AF Screening Research Articles

Abstract 192: Comparative Clinical Effectiveness of Population-based Atrial Fibrillation Screening Using Wearable Devices: A Decision-Analytic Model

Introduction: Early diagnosis of AF via screening might prevent strokes. AF screening is endorsed in certain guidelines for individuals aged ≥65 years, yet many modalities and strategies exist. Determining the comparative effectiveness of contemporary screening strategies is critical to inform population-based screening interventions. Methods: We developed a decision-analytic model to evaluate 45 distinct AF screening strategies (defined using different modalities and screening intervals), and compared them to no screening within 50 million individuals matching the United States population aged ≥65 years. The primary outcome was quality-adjusted life-years (QALYs), with incident stroke, major bleeding, and AF true and false positive rates as secondary outcomes. Results: A total of 11 AF screening strategies were effective when compared to no screening (100-1200 QALYs gained per 100,000 individuals screened, Figure ). Of 11 effective strategies, 7 (63.6%) utilized wrist-worn wearables. Effective strategies reduced stroke incidence by 0.1-0.2/1,000 person-years [PY] (number needed to screen to prevent stroke 5,000-10,000), but increased major bleeding by 0.2-0.6/1,000 PY (number needed to screen to cause major bleed 1,667-5,000). Repeated screening with discrete modalities tended to reduce effectiveness by accruing false positives without substantial gain in true AF diagnoses, while increasing the monitoring duration using wrist-worn wearables increased effectiveness as long as a confirmatory test was utilized. Sensitivity analyses identified test specificity as a highly influential parameter on screening effectiveness. Conclusions: Population-based AF screening is likely effective when specific strategies are utilized. Wrist-worn wearables appear to be an important modality for effective clinician-guided AF screening. Future technological development should focus on maximizing specificity for AF detection.

Abstract 15336: Real-world Diagnostic Performance of Single-lead Handheld Electrocardiograms for Atrial Fibrillation Screening: The Vital-af Trial

Introduction: AF screening can detect undiagnosed AF, but concerns exist regarding false positives and downstream consequences. AF screening using single-lead handheld electrocardiograms (1L ECGs) is feasible, but diagnostic performance in a pragmatic screening setting is not well-understood. Methods: VITAL-AF is a cluster-randomized trial (NCT035115057) of population-based AF screening with 30-second 1L ECGs. Individuals aged ≥65 years receiving primary care in a study practice were eligible, with practices randomized to screening (n=8) or usual care (n=8). Screening was performed with the AliveCor Kardia 1L ECG (AliveCor US) administered by medical assistants. In addition to the AliveCor interpretation, all 1L ECGs were overread by cardiologists. We assessed the distribution of automated interpretations and predictive values using cardiologist 1L ECG overread as the gold standard. Results: Screening generated 38,190 tracings representing 16,496 individuals read by 13 cardiologists (median time to read: 10h, quartile 1: 5, quartile 3: 19). We removed 1,554 tracings overread as uninterpretable, resulting in 36,636 tracings in the analysis. A total of 27,251 (74.4%) tracings had an AliveCor interpretation of normal, 6,223 (17.0%) unclassified, 2,420 (6.6%) possible AF, and 742 (2.0%) no interpretation. The positive predictive value (PPV) of possible AF by AliveCor was 76.2% (95% CI 74.5-77.9, Figure ). The negative predictive values (NPVs) were 99.7% (95% CI 99.6-99.8) for normal, 92.3% (95% CI 91.6-92.9) for unclassified, and 87.1% (95% CI 84.4-89.4) for no interpretation. Of 2,502 tracings overread as AF, 482 (19.3%) were unclassified by AliveCor. Conclusions: In an elderly primary care population, the PPV of possible AF by AliveCor algorithm was modest, whereas the NPV of a normal interpretation was very high. Unclassified tracings were common and enriched for AF. Abnormal findings, including unclassified 1L ECG tracings, merit follow-up testing.

Artificial intelligence-enabled detection of paroxysmal atrial fibrillation from normal sinus ECGs in patients with coronary microvascular dysfunction

Abstract Background Artificial Intelligence (AI) algorithms enabled the detection of patients with paroxysmal atrial fibrillation (PAF) from a single normal sinus rhythm (NSR) ECG. Coronary microvascular dysfunction (CMD) is a precursor for coronary artery disease, which is a known risk factor for AF. Purpose The aim of this study is to examine the probability of PAF, according to AI-enabled algorithm estimation, in patients with CMD. Methods 1858 patients without persistent atrial fibrillation with signs and/or symptoms of ischemia and with non-obstructive CAD (<40% stenosis) who underwent invasive coronary microvascular functional assessment and the ECG closest to the functional assessment were included in this analysis. Patients with coronary flow velocity reserve (CFR) <2 in response to adenosine were labelled as endothelial-independent CMD; % increase in coronary blood flow (%ΔCBF) <50% in response to acetylcholine were labelled as endothelial-dependent CMD. Patients were categorized into 4 groups. G1: Normal (NL) CFR/NL %ΔCBF; G2: Abnormal (ABN) %ΔCBF only; G3: ABN CFR only; G4: ABL CFR & %ΔCBF. The probability of having PAF (%probAF) was calculated by a previously-trained and validated AI algorithm. AF Flag = %probAF >9%; which is a pre-set cut-off found to have the highest accuracy of identifying patients with PAF (Area Under the Curve = 0.87). Results Mean age for patients was 51.2±12.4 and 66.3% were females. 835 (45%) were in G1, 39 (2%) in G2, 911 (49%) in G3, and 73 (4%) in G4. Compared to G1 and G2, G3 and G4 were older, had more diabetes and higher smoking rates (p<0.05 for all). Furthermore, G4 had a significantly higher %probAF compared to other groups (Fig. 1). G4 were also more likely to be flagged by the algorithm as having PAF, even after adjusting for cardiovascular risk factors, with an odds ratio of 1.9 [CI 95% 1.1–3.3; p=0.03]) (Fig. 2). Conclusion Patients with combined CMD have a significantly higher probability of having PAF based on an AI-enabled algorithm. Further research is warranted to know if patients with CMD would benefit from formal AF screening at the time of diagnosis. Funding Acknowledgement Type of funding source: None

Mobile health technology-supported atrial fibrillation screening and integrated care: A report from the mAFA-II trial Long-term Extension Cohort

Background. In the mobile Atrial Fibrillation App (mAFA)-II trial, the use of mobile health (mHealth) technology, incorporating AF screening and integrated management strategy, was associated with improved short-term clinical outcomes. The aim of this study was to report adherence/persistence and long term (≥1 year) clinical outcomes of the mAFA-II trial, with mHealth-supported optimised stroke prevention, symptom control and comorbidity management.Methods. We studied an adult population screened for AF, where identified patients could enter a structured program of holistic and integrated care based on the ABC (Atrial fibrillation Better Care) pathway using mHealth with a mAFA intervention. In this cluster randomised trial, comparing mHeath intervention to usual care, the primary composite outcome was ‘stroke/thromboembolism, all-cause death and rehospitalization’.Results. The 1261 subjects (mean age 67.0 years, 38.0% female) who were followed up over one year (mean follow-up 687 (standard deviation, SD 191) days) in the intervention arm, had a lower risk of the composite outcome of ‘ischaemic stroke/systemic thromboembolism, death, and rehospitalization’ (hazard ratio, HR 0.18, 95% confidence interval, CI: 0.13–0.25, P < 0.001), compared to usual care (1212 subjects, mean age 70.1 years, 42.1% female). Of 842 patients using their smart devices for ‘Better symptom management’, 70.8% had good management adherence (monitoring time/follow-up since initial monitoring ≥ 70%), with the persistence of use of 91.7%.Conclusion. Amongst AF patients with long term use (≥1 year) of mHealth technology for optimising stroke prevention, symptom control and comorbidity management, adherence/persistence was good and associated with a reduction in adverse clinical outcomes.

Assessment of a standalone photoplethysmography (PPG) algorithm for detection of atrial fibrillation on wristband-derived data

IntroductionAtrial fibrillation (AF) is the most common cardiac arrhythmia in the developed world. Using photoplethysmography (PPG) and software algorithms, AF can be detected with high accuracy using smartphone camera-derived data. However, reports of diagnostic accuracy of standalone algorithms using wristband-derived PPG data are sparse, while this provides a means to perform long-term AF screening and monitoring. This study evaluated the diagnostic accuracy of a well-known standalone algorithm using wristband-derived PPG data. Materials and MethodsSubjects recruited from a community senior care organization were instructed to wear the Wavelet PPG wristband on one arm and the Alivecor KardiaBand one-lead-ECG wristband on the other. Three consecutive measurements (duration per measurement: 60 s for PPG and 30 s for one-lead ECG) were performed with both devices, simultaneously. The PPG data were analyzed by the Fibricheck standalone algorithm and the ECG data by the Kardia algorithm. The results were compared to a reference standard (interpretation of the one-lead ECG by two independent cardiologists). ResultsA total of 180 PPGs and one-lead ECGs were recorded in 60 subjects, with a mean age of 70±17. AF was identified in 6 (10%) of the users, two users (3%) were not classifiable by the PPG algorithm and 1 user (2%) was not classifiable by the one-lead ECG algorithm. The diagnostic performance (sensitivity/specificity/positive predictive value/negative predictive value/accuracy) on user level was 100/96/75/100/97% for the PPG wristband and 100/98/86/100/98% for the one-lead ECG wristband. ConclusionsIn a small real-world cohort of elderly people, the standalone Fibricheck AF algorithm can accurately detect AF using Wavelet wristband-derived PPG data. Results are comparable to the Alivecor Kardia one-lead ECG device, with an acceptable unclassifiable/bad quality rate. This opens the door for long-term AF screening and monitoring.

Pharmacists detecting atrial fibrillation in general practice: a qualitative focus group study.

BackgroundAtrial fibrillation (AF) affects up to 10% of people aged ≥65 years, yet a third of all cases remain undetected. Practice-based pharmacists are in an ideal position to facilitate opportunistic AF screening, while increasing general practice capacity at a time of workforce crisis.AimTo explore the perspectives of three stakeholder groups involved in the ‘Pharmacists Detecting Atrial Fibrillation’ (PDAF) study to elucidate the facilitators and barriers to pharmacist-led AF screening in general practice.Design & settingA qualitative study took place, comprising homogeneous focus groups with stakeholders in Kent, UK.MethodThe stakeholder groups — patients, general practice staff (GPS), and clinical pharmacists (CPs) — were recruited using convenience sampling. Audio-recordings were transcribed verbatim and analysed using a deductive Theoretical Domains Framework (TDF) approach.ResultsTwenty-five patients, four pharmacists, and nine practice staff participated in six focus groups. Three main themes were identified: knowledge and awareness; prioritisation of resources; and environmental considerations. The public’s lack of awareness of AF-related risks and pharmacist-led screening services was highlighted. Practice-based pharmacists were perceived as an underutilised educational resource which, together with novel electrocardiogram devices, enabled convenient access to screening while reducing GPs’ workload. Participants agreed that AF screening should be incorporated into personalised health checks and at-risk groups should be prioritised, such as care home residents. Patients favoured the general practice environment over the community pharmacy where concerns of privacy, staffing, and commercialisation were raised.ConclusionThe findings of this study support the introduction of pharmacist-led AF screening programmes in general practice surgeries. Commissioners should consider the added value of utilising CPs and focus on the delivery of AF screening within an integrated service.

Preventicus Heartbeats cost effective for AF screening

Preventicus Heartbeats cost effective for AF screening

Prediction models for atrial fibrillation applicable in the community: a systematic review and meta-analysis.

AimsAtrial fibrillation (AF) is a common arrhythmia associated with an increased stroke risk. The use of multivariable prediction models could result in more efficient primary AF screening by selecting at-risk individuals. We aimed to determine which model may be best suitable for increasing efficiency of future primary AF screening efforts.Methods and resultsWe performed a systematic review on multivariable models derived, validated, and/or augmented for AF prediction in community cohorts using Pubmed, Embase, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) through 1 August 2019. We performed meta-analysis of model discrimination with the summary C-statistic as the primary expression of associations using a random effects model. In case of high heterogeneity, we calculated a 95% prediction interval. We used the CHARMS (Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies) checklist for risk of bias assessment. We included 27 studies with a total of 2 978 659 unique participants among 20 cohorts with mean age ranging from 42 to 76 years. We identified 21 risk models used for incident AF risk in community cohorts. Three models showed significant summary discrimination despite high heterogeneity: CHARGE-AF (Cohorts for Heart and Aging Research in Genomic Epidemiology) [summary C-statistic 0.71; 95% confidence interval (95% CI) 0.66–0.76], FHS-AF (Framingham Heart Study risk score for AF) (summary C-statistic 0.70; 95% CI 0.64–0.76), and CHA2DS2-VASc (summary C-statistic 0.69; 95% CI 0.64–0.74). Of these, CHARGE-AF and FHS-AF had originally been derived for AF incidence prediction. Only CHARGE-AF, which comprises easily obtainable measurements and medical history elements, showed significant summary discrimination among cohorts that had applied a uniform (5-year) risk prediction window.ConclusionCHARGE-AF appeared most suitable for primary screening purposes in terms of performance and applicability in older community cohorts of predominantly European descent.

Abstract 134: Digital-AF II: Impact of Smartphone-Based Atrial Fibrillation Screening in the General Population for Primary Stroke Prevention

Background: Opportunistic AF screening for primary stroke prevention is recommended in patients aged above 65 based on stroke risk models. Logistics hamper uniform screening with 12-lead ECG. Novel technologies, e.g. photoplethysmography-based (PPG) apps, may overcome this, providing readily available screening at low cost. We assessed the feasibility of smartphone screening and the impact on subsequent clinical care. Methods: A media campaign educated on AF, recruited subjects, and gave access to a PPG-based app to assess the heart rhythm. Subjects were instructed to measure twice daily for 8 days. An algorithm classified the traces as regular, possible AF, non-AF irregularity, or insufficient quality. PPGs of possible irregularities or AF were reviewed by medical technicians and cardiologists. If AF was confirmed, a physician visit was recommended. Questionnaires collected data on clinical care. Results: In 2 weeks, 62,821 subjects onboarded, resulting in 588,336 60-second PPG traces. The screened population was 49±15 years, 58% was male. In 791 subjects (1.3%), AF was diagnosed by the algorithm and offline confirmed. This group was older (62±11 years, p&lt;0.001), more frequently male (76%, p&lt;0.001) and had a higher CHA2DS2-VASc score (1.00±1.00 vs 2.00±2.00, p&lt;0.001). The proportion with CHA2DS2-VASc ≥ 1 is 81.3% for the AF cohort vs 64.3% in non-AF cohort. The AF yield increased from 0.52% with 1 recording to 1.84% after 8 days. Of the AF patients, 335 (42%) were known, 373 (47%) newly identified, and 83 (11%) did not give this information. A physician was consulted by 138 (17%) newly identified patients, findings were confirmed in 71 (9%), 46 (6%) received antithrombotic therapy. Conclusion: This digital screening, targeting the general population and using only smartphones, demonstrates the feasibility to collect data in a scalable and low-cost way. Next to single timepoint ECG, twice-daily PPG may detect a significant number of asymptomatic AF patients.

Screening for Atrial Fibrillation Using a Mobile, Single-Lead Electrocardiogram in Canadian Primary Care Clinics

BackgroundAtrial fibrillation (AF), which affects 1% to 4% of the general population, is an important risk factor for stroke. New technologies for AF screening are now available, but their real-world application in clinical settings has not yet been thoroughly investigated. The aim of this project was to describe the introduction and feasibility of a mobile electrocardiogram (ECG) device for AF screening in a large-scale, undifferentiated population. MethodsA total of 184 Canadian primary care physicians were provided with a KardiaMobile ECG device (AliveCor) for 3 months. Physicians were asked to obtain a single 30-second ECG recording of all patients seen in their daily practice who were ≥65 years old and not previously diagnosed with AF. Evaluation of the Kardia device by physicians was measured using a Likert scale–based questionnaire. ResultsOne hundred thirty-three physicians (72%) reported their findings and completed the survey. A total of 7585 patients were screened (42% of eligible patients). AF was detected in 471 patients (6.2%). Anticoagulation therapy was initiated in 270 patients (57%). Physicians generally reported a high perceived clinical value (94%) and ease of integration (89%) of the device. ConclusionsPreviously undiagnosed AF is common in older individuals attending primary care clinics. The KardiaMobile ECG device appears to be an effective screening tool for AF with high physician acceptability. More research on the feasibility of such novel technologies is warranted for future consideration of integration in population-based screening programs.

Effectiveness of a Community-based AF Screening Program: A Pilot Study

Effectiveness of a Community-based AF Screening Program: A Pilot Study

Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: The Apple Heart Study

BackgroundSmartwatch and fitness band wearable consumer electronics can passively measure pulse rate from the wrist using photoplethysmography (PPG). Identification of pulse irregularity or variability from these data has the potential to identify atrial fibrillation or atrial flutter (AF, collectively). The rapidly expanding consumer base of these devices allows for detection of undiagnosed AF at scale.MethodsThe Apple Heart Study is a prospective, single arm pragmatic study that has enrolled 419,093 participants (NCT03335800). The primary objective is to measure the proportion of participants with an irregular pulse detected by the Apple Watch (Apple Inc, Cupertino, CA) with AF on subsequent ambulatory ECG patch monitoring. The secondary objectives are to: 1) characterize the concordance of pulse irregularity notification episodes from the Apple Watch with simultaneously recorded ambulatory ECGs; 2) estimate the rate of initial contact with a health care provider within 3 months after notification of pulse irregularity. The study is conducted virtually, with screening, consent and data collection performed electronically from within an accompanying smartphone app. Study visits are performed by telehealth study physicians via video chat through the app, and ambulatory ECG patches are mailed to the participants.ConclusionsThe results of this trial will provide initial evidence for the ability of a smartwatch algorithm to identify pulse irregularity and variability which may reflect previously unknown AF. The Apple Heart Study will help provide a foundation for how wearable technology can inform the clinical approach to AF identification and screening. (Am Heart J 2019;207:66–75.)

Feasibility and outcomes of atrial fibrillation screening using intermittent electrocardiography in a primary healthcare setting: A cross-sectional study.

BackgroundAtrial fibrillation (AF) is a major risk factor for ischemic stroke unless treated with an anticoagulant. Detecting AF can be difficult because AF is often paroxysmal and asymptomatic. The aims of this study were to develop a screening model to detect AF in a primary healthcare setting and to initiate oral anticoagulant therapy in high-risk patients to prevent stroke.MethodsThis was a cross-sectional study. All 70- to 74-year-old individuals registered at a single primary healthcare center in Stockholm were invited to participate in AF screening upon visiting the center during a ten-month period. Those who did not have contact with the center during this period were invited to participate by letter. Thirty-second intermittent ECG recordings were made twice a day using a handheld Zenicor device over a 2-week period in participants without AF. Oral anticoagulant therapy was offered to patients with newly detected AF.FindingsOf the 415 eligible individuals, a total of 324 (78.1%) patients participated in the study. The mean age of the participants was 72 years, 52.2% were female, and the median CHA2DS2-VASc score of the participants was 3. In the target population, 34 (8.2%) individuals had previously diagnosed AF. Among participants without previously known AF, 16 (5.5%) cases of AF were detected. The final AF prevalence in the target population was 12%. Oral anticoagulant therapy was successfully initiated in 88% of these patients with newly detected AF.ConclusionsThe AF screening project exhibited a high participation rate and resulted in a high rate of newly discovered AF; of these newly diagnosed patients, 88% could be treated with an oral anticoagulant.

Pharmacists detecting atrial fibrillation (PDAF) in primary care during the influenza vaccination season: a multisite, cross-sectional screening protocol

IntroductionAtrial fibrillation (AF) affects >6% of people aged 65 years or older. Left undetected and untreated, patients may develop significant cardiovascular complications and have a fivefold increased risk of suffering...

P867Yield of targeted AF screening in a high-risk cohort with chronic kidney disease, diabetes mellitus and cardiovascular disease

P867Yield of targeted AF screening in a high-risk cohort with chronic kidney disease, diabetes mellitus and cardiovascular disease

Study protocol for Smartphone Monitoring for Atrial fibrillation in Real-Time in India (SMART-India): a community-based screening and referral programme

IntroductionAtrial fibrillation (AF), the world’s most common arrhythmia, often goes undetected and untreated in low-resource communities, including India, where AF epidemiology is undefined. AF is an important risk factor for...

NHS Western Isles - Involving our Patients: Faster Access to Treatment for Hypertension in Primary Care

Introduction: Hypertension is the single most common risk factor for both cardiovascular and overall disease burden and mortality worldwide, medical treatment of hypertension mitigates this risk.1 Around 7 million people in the UK have undiagnosed hypertension and therefore do not know that they are at risk.2 Timely and accurate diagnosis of hypertension can improve clinical outcomes; patients waiting over a month and a half post high reading demonstrate progressively worse outcomes than those treated more promptly.3 NICE recommends ambulatory blood pressure monitoring (ABPM) to confirm or exclude a diagnosis of hypertension.4 However acknowledging that some patients find ABPM uncomfortable, home blood pressure monitoring is recommended as a suitable alternative4 which patients generally find a positive experience.5 Case for Change: Some NHS Western Isles patients are referred to secondary care for ABPM and in concordance nationally, delays were encountered and subsequently time to treatment initiation was prolonged with an increased number of patient contacts both clinically and administratively. The time between identifying a raised blood pressure and treatment leaves the patient unmanaged and vulnerable to exacerbation before treatment has commenced. Patients also had to make several journeys both to the practice and hospital with the communication process largely being paper led. In parallel, many (but not all) people wish to be more informed and involved with their own care, challenging the traditional divide between patients and professionals, and offering opportunities for better health through increased prevention and supported self-care.6 It is also recognised that by improving patients’ access to home monitoring, patients increase their interaction with, and understanding of their condition.7,8 This created an opportunity for NHS Western Isles to combine patient willingness to become more involved in their health with the benefits of supported home monitoring to provide their patients with the opportunity to play a key role in improving their own health outcomes. Based on previous evidence8 Florence9 was identified as the NHS owned clinically driven interactive self management tool that could enable a safe and effective transition to a 7 day home blood pressure monitoring pathway. Following clinical approval locally, home monitoring via Florence was offered to patients attending the pilot practice demonstrating a raised blood pressure. Impact: The redesigned pathway is now complete in 7 days from identification to treatment initiation and maximises opportunities for home monitoring to improve patient safety and engagement over the period; both patient and clinician experience has been positive. Thorough evaluation has taken place with the initial cohort of 13 patients (aged 26-73) years saving: 19 follow-up appointments (primary care) 71 patient contacts 44 patient journeys Identifying 4 cases of white coat hypertension Outcomes Demonstrated Patient: Faster diagnosis or exclusion of hypertension reduced patient uncertainty Confidence and ability to self-manage improved with convenient reminders to take readings and clinically approved advice once blood pressure readings submitted. Engagement in condition and/or symptoms improved Improved patient acceptance of new or increased medication A safe, supported alternative to ABPM providing patient choice in treatment planning Reduction in patient travel Clinician: Immediate initiation, faster access to diagnostic data to initiate treatment Real time access to accessible and exportable data to expedite and evidence treatment decisions. Improved patient safety during diagnostic process AF screening increased via monitors provided by the practice Supports development of a nurse-led service System: Reduced handoffs improved patient flow Reduction in patient contacts More cost effective pathway Reduction in administrative processes improves productivity Opportunity to support the delivery of person centred care when treatment planning Comments: The outcomes from the initial cohort confirmed that redesigned pathway provides sustainable and scalable learning for further adoption across primary care adding significant benefits to traditional ABPM or non-supported home monitoring practice. With a small proportion of the clinical time released reallocated to diagnostic result analysis, the application could also be extended to support diagnosis or monitoring of other conditions where patients can be supported to submit readings or symptoms from home. This was the first model within Scotland reviewing hypertension diagnosis pathways with Florence which formed the basis for a large scale implementation in NHS Lanarkshire. NHS Western Isles are collaborating with Scottish Centre for Telehealth and Telecare and NHS24 on a national pathway based on this methodology which has been adopted as part of a national evaluation model.

Screening of Atrial Fibrillation Using Wrist Photoplethysmography from a Fitbit Tracker

Background: Atrial Fibrillation is the most common clinically significant cardiac arrhythmia, estimated to affect between 2% ( 65 years of age) of the U.S. population. Screening and early detection of AF can help prevent associated stroke and cardiovascular disease. Commonly used monitoring devices are limited to short periods (< 4 weeks) and are usually employed in symptomatic subjects. Wrist-worn wearables equipped with photoplethysmography (PPG) could potentially aid in AF screening, as they can be easily worn by most people for extended periods of time. Objective: This study aimed to investigate the ability of wrist-based PPG to detect the presence of AF in subjects while at rest. Methods: This study was conducted with the approval of local institutional review boards, and all patients provided written, informed consent. The first dataset consisted of 9 patients with persistent AF and 13 subjects with normal sinus rhythm. For these 22 subjects, PPG and ECG data were collected while sitting stationary for 15 minutes (awake dataset). A second dataset consisted of 10 patients with persistent AF and 27 subjects with no known diagnosis of AF. These subjects were asked to wear a Fitbit wrist-band which recorded PPG and accelerometry data during sleep (sleep dataset, 73 total nights). There was no overlap between subjects in the awake and sleep datasets. Results: Data were analyzed in overlapping 1 or 5-minute windows. Pulse Rate Variability (PRV) features, PPG morphology features and accelerometer features were extracted for each window. An algorithm was trained on the awake dataset and was validated on the sleep dataset. The performance was 95.7% (98%) sensitivity (Se) and 0.8% (0.8%) False Positive Rate (FPR) for 1 min (5 min) windows. We also investigated the shortest duration of an AF episode that could be detected by using synthesized data. With 1 minute analysis windows, the algorithm was sensitive down to 40-second episodes. Using 5-minute intervals, episodes down to 3 minutes could be reliably detected. Conclusions: Wrist-bands equipped with PPG sensors can be used to detect atrial fibrillation during sleep or during awake, stationary periods. While reliable detection of short AF episodes can be challenging due to the noisy nature of PPG signals, we have demonstrated that select PPG features can enable accurate detection of AF down to 40 second periods. These findings suggest that wrist-worn devices equipped with a PPG sensor could be used to screen for AF in high-risk subjects or monitor patients post treatment, but are limited to cases where users are not moving or exercising. Additional, larger clinical studies are planned for the future to validate these promising early results and to validate the algorithm’s specificity against other forms of arrhythmia. [iproc 2017;3(1):e17]

44 Diagnostic yield of 7-day holter ecg monitoring for new af and association with comorbidities. outcomes in an all-comer cohort from a large teaching trust

Introduction Prolonged ECG monitoring is an increasingly advocated method to detect silent AF and other arrhythmias. Inevitably, the wider use of prolonged ECG monitoring will yield unexpected and serious findings requiring swift action. Here, we report the diagnostic yield of 7 day Holter ECG monitoring requested through primary and secondary care. We also highlight the clinical and Holter ECG parameters associated with new AF. Methods We analysed all 7 day Holter ECG tests in Sandwell and West Birmingham NHS Trust from 1st April 2014 to 30th April 2016, using Spacelabs Sentinel server running Pathfinder V 1.7.1. Tests were bookable by primary care and hospital physicians. Holter recordings from 364 patients, previously reported by cardiac physiologists were reviewed by physicians trained in Holter analysis. 46 patients had previously diagnosed AF and were excluded from the analysis. Here we present the results from a final cohort of 318 patients. Results Mean age of the patients was 59.2 years (median 56 years, IQR 43–72) and 55% were male. Average time of monitoring was 162.2 hours. Palpitations (56%), dizziness (16%), ischaemic stroke or TIA (15%), syncope (10%), and chest pain (3%) were reasons for referral. New AF was diagnosed in 25/318 patients. The pick-up rate of incidental AF was 7.86%. 9/48 (18.7%) of patients with CVA and 16/178 (8.9%) with palpitations had new AF. For 7 day Holters performed with intention to look for AF (stroke and palpitations) the combined diagnostic yield to pick up new AF was 11%. There was no AF detected for indications of dizziness, syncope or chest pain. Patients with newly diagnosed AF were older with mean age 71 years (CI 66–78, SD 17.3) vs. 57 years (CI 55–59, SD 17.6) for non-AF group (p=0.001), more often suffered from coronary artery disease (43% vs 18%, p=0.001), prior stroke or TIA (64% vs 23%, p=0.04), moderate to severe valvular heart disease (20% vs 6%, p=0.01), had higher occurrence of >250 supra ventricular ectopics/day (73% vs 60%, p=0.05) and atrial runs of more than 3 beats (55% vs 25%, 0=0.002 respectively). Heart rate parameters for patients with and without AF were not different in our cohort. Other medically relevant findings were 2nd degree AV block (9/318, 2.8%), 3rd degree AV block (2/318, 0.6%) and non-sustained VT (11/318, 3.4%). Conclusions Prolonged ECG monitoring in a real life cohort, especially in patients with high risk of AF, leads to higher diagnostic yield, with significant therapeutic consequences. It appears reasonable to provide open access to prolonged ECG monitoring to at-risk populations in primary and secondary care. Further analysis of risk factors for paroxysmal AF and systematic evaluations of treatment and outcomes after AF screening are warranted to define populations for screening for silent AF.

National AF screening likely to be cost effective in Ireland

National AF screening likely to be cost effective in Ireland