traditional cardiac monitoring in stroke patients.ObjectiveThe goal of Pulsewatch is to assess the accuracy, usability, and adherence of a smartwatch-based AF detection system in stroke patients.MethodsThe study will consist of two parts. Part I will have 6 focus groups with stroke patients, caretakers, and physicians, and a Hack-a-thon, to inform development of the Pulsewatch system. Part II is a randomized clinical trial with 2 phases designed to assess the accuracy and usability in the first phase (14 days) and adherence in the second phase (30 days). Participants will be randomized in a 3:1 ratio (intervention to control) for the first phase, and both arms will receive gold-standard electrocardiographic (ECG) monitoring. The intervention group additionally will receive a smartphone/smartwatch dyad with the Pulsewatch applications. Upon completion of 14 days, participants will be re-randomized in a 1:1 ratio. The intervention group will receive the Pulsewatch system and a handheld ECG device, while the control group will be passively monitored. Participants will complete questionnaires at enrollment and at 14- and 44-day follow-up visits to assess various psychosocial measures and health behaviors.ResultsPart I was completed in August 2019. Enrollment for Part II began September 2019, with expected completion by the end of 2021.ConclusionPulsewatch aims to demonstrate that a smartwatch can be accurate for real-time AF detection, and that older stroke patients will find the system usable and will adhere to monitoring.

Reexamination of the Embolic Stroke of Undetermined Source Concept.

Occult atrial fibrillation (AF) is a leading cause of stroke of unclear cause. The optimal approach to secondary stroke prevention for these patients remains elusive. The term embolic stroke of undetermined source (ESUS) was coined to describe ischemic strokes in which the radiographic features demonstrate territorial infarcts resembling those seen in patients with confirmed sources of embolism but without a clear source of embolism detected. It was assumed that patients with ESUS had a high rate of occult AF and would benefit from treatment with direct oral anticoagulants, which are at least as effective as vitamin K antagonists for secondary stroke prevention in patients with AF, but with a much lower risk of intracerebral hemorrhage. Two recent large randomized trials failed to show superiority of direct oral anticoagulants over aspirin in ESUS patients. These findings prompt a reexamination of the ESUS concept, with the goal of improving specificity for detecting patients with a cardioembolic cause. Based on the negative trial results, there is renewed interest in the role of long-term cardiac monitoring for AF in patients who fit the current ESUS definition, as well as the clinical implication of detecting AF. Ongoing trials are exploring these questions. Current ESUS definitions do not accurately detect the patients who should be prescribed direct oral anticoagulants, potentially because occult AF is less common than expected in these patients and/or anticoagulants may be less beneficial in patients with ESUS but no AF than they are for patients with stroke with established AF. More specific criteria to identify patients who may be at higher risk for occult AF and reduce their risk of subsequent stroke have been developed and are being tested in ongoing clinical trials.

New Insights Regarding Prolonged Monitoring for Atrial Fibrillation

Various methods are available for detecting occult atrial fibrillation (AF), ranging from watches to implanted devices. For patients with a recent,

"Pill-in-Pocket" Anticoagulation for Atrial Fibrillation: Fiction, Fact, or Foolish?

"Pill-in-Pocket" Anticoagulation for Atrial Fibrillation: Fiction, Fact, or Foolish?

Analysis on severe fever with thrombocytopenia syndrome bunyavirus infection combined with atrial fibrillation under digital model detection

To heighten the diagnostic efficiency, in this study, the algebraic reconstruction technology (ART)-based echocardiography (ECG) was used to analyze severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) complicated by atrial fibrillation. From Jan. 2015 to Dec. 2019, 200 elderly patients with SFTSV infection and hypertrophic cardiomyopathy (HCM) admitted to our hospital were selected as the observation group, and 20 healthy volunteers were in the control group. Then 200 patients were randomly divided into two groups with 100 people in each group. One group received routine clinical observation after surgery, and the other group received artificial intelligence atrial fibrillation monitoring. ECG displayed the left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), left ventricular end diastolic volume index (EDVI), and end systolic volume index (ESVI) of patients. The accuracy and satisfaction of different methods in observation were recorded. The risk factors of postoperative atrial fibrillation in elderly patients with HCM were evaluated, and changes in their white blood cell levels were detected. The results showed that, there was a significant difference in ECG between normal people and patients after surgery. Also, differences were noted in accuracy and satisfaction of the two methods in observation group (P < 0.05). The atrial fibrillation group and the non-atrial fibrillation group showed notable differences in smoking history and age (P < 0.05); the white blood cell content of the atrial fibrillation group was 8.64 × 109, and that in non-atrial fibrillation group was 3.25 × 109. The content of ST-2 in postoperative atrial fibrillation group was 21.3 g/mL, and the content of Gal-3 was 9.57 g/mL, while the content of ST-2 in non-atrial fibrillation group was 17.24 g/mL, and the content of Gal-3 was 5.21 g/mL. There was no significant difference in LVEF, LVMI, EDVI, ESVI between postoperative atrial fibrillation and the non-atrial fibrillation group. In summary, ECG can effectively detect HCM, and the digital model demonstrated superb capabilities in monitoring atrial fibrillation after cardiac sympathetic block. The atrial fibrillation group showed a higher level of white blood cells after surgery and was more likely to develop SFTSV infection. Measures should be taken to prevent infection.

Head-to-head comparison of proprietary PPG and single-lead ECG algorithms for atrial fibrillation detection

Abstract Funding Acknowledgements Type of funding sources: None. Background Population based screening for atrial fibrillation (AF) has been suggested to reduce stroke. Photoplethysmography (PPG) deriving smartphone apps and single-lead electrocardiography (ECG) tools are attractive devices for screening due to their low cost, convenience, and accessibility. Automated algorithm analysis can serve as pre-screening or remote monitoring for AF, while confirmation on an ECG trace &amp;gt;30s is required to establish the diagnosis. This work directly compares the performance of proprietary algorithms on PPG vs single-lead ECG for the detection of AF. Purpose To evaluate and compare the diagnostic performance of a PPG-deriving smartphone app and a single-lead ECG-deriving handheld device for AF detection. Methods Patients were recruited from the cardiology ward. After obtaining written informed consent, demographic and medical information were collected. Patients were instructed to perform one measurement using a pulse-deriving smartphone app and one via a single-lead ECG handheld device. A 12-lead electrocardiogram (ECG) was collected and interpreted by a cardiologist as gold standard. Patients with atrial flutter were excluded, with additional exclusions for insufficient quality measurements and unsuccessful measurements resulting due to technical errors. Unclassified single-lead ECG measurements were handled as test-negative. Sensitivity, specificity and accuracy were calculated with respect to the reference diagnosis. McNemar’s analysis was performed to compare the sensitivity and specificity of the proprietary PPG and single-lead ECG AF detection algorithms. Results The median age in the study population (n = 300) was 70 years (interquartile range: 51-78), 56.3% were men, and the median CHA2DS2-VASc was 3 (interquartile range: 1-4) with an AF-prevalence of 32.3%. PPG signal and single‑lead ECG quality was sufficient in 272/300 (91.0%) and 278/298 (93.3%) participants, respectively. After excluding atrial flutter patients (n = 25) and insufficient quality measurements, the sensitivity and specificity were 97.6% (95% CI 93.8 to 99.3) and 94.1% (95% CI 86.8 to 98.1) for the PPG signal versus 95.7% (95% CI 91.4 to 98.3) and 91.1% (95% CI 83.2 to 96.1) for the single‑lead ECG signal, respectively. Results demonstrated a 96.4% (95% CI 93.2 to 98.3) accuracy for PPG and 94.1% (95% CI 90.4 to 96.6) for single-lead ECG. No significant differences in sensitivity (P = 0.453) or specificity (P = 0.219) between the proprietary PPG and single-lead ECG algorithms were found. Conclusion This study demonstrated equivalent diagnostic performance of PPG and single-lead ECG proprietary AF detection algorithms in smartphone apps.

Lower Extremity Arterial Disease as a Predictor of Incident Atrial Fibrillation and Cardiovascular Events

ObjectiveTo evaluate the relationship between peripheral arterial disease (PAD) and incident atrial fibrillation (AF) and its clinical and pathophysiologic implications on ischemic stroke and all-cause mortality. Patients and MethodsWe identified all adult patients in the Mayo Clinic Health System without a previous diagnosis of AF undergoing ankle-brachial index (ABI) testing for any indication from January 1, 1996, to June 30, 2018. Retrospective extraction of ABI data and baseline echocardiographic data was performed. The primary outcome of interest was incident AF. The secondary outcomes of interest were incident ischemic stroke and all-cause mortality. ResultsA total of 33,734 patients were included in the study. After adjusting for demographic and comorbidity variables, compared with patients who had normal ABI (1.0 to 1.39), there was an increased risk of incident AF in patients with low ABI (<1.0) (adjusted hazard ratio, 1.14; 95% CI, 1.06 to 1.22) and elevated ABI (≥1.4) (adjusted hazard ratio, 1.18; 95% CI, 1.06 to 1.31). The risk was greater in patients with increasing severity of PAD. Patients with abnormal ABIs had an increased risk of ischemic stroke and all-cause mortality. We found that patients with PAD and incident AF have certain baseline echocardiographic abnormalities. ConclusionIn this large cohort of ambulatory patients undergoing ABI measurement, patients with PAD were at increased risk for incident AF, ischemic stroke, and mortality. In these high-risk patients with abnormal ABI, particularly severe PAD and cardiac structural abnormalities, routine monitoring for AF and management of cardiovascular risk factors may be warranted.

A SCALABLE HYBRID MODEL FOR ATRIAL FIBRILLATION DETECTION

In this work, a scalable hybrid model is proposed for the purpose of screening and continuous monitoring of atrial fibrillation (AF) using electrocardiogram (ECG) signals collected from wearable ECG devices. The time series of RR intervals (with units in seconds) extracted from the ECG signal is fed into a recurrent neural network (RNN), and the bandpass filtered and scaled signal itself is fed into a convolutional neural network (CNN). At the post-processing stage, these two predictions are merged. An additional logistic regression model using statistical features of “pseudo” PR interval sequence is applied to aid making the final prediction. The proposed model is trained and validated on several datasets from PhysioNet and achieves a precision of 98.28% and a specificity of 99.82% on a dataset collected from several PhysioNet databases. This hybrid model has already been deployed through a WeChat applet, providing services those using wearable ECG devices, thus helping the screening and continuous out-of-hospital monitoring of the disease of AF.

Validation of an algorithm for continuous monitoring of atrial fibrillation using a consumer smartwatch.

Consumer devices with broad reach may be useful in screening for atrial fibrillation (AF) in appropriate populations. However, currently no consumer devices are capable of continuous monitoring for AF. The purpose of this study was to estimate the sensitivity and specificity of a smartwatch algorithm for continuous detection of AF from sinus rhythm in a free-living setting. We studied a commercially available smartwatch with photoplethysmography (W-PPG) and electrocardiogram (W-ECG) capabilities. We validated a novel W-PPG algorithm combined with a W-ECG algorithm in a free-living setting, and compared the results to those of a 28-day continuous ECG patch (P-ECG). A total of 204 participants completed the free-living study, recording 81,944 hours with both P-ECG and smartwatch measurements. We found sensitivity of 87.8% (95% confidence interval [CI] 83.6%-91.0%) and specificity of 97.4% (95% CI 97.1%-97.7%) for the W-PPG algorithm (every 5-minute classification); sensitivity of 98.9% (95% CI 98.1%-99.4%) and specificity of 99.3% (95% CI 99.1%-99.5%) for the W-ECG algorithm; and sensitivity of 96.9% (95% CI 93.7%-98.5%) and specificity of 99.3% (95% CI 98.4%-99.7%) for W-PPG triggered W-ECG with a single W-ECG required for confirmation of AF. We found a very strong correlation of W-PPG in quantifying AF burden compared to P-ECG (r = 0.98). Our findings demonstrate that a novel algorithm using a commercially available smartwatch can continuously detect AF with excellent performance and that confirmation with W-ECG further enhances specificity. In addition, our W-PPG algorithm can estimate AF burden. Further research is needed to determine whether this algorithm is useful in screening for AF in select at-risk patients.

Patient-reported outcomes in symptom-driven remote arrhythmia monitoring: evaluation of the Dutch HartWacht-telemonitoring programme.

There is limited quantitative evidence on the effect of symptom-driven telemonitoring for cardiac arrhythmias on patient-reported outcomes. We evaluated the effect of a symptom-driven remote arrhythmia monitoring programme on the patient-reported health-related quality of life (HRQoL), sense of safety, physical limitations, and self-management. This was an observational retrospective longitudinal study of the symptom-driven HartWacht-telemonitoring programme using a remote single-lead electrocardiogram monitoring system. Real-world patient data from participants who were enrolled in the telemonitoring programme for (suspected) symptomatic atrial fibrillation (AF) between July 2017 and September 2019 were evaluated. Primary outcomes were the patient-reported generic HRQoL, disease-specific HRQoL, sense of safety, physical limitations, and self-management at date of enrolment, 3 months and 6 months of follow-up. Outcomes were compared to a historical control group consisting of AF patients receiving standard care. A total of 109 participants in the HartWacht programme [59 men (54%); mean age 61 ± 11 years; 72% diagnosed AF] were included in complete case analysis. There was no significant change in HRQoL and sense of safety during follow-up. A significant improvement in the perceived physical limitations was observed. The level of self-management declined significantly during follow-up. Comparisons to the historic control group (n = 83) showed no difference between the patient-reported disease-specific HRQoL, sense of safety and physical limitations at 6 months of follow-up. Symptom-driven remote arrhythmia monitoring for AF does not seem to affect HRQoL and sense of safety, whereas the perceived physical limitations tend to improve. Patient-reported self-management declined during the first 6 months of participation.

Single-lead ECGs (AliveCor) are a feasible, cost-effective and safer alternative to 12-lead ECGs in community diagnosis and monitoring of atrial fibrillation

BackgroundCommunity management of atrial fibrillation (AF) often requires the use of electrocardiographic (ECG) investigation. Patients discharged following treatment of AF with fast ventricular response (fast AF) can require numerous ECGs...

The future of long-term monitoring following catheter and surgical intervention for atrial fibrillation.

Monitoring following catheter or surgical ablation for atrial fibrillation (AF) is an essential tool used to assess outcomes for research purposes and help guide clinical decision making. The most commonly used methods to monitor for postintervention AF include a variety of ambulatory external electrocardiogrammonitors, cardiac implantable electronic devices, and more recently, direct to consumer digital health technologies. The traditional metric of ablation success, recurrence > 30 s at 1 year, is below the detection capabilities of almost all monitoring techniques yet still undervalues the efficacy of AF interventions. Measures of AF burden reduction and duration give a more complete assessment of the impact of AF surgeries and ablation. As it is increasingly being recognized that AF burden and duration is related to stroke risk, long-term, inexpensive, noninvasive monitoring methods are needed. Smart phones and watches with AF-detecting capabilities, which are increasingly being used by the majority of U.S. adults, have emerged as viable options to achieve this goal, shifting the paradigm of AF monitoring to a more patient-centered approach.

Use of Oral Anticoagulation in a Real-World Population With Device Detected Atrial Fibrillation.

BackgroundGuideline recommendations for oral anticoagulation (OAC) in patients with atrial fibrillation (AF) are based on CHA2DS2‐VASc score alone. Patients with cardiac implantable electronic devices provide an opportunity to assess how the interaction between AF duration and CHA2DS2‐VASc score influences OAC prescription rates.Methods and ResultsData from the Optum de‐identified Electronic Health Record data set were linked to the Medtronic CareLink database of cardiac implantable electronic devices. An index date was assigned as the later of 6 months after device implant or 1 year after Electronic Health Record data availability. Maximum daily AF duration (no AF, 6 minutes–23.5 hours, and >23.5 hours) was assessed for 6 months before index date. OAC prescription rates were computed as a function of both AF duration and CHA2DS2‐VASc score. A total of 35 779 patients with CHA2DS2‐VASc scores ≥1 were identified, including 27 198 not prescribed OAC. Overall OAC prescription rate among the 12 938 patients with device‐detected AF >6 minutes was 36.7% and significantly higher in those with a maximum daily AF duration >23.5 hours (45.4%) compared with those with 6 minutes to 23.5 hours (28.7%). OAC prescription rates increased monotonically with both increasing AF duration and CHA2DS2‐VASc score, reaching a maximum of 67.2% for patients with AF >23.5 hours and a CHA2DS2‐VASc score ≥5.ConclusionsReal‐world prescription of OAC increased with both increasing duration of AF and CHA2DS2‐VASc score. This highlights the need for further research into the role of AF duration, stroke risk, and the need for anticoagulation in patients with devices capable of long‐term AF monitoring.

Economic evaluation of extended electrocardiogram monitoring for atrial fibrillation in patients with cryptogenic stroke.

Timely identification of occult atrial fibrillation following cryptogenic stroke facilitates consideration of oral anticoagulation therapy. Extended electrocardiography monitoring beyond 24 to 48 h Holter monitoring improves atrial fibrillation detection rates, yet uncertainty remains due to upfront costs and the projected long-term benefit. We sought to determine the cost-effectiveness of three electrocardiography monitoring strategies in detecting atrial fibrillation after cryptogenic stroke. A decision-analytic Markov model was used to project the costs and outcomes of three different electrocardiography monitoring strategies (i.e. 30-day electrocardiography monitoring, three-year implantable loop recorder monitoring, and conventional Holter monitoring) in acute stroke survivors without previously documented atrial fibrillation. The lifetime discounted costs and quality-adjusted life years were $206,385 and 7.77 quality-adjusted life years for conventional monitoring, $207,080 and 7.79 quality-adjusted life years for 30-day extended electrocardiography monitoring, and $210,728 and 7.88 quality-adjusted life years for the implantable loop recorder strategy. Additional quality-adjusted life years could be attained at a more favorable incremental cost per quality-adjusted life year with the implantable loop recorder strategy, compared with the 30-day electrocardiography monitoring strategy, thereby eliminating the 30-day strategy by extended dominance. The implantable loop recorder strategy was associated with an incremental cost per quality-adjusted life year gained of $40,796 compared with conventional monitoring. One-way sensitivity analyses indicated that the model was most sensitive to the rate of recurrent ischemic stroke. An implantable loop recorder strategy for detection of occult atrial fibrillation in patients with cryptogenic stroke is more economically attractive than 30-day electrocardiography monitoring compared to conventional monitoring and is associated with a cost per quality-adjusted life year gained in the range of other publicly funded therapies. The value proposition is improved when considering patients at the highest risk of recurrent ischemic stroke. However, the implantable loop recorder strategy is associated with increased health care costs, and the opportunity cost of wide scale implementation must be considered.

A robust ECG denoising technique using variable frequency complex demodulation

Background and objectiveElectrocardiogram (ECG) is widely used for the detection and diagnosis of cardiac arrhythmias such as atrial fibrillation. Most of the computer-based automatic cardiac abnormality detection algorithms require accurate identification of ECG components such as QRS complexes in order to provide a reliable result. However, ECGs are often contaminated by noise and artifacts, especially if they are obtained using wearable sensors, therefore, identification of accurate QRS complexes often becomes challenging. Most of the existing denoising methods were validated using simulated noise added to a clean ECG signal and they did not consider authentically noisy ECG signals. Moreover, many of them are model-dependent and sampling-frequency dependent and require a large amount of computational time. MethodsThis paper presents a novel ECG denoising technique using the variable frequency complex demodulation (VFCDM) algorithm, which considers noises from a variety of sources. We used the sub-band decomposition of the noise-contaminated ECG signals using VFCDM to remove the noise components so that better-quality ECGs could be reconstructed. An adaptive automated masking is proposed in order to preserve the QRS complexes while removing the unnecessary noise components. Finally, the ECG was reconstructed using a dynamic reconstruction rule based on automatic identification of the severity of the noise contamination. The ECG signal quality was further improved by removing baseline drift and smoothing via adaptive mean filtering. ResultsEvaluation results on the standard MIT-BIH Arrhythmia database suggest that the proposed denoising technique provides superior denoising performance compared to studies in the literature. Moreover, the proposed method was validated using real-life noise sources collected from the noise stress test database (NSTDB) and data from an armband ECG device which contains significant muscle artifacts. Results from both the wearable armband ECG data and NSTDB data suggest that the proposed denoising method provides significantly better performance in terms of accurate QRS complex detection and signal to noise ratio (SNR) improvement when compared to some of the recent existing denoising algorithms. ConclusionsThe detailed qualitative and quantitative analysis demonstrated that the proposed denoising method has been robust in filtering varieties of noises present in the ECG. The QRS detection performance of the denoised armband ECG signals indicates that the proposed denoising method has the potential to increase the amount of usable armband ECG data, thus, the armband device with the proposed denoising method could be used for long term monitoring of atrial fibrillation.