Symptoms and functional status of patients with atrial fibrillation: state of the art and future research opportunities

Photoplethysmography based atrial fibrillation detection: a continually growing field

Objective. Atrial fibrillation (AF) is a prevalent cardiac arrhythmia associated with significant health ramifications, including an elevated susceptibility to ischemic stroke, heart disease, and heightened mortality. Photoplethysmography (PPG) has emerged as a promising technology for continuous AF monitoring for its cost-effectiveness and widespread integration into wearable devices. Our team previously conducted an exhaustive review on PPG-based AF detection before June 2019. However, since then, more advanced technologies have emerged in this field.Approach. This paper offers a comprehensive review of the latest advancements in PPG-based AF detection, utilizing digital health and artificial intelligence (AI) solutions, within the timeframe spanning from July 2019 to December 2022. Through extensive exploration of scientific databases, we have identified 57 pertinent studies.Significance. Our comprehensive review encompasses an in-depth assessment of the statistical methodologies, traditional machine learning techniques, and deep learning approaches employed in these studies. In addition, we address the challenges encountered in the domain of PPG-based AF detection. Furthermore, we maintain a dedicated website to curate the latest research in this area, with regular updates on a regular basis.

Association Between Atrial Fibrillation Symptoms and Clinical Outcomes: A Prospective Multicenter Registry Study

The presence of symptoms plays an important role in determining whether to focus on rhythm control or rate control when treating atrial fibrillation (AF). Previous comparative studies on the clinical outcomes of symptomatic and asymptomatic AF have yielded inconsistent results, and a link between AF symptoms and left atrial (LA) remodeling is not established. Patients selected from the COmparison study of Drugs for symptom control and complication prEvention of AF (CODE-AF) registry, which is a prospective, multicenter study consisting of patients with non-valvular AF, were grouped into 2 groups: symptomatic and asymptomatic. The primary outcome was a composite of the following cardiovascular outcomes: all-cause death, ischemic stroke, transient ischemic attack, systemic embolism, myocardial infarction, and heart failure hospitalization. Of 10,210 patients with AF, 4,327 (42%) had symptomatic AF. The asymptomatic group had an older mean age, more men, and more patients with hypertension and diabetes mellitus than the symptomatic group. The asymptomatic group had a larger left atrium (LA) diameter (43.6 vs 42.2 mm, p <0.001) than the symptomatic group. During a median follow-up of 32.9 (29.5 to 36.4) months, the asymptomatic and symptomatic groups showed similar incidences of the primary outcome (1.44 vs 1.45 per 100 person-years; log-rank, p = 0.8). In conclusion, the absence of AF symptoms is associated with increased LA. However, symptomatic and asymptomatic patients with AF have a similar risk of cardiovascular outcomes. This suggests that beneficial treatment for AF may be considered regardless of whether patients have symptomatic or asymptomatic AF.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

Characterizing atrial fibrillation symptom improvement following de novo catheter ablation

AIMS

Atrial fibrillation (AF) symptom relief is a primary indication for catheter ablation, but AF symptom resolution is not well characterized. The study objective was to describe AF symptom documentation in electronic health records (EHRs) pre- and post-ablation and identify correlates of post-ablation symptoms.

METHODS AND RESULTS

We conducted a retrospective cohort study using EHRs of patients with AF (n = 1293), undergoing ablation in a large, urban health system from 2010 to 2020. We extracted symptom data from clinical notes using a natural language processing algorithm (F score: 0.81). We used Cochran's Q tests with post-hoc McNemar's tests to determine differences in symptom prevalence pre- and post-ablation. We used logistic regression models to estimate the adjusted odds of symptom resolution by personal or clinical characteristics at 6 and 12 months post-ablation. In fully adjusted models, at 12 months post-ablation patients, patients with heart failure had significantly lower odds of dyspnoea resolution [odds ratio (OR) 0.38, 95% confidence interval (CI) 0.25-0.57], oedema resolution (OR 0.37, 95% CI 0.25-0.56), and fatigue resolution (OR 0.54, 95% CI 0.34-0.85), but higher odds of palpitations resolution (OR 1.90, 95% CI 1.25-2.89) compared with those without heart failure. Age 65 and older, female sex, Black or African American race, smoking history, and antiarrhythmic use were also associated with lower odds of resolution of specific symptoms at 6 and 12 months.

CONCLUSION

The post-ablation symptom patterns are heterogeneous. Findings warrant confirmation with larger, more representative data sets, which may be informative for patients whose primary goal for undergoing an ablation is symptom relief.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Catheter ablation versus medical therapy in atrial fibrillation: an umbrella review of meta-analyses of randomized clinical trials

This umbrella review synthesizes data from 17 meta-analyses investigating the comparative outcomes of catheter ablation (CA) and medical treatment (MT) for atrial fibrillation (AF). Outcomes assessed were mortality, risk of hospitalization, AF recurrence, cardiovascular events, pulmonary vein stenosis, major bleeding, and changes in left ventricular ejection fraction (LVEF) and MLHFQ score. The findings indicate that CA significantly reduces overall mortality and cardiovascular hospitalization with high strength of evidence. The risk of AF recurrence was notably lower with CA, with moderate strength of evidence. Two associations reported an increased risk of pulmonary vein stenosis and major bleeding with CA, supported by high strength of evidence. Improved LVEF and a positive change in MLHFQ were also associated with CA. Among patients with AF and heart failure, CA appears superior to MT for reducing mortality, improving LVEF, and reducing cardiovascular rehospitalizations. In nonspecific populations, CA reduced mortality and improved LVEF but had higher complication rates. Our findings suggest that CA might offer significant benefits in managing AF, particularly in patients with heart failure. However, the risk of complications, including pulmonary vein stenosis and major bleeding, is notable. Further research in understudied populations may help refine these conclusions.

Combination of frequency- and time-domain characteristics of the fibrillatory waves for enhanced prediction of persistent atrial fibrillation recurrence after catheter ablation

Catheter ablation (CA) remains the cornerstone alternative to cardioversion for sinus rhythm (SR) restoration in patients with atrial fibrillation (AF). Unfortunately, despite the last methodological and technological advances, this procedure is not consistently effective in treating persistent AF. Beyond introducing new indices to characterize the fibrillatory waves (f-waves) recorded through the preoperative electrocardiogram (ECG), the aim of this study is to combine frequency- and time-domain features to improve CA outcome prediction and optimize patient selection for the procedure, given the absence of any study that jointly analyzes information from both domains. Precisely, the f-waves of 151 persistent AF patients undergoing their first CA procedure were extracted from standard V1 lead. Novel spectral and amplitude features were derived from these waves and combined through a machine learning algorithm to anticipate the intervention mid-term outcome. The power rate index (φ), which estimates the power of the harmonic content regarding the dominant frequency (DF), yielded the maximum individual discriminant ability of 64% to discern between individuals who experienced a recurrence of AF and those who sustained SR after a 9-month follow-up period. The predictive accuracy was improved up to 78.5% when this parameter φ was merged with the amplitude spectrum area in the DF bandwidth (A M S A L F ) and the normalized amplitude of the f-waves into a prediction model based on an ensemble classifier, built by random undersampling boosting of decision trees. This outcome suggests that the synthesis of both spectral and temporal features of the f-waves before CA might enrich the prognostic knowledge of this therapy for persistent AF patients.

Identification of Fatigue Subtypes and Their Correlates in Prevalent Heart Failure: A Secondary Analysis of the Atherosclerosis Risk in Communities Study

BACKGROUND

Among patients with heart failure (HF), fatigue is common and linked to quality of life and functional status. Fatigue is hypothesized to manifest as multiple types, with general and exertional components. Unique subtypes of fatigue in HF may require differential assessment and treatment to improve outcomes. We conducted this study to identify fatigue subtypes in persons with prevalent HF in the ARIC study (Atherosclerosis Risk in Communities) and describe the distribution of characteristics across subtypes.

METHODS

We performed a cross-sectional analysis of 1065 participants with prevalent HF at ARIC visit 5 (2011-2013). We measured exertional fatigue using the Modified Medical Research Council Breathlessness scale and general fatigue using the Patient Reported Outcomes Measurement Information System fatigue scale. We used latent class analysis to identify subtypes of fatigue. Number of classes was determined using model fit statistics, and classes were interpreted and assigned fatigue severity rating based on the conditional probability of endorsing survey items given class. We compared characteristics across classes using multinomial regression.

RESULTS

Overall, participants were 54% female and 38% Black with a mean age of 77. We identified 4 latent classes (fatigue subtypes): (1) high general/high exertional fatigue (18%), (2) high general/low exertional fatigue (27%), (3) moderate general/moderate exertional fatigue (20%), and (4) low/no general and exertional fatigue (35%). Female sex, Black race, lower education level, higher body mass index, increased depressive symptoms, and higher prevalence of diabetes were associated with higher levels of general and exertional fatigue.

CONCLUSIONS

We identified unique subtypes of fatigue in patients with HF who have not been previously described. Within subtype, general and exertional fatigue were mostly concordant in severity, and exertional fatigue only occurred in conjunction with general fatigue, not alone. Further understanding these fatigue types and their relationships to outcomes may enhance our understanding of the symptom experience and inform prognostication and secondary prevention efforts for persons with HF.

Continuous Atrial Fibrillation Monitoring From Photoplethysmography: Comparison Between Supervised Deep Learning and Heuristic Signal Processing

BACKGROUND

Continuous monitoring for atrial fibrillation (AF) using photoplethysmography (PPG) from smartwatches or other wearables is challenging due to periods of poor signal quality during motion or suboptimal wearing. As a result, many consumer wearables sample infrequently and only analyze when the user is at rest, which limits the ability to perform continuous monitoring or to quantify AF.

OBJECTIVES

This study aimed to compare 2 methods of continuous monitoring for AF in free-living patients: a well-validated signal processing (SP) heuristic and a convolutional deep neural network (DNN) trained on raw signal.

METHODS

We collected 4 weeks of continuous PPG and electrocardiography signals in 204 free-living patients. Both SP and DNN models were developed and validated both on holdout patients and an external validation set.

RESULTS

The results show that the SP model demonstrated receiver-operating characteristic area under the curve (AUC) of 0.972 (sensitivity 99.6%, specificity: 94.4%), which was similar to the DNN receiver-operating characteristic AUC of 0.973 (sensitivity 92.2, specificity: 95.5%); however, the DNN classified significantly more data (95% vs 62%), revealing its superior tolerance of tracings prone to motion artifact. Explainability analysis revealed that the DNN automatically suppresses motion artifacts, evaluates irregularity, and learns natural AF interbeat variability. The DNN performed better and analyzed more signal in the external validation cohort using a different population and PPG sensor (AUC, 0.994; 97% analyzed vs AUC, 0.989; 88% analyzed).

CONCLUSIONS

DNNs perform at least as well as SP models, classify more data, and thus may be better for continuous PPG monitoring.

Diagnostic Delay and Disease Burden in Primary Aldosteronism: An International Patient Survey

BACKGROUND

Primary aldosteronism (PA) is a common but underdiagnosed cause of hypertension. Many patients experience preventable end-organ injury due to delayed or missed diagnosis but data on the experience of patients are limited.

METHODS

We evaluated the lived experience of PA and determines factors associated with diagnostic delay through an international anonymous online cross-sectional survey, codesigned by researchers and PA consumers. We distributed the survey through academic medical centers, Amazon Mechanical Turk, Twitter, PA patient advocacy groups, and hypertension support groups on Facebook between March 21 and June 5, 2022.

RESULTS

Of 684 eligible respondents, 66.5% were women. Diagnostic delay (defined as ≥5 years between the diagnosis of hypertension and PA) was reported in 35.6%. Delay was more likely in women than in men (odds ratio, 1.55 [95% CI, 1.10-2.20]) and respondents with ≥3 comorbidities versus none (odds ratio, 1.77 [95% CI, 1.05-3.02]), ≥10 symptoms versus none (odds ratio, 2.73 [95% CI, 1.74-4.44]), and on ≥4 antihypertensive medications versus none (odds ratio, 18.23 [95% CI, 6.24-77.72]). Three-quarters of patients (74.4%) experienced reduced symptom burden following targeted PA treatment. Quality of life improved in 62.3% of patients, and greater improvement was associated with being a woman (odds ratio, 1.42, [95% CI, 1.02-1.97]), receiving adrenalectomy (odds ratio, 2.36 [95% CI, 1.67-3.35]), and taking fewer antihypertensive medications following diagnosis (odds ratio, 5.28 [95% CI, 3.55-7.90]).

CONCLUSIONS

One-third of patients with PA experienced prolonged diagnostic delays. Targeted treatment led to reduced symptom burden and improved quality of life. Gender differences in diagnostic delay and symptom burden are prominent. These findings suggest that routine screening for PA at the onset of hypertension may reduce diagnostic delay and facilitate timely diagnosis.

Optimizing the management of electrophysiology labs in Chinese hospitals using a discrete event simulation tool

BACKGROUND

The growing demand for electrophysiology (EP) treatment in China presents a challenge for current EP care delivery systems. This study constructed a discrete event simulation (DES) model of an inpatient EP care delivery process, simulating a generalized inpatient journey of EP patients from admission to discharge in the cardiology department of a tertiary hospital in China. The model shows how many more patients the system can serve under different resource constraints by optimizing various phases of the care delivery process.

METHODS

Model inputs were based on and validated using real-world data, simulating the scheduling of limited resources among competing demands from different patient types. The patient stay consists of three stages, namely: the pre-operative stay, the EP procedure, and the post-operative stay. The model outcome was the total number of discharges during the simulation period. The scenario analysis presented in this paper covers two capacity-limiting scenarios (CLS): (1) fully occupied ward beds and (2) fully occupied electrophysiology laboratories (EP labs). Within each CLS, we investigated potential throughput when the length of stay or operative time was reduced by 10%, 20%, and 30%. The reductions were applied to patients with atrial fibrillation, the most common indication accounting for almost 30% of patients.

RESULTS

Model validation showed simulation results approximated actual data (137.2 discharges calculated vs. 137 observed). With fully occupied wards, reducing pre- and/or post-operative stay time resulted in a 1-7% increased throughput. With fully occupied EP labs, reduced operative time increased throughput by 3-12%.

CONCLUSIONS

Model validation and scenario analyses demonstrated that the DES model reliably reflects the EP care delivery process. Simulations identified which phases of the process should be optimized under different resource constraints, and the expected increases in patients served.

Cardioversion strategy impacts rate control during recurrences in patients with paroxysmal atrial fibrillation: A subanalysis of the RACE 7 ACWAS trial

BACKGROUND

In the Rate Control versus Electrical Cardioversion Trial 7-Acute Cardioversion versus Wait and See, patients with recent-onset atrial fibrillation (AF) were randomized to either early or delayed cardioversion.

AIM

This prespecified sub-analysis aimed to evaluate heart rate during AF recurrences after an emergency department (ED) visit identified by an electrocardiogram (ECG)-based handheld device.

METHODS

After the ED visit, included patients (n = 437) were asked to use an ECG-based handheld device to monitor for recurrences during the 4-week follow-up period. 335 patients used the handheld device and were included in this analysis. Recordings from the device were collected and assessed for heart rhythm and rate. Optimal rate control was defined as a target resting heart rate of <110 beats per minute (bpm).

RESULTS

In 99 patients (29.6%, mean age 67 ± 10 years, 39.4% female, median 6 [3-12] AF recordings) a total of 314 AF recurrences (median 2 [1-3] per patient) were identified during follow-up. The average median resting heart rate at recurrence was 100 ± 21 bpm in the delayed vs 112 ± 25 bpm in the early cardioversion group (p = .011). Optimal rate control was seen in 68.4% [21.3%-100%] and 33.3% [0%-77.5%] of recordings (p = .01), respectively. Randomization group [coefficient -12.09 (-20.55 to -3.63, p = .006) for delayed vs. early cardioversion] and heart rate on index ECG [coefficient 0.46 (0.29-0.63, p < .001) per bpm increase] were identified on multivariable analysis as factors associated with lower median heart rate during AF recurrences.

CONCLUSION

A delayed cardioversion strategy translated into a favorable heart rate profile during AF recurrences.

The validity and reliability of Indonesian version of atrial fibrillation effect on quality of life (AFEQT) questionnaire for atrial fibrillation patients

BACKGROUND

More than 60% of patients with atrial fibrillation (AF) have a significant health-related quality of life (HRQoL) impairment. HRQoL, a patient-reported outcome (PRO), has become an important endpoint to assess treatment success in AF patients. The Atrial Fibrillation Effect on Quality of Life (AFEQT) questionnaire is an AF-specific HRQoL tool shown to be feasible, reliable, and valid, with translations in various languages. Since this questionnaire has never been translated or validated in Indonesian, we aimed to determine the validity and reliability of the Indonesian version of the AFEQT questionnaire for AF patients.

RESULTS

This cross-sectional, observational study was conducted in the Integrated Cardiovascular Service Polyclinic, Cipto Mangunkusumo Hospital, Indonesia, from December 2021 to March 2022. A total of 30 participants were recruited for cross-cultural adaptation process, which consisted of translation and adaptation process, and a total of 102 participants were consecutively recruited to participate in the validation process, which consisted of validity test (construct validity) and reliability tests (internal consistency and test-retest). The retest was conducted within a 1-2-week interval after the baseline assessment, by analyzing the intraclass correlation coefficient (ICC). The construct validity was determined by multitrait scaling analysis, and the convergent and divergent validity was compared to SF-36 domains. Multitrait scaling analysis revealed that all items in the Indonesian version of the AFEQT questionnaire had a strong negative correlation towards their respective domains (r -0.639--0.960). For convergent and divergent validity, AFEQT domains had weak to strong positive correlations to all SF-36 domains (r 0.338-0.693). This questionnaire also had acceptable internal consistency (Cronbach's α for overall score: 0.947; Domains: Symptoms: 0.818, Daily Activities: 0.943, Treatment Concern: 0.894, and Treatment Satisfaction: 0.865), as well as moderate-to-good test-retest reliability (0.521-0.828).

CONCLUSIONS

The Indonesian version of the AFEQT questionnaire has good validity and reliability for assessing quality of life of atrial fibrillation patients in Indonesia.

Changes in cardiac output, rhythm regularity, and symptom severity after electrical cardioversion of atrial fibrillation

OBJECTIVES

Symptoms in atrial fibrillation (AF) range from none to disabling. The physiological correlates of AF symptoms are not well characterized. This study investigated the association between physiological parameters and symptom severity before and after electrical cardioversion (EC) of AF.

DESIGN

We studied 44 patients with persistent AF (age 66.2 ± 7.9 years, 16% females) 4 ± 2 days before and 5 ± 2 days after EC. Physiological parameters included cardiac output (CO; non-invasive inert gas rebreathing), heart rate (HR), RR variability and resting and ambulatory blood pressure (BP). Symptoms and quality of life (QoL) were assessed by the modified European Heart Rhythm Association score (mEHRA), the Atrial Fibrillation Effect on Quality of Life (AFEQT) and the Symptom Checklist for frequency and severity of symptoms (SCL).

RESULTS

28 of 44 patients were still in sinus rhythm (SR) at post EC evaluation. Those in SR had a decreased HR (-15.4 ± 13.1 bpm, p < 0.001), and an increased CO (+0.8 ± 0.7 L/min, p < 0.001) as compared to those with recurrent AF. Changes in CO after EC correlated with symptom improvement as scored by AFEQT (r = 0.36; p < 0.05), AFEQT symptoms subscore (r = 0.46; p < 0.01), SCL for frequency (r = 0.62; p < 0.01) and severity (r = 0.33; p < 0.05) of symptoms, and the mEHRA score (r = 0.50; p < 0.01). A decrease in RR variability showed similar correlations with these measures of symptom improvement.

CONCLUSIONS

Improvements in symptoms and quality of life experienced by patients after electrical conversion of atrial fibrillation are correlated with an increase in CO and a decreased RR variability.

Quality of life among patients with atrial fibrillation: A theoretically-guided cross-sectional study

BACKGROUND

Patients with atrial fibrillation (AF) have significantly lower health-related quality of life (HRQoL) compared to the general population and patients with other heart diseases. The research emphasis on the influence of AF symptoms on HRQoL overshadows the role of individual characteristics. To address this gap, this study's purpose was to test an incremental predictive model for AF-related HRQoL following an adapted HRQoL conceptual model that incorporates both symptoms and individual characteristics.

METHODS

Patients attending an AF specialty clinic were invited to complete an online survey. Hierarchical regression analyses were conducted to examine whether individual characteristics (overall mental health, perceived stress, sex, age, AF knowledge, household and recreational physical activity) incremented prediction of HRQoL and AF treatment satisfaction beyond AF symptom recency and overall health.

RESULTS

Of 196 participants (mean age 65.3 years), 63% were male and 90% were Caucasian. Most reported 'excellent' or 'good' overall and mental health, had high overall AF knowledge scores, had low perceived stress scores, and had high household and recreation physical activity. The mean overall AF Effect On Quality-Of-Life Questionnaire (AFEQT) and AF treatment satisfaction scores were 70.62 and 73.84, respectively. Recency of AF symptoms and overall health accounted for 29.6% of the variance in overall HRQoL and 20.2% of the variance in AF treatment satisfaction. Individual characteristics explained an additional 13.6% of the variance in overall HRQoL and 7.6% of the variance in AF treatment satisfaction. Perceived stress and household physical activity were the largest contributors to overall HRQoL, whereas age and AF knowledge made significant contributions to AF treatment satisfaction.

CONCLUSIONS

Along with AF symptoms and overall health, individual characteristics are important predictors of HRQoL and AF treatment satisfaction in AF patients. In particular, perceived stress and household physical activity could further be targeted as potential areas to improve HRQoL.

Association between the atrial tachyarrhythmia recurrence period and long-term major adverse clinical events following catheter ablation for atrial fibrillation

Background

We previously demonstrated the clinical events in patients who underwent catheter ablation (CA) for atrial fibrillation (AF). Data on the association between the period of atrial tachyarrhythmia (ATA) recurrence after CA and long-term major adverse clinical events (MACE) remain unclear. In this study, we evaluated this issue in patients with systolic impairment (left ventricular ejection fraction < 50%) and heart failure with preserved ejection fraction (HFpEF).

Methods

We retrospectively collected data from 81 patients with systolic impairment and 83 patients with HFpEF who underwent CA for AF at our institution (median follow-up: 4.9 [3.6, 6.6] years). In each group, we compared the cumulative incidence of long-term MACE (since 1 year after CA) between patients with and without ATA recurrence at three follow-up periods (3, 6 months, and 1 year after index CA). We evaluated the period of recurrence, which was the most beneficial predictor of MACE among the periods.

Results

In the systolic impairment group, the cumulative long-term MACE incidence was significantly higher in patients with ATA recurrence than in those without it within 6 months and 1 year (P = 0.04 and P = 0.01, respectively). Recurrence within 1 year showed the highest feasibility for predicting long-term MACE (area under the curve with 95% confidence interval [CI]:0.73 [0.61-0.84]). However, there was no difference in the incidence of MACE between patients with and without recurrence in a group with HFpEF in each period.

Conclusion

ATA recurrence within 1 year could predict long-term MACE in patients with systolic impairment, but not in patients with HFpEF.

Clinical and economic outcomes associated with use of anti-arrhythmic drugs versus ablation in atrial fibrillation

Aim: To evaluate the clinical and economic impact of antiarrhythmic drugs (AADs) compared with ablation both as individual treatments and as combination therapy without/with considering the order of treatment among patients with atrial fibrillation (AFib). Materials & methods: A budget impact model over a one-year time horizon was developed to assess the economic impact of AADs (amiodarone, dofetilide, dronedarone, flecainide, propafenone, sotalol, and as a group) versus ablation across three scenarios: direct comparisons of individual treatments, non-temporal combinations, and temporal combinations. The economic analysis was conducted in accordance with CHEERS guidance as per current model objectives. Results are reported as costs per patient per year (PPPY). The impact of individual parameters was evaluated using one-way sensitivity analysis (OWSA). Results: In direct comparisons, ablation had the highest annual medication/procedure cost ($29,432), followed by dofetilide ($7661), dronedarone ($6451), sotalol ($4552), propafenone ($3044), flecainide ($2563), and amiodarone ($2538). Flecainide had the highest costs for long-term clinical outcomes ($22,964), followed by dofetilide ($17,462), sotalol ($15,030), amiodarone ($12,450), dronedarone ($10,424), propafenone ($7678) and ablation ($9948). In the non-temporal scenario, total costs incurred for AADs (group) + ablation ($17,278) were lower compared with ablation alone ($39,380). In the temporal scenario, AADs (group) before ablation resulted in PPPY cost savings of ($22,858) compared with AADs (group) after ablation ($19,958). Key factors in OWSA were ablation costs, the proportion of patients having reablation, and withdrawal due to adverse events. Conclusion: Utilization of AADs as individual treatment or in combination with ablation demonstrated comparable clinical benefits along with costs savings in patients with AFib.

Characterising symptom clusters in patients with atrial fibrillation undergoing catheter ablation

OBJECTIVE

This study aims to leverage natural language processing (NLP) and machine learning clustering analyses to (1) identify co-occurring symptoms of patients undergoing catheter ablation for atrial fibrillation (AF) and (2) describe clinical and sociodemographic correlates of symptom clusters.

METHODS

We conducted a cross-sectional retrospective analysis using electronic health records data. Adults who underwent AF ablation between 2010 and 2020 were included. Demographic, comorbidity and medication information was extracted using structured queries. Ten AF symptoms were extracted from unstructured clinical notes (n=13 416) using a validated NLP pipeline (F-score=0.81). We used the unsupervised machine learning approach known as Ward's hierarchical agglomerative clustering to characterise and identify subgroups of patients representing different clusters. Fisher's exact tests were used to investigate subgroup differences based on age, gender, race and heart failure (HF) status.

RESULTS

A total of 1293 patients were included in our analysis (mean age 65.5 years, 35.2% female, 58% white). The most frequently documented symptoms were dyspnoea (64%), oedema (62%) and palpitations (57%). We identified six symptom clusters: generally symptomatic, dyspnoea and oedema, chest pain, anxiety, fatigue and palpitations, and asymptomatic (reference). The asymptomatic cluster had a significantly higher prevalence of male, white and comorbid HF patients.

CONCLUSIONS

We applied NLP and machine learning to a large dataset to identify symptom clusters, which may signify latent biological underpinnings of symptom experiences and generate implications for clinical care. AF patients' symptom experiences vary widely. Given prior work showing that AF symptoms predict adverse outcomes, future work should investigate associations between symptom clusters and postablation outcomes.

Cardiac rehabilitation for heart failure and atrial fibrillation: a propensity- matched study

BACKGROUND

Atrial fibrillation (AF) is common in individuals with heart failure (HF). Individuals with HF and AF may have a reduced functional capacity and quality of life (QoL) which leads to hospital admission and burden on clinical services. Evidence supported the effect of exercise training in individuals with HF. However, there is no existing data on the effectiveness of comprehensive cardiac rehabilitation (CR) in individuals with coexisting HF and AF.

AIM

To explore the effect of CR in individuals with HF and AF compared with those with HF and no-coexisting AF.

METHODS

Using CR database, individuals with HF and AF were identified and propensity matched to those with no coexisting AF. The change in incremental shuttle walking test, Heart Disease Quality of Life questionnaire, Hospital Anxiety and Depression Scores were compared between groups pre-CR and post-CR.

RESULTS

149 individuals were propensity matched from each group. The mean±SD age of the matched sample was 73.4±8 years, body mass index 29±5.5 kg/m2, left ventricular ejection fraction 35.2±9.8% and 56% were male.A statistically significant improvements in exercise capacity, heart disease QoL, anxiety and depression scores were observed within each group. There were no significant differences between groups for any of these outcome measures.

CONCLUSIONS

Individuals with HF and AF gain a similar improvement in exercise capacity and health related QoL outcomes as individuals with no coexisting AF following CR. The presence of AF did not compromise the effectiveness of CR.

Validity of MENARI plus (self-pulse assessment and clinical scoring) mobile apps for detecting atrial fibrillation in high-risk population

BACKGROUND

Even before it is clinically diagnosed, atrial fibrillation (AF) can cause a stroke. This study validates self-pulse assessment and clinical scoring (MENARI Plus) based on android apps.

OBJECTIVE

The aim of this study was to examine the validity of AF screening using MENARI Plus compared with an ECG recording.

METHODS

We collected a total of 1385 subjects from high-risk population according to CHA2DS2-VASc score ≥2, attending 8 primary care centers (PCCs) in Malang between July 2021 and December 2021. Every participant underwent self-pulse assessment, and then was evaluated for MENARI Plus Score on android Apps. These cases had been classified as low or high probability for AF (cut-off score 7). After that, electrocardiography examinations were performed and classified with AF and Sinus Rhythm group.

RESULTS

In this study, the mean age of these patients was 61.5 ± 6.9 years old. We found that 156/1385 (11%) patients had AF. There were 68/156 (43.5%) new cases of AF. The sensitivity for self-pulse palpation was 73.1% (95% CI: 68%-76%) and specificity was 68.3% (95% CI: 65%-72%). MENARI Plus had an area under the receiver operating curve (AUC) of 0.86 (95% CI: 0.82-0.89) with sensitivity per measurement occasion was (84%, 95% CI: 82%-88%) and specificity was (87.9%, 95% CI: 82%-90%).

CONCLUSION

In this study, we found that MENARI Plus has high sensitivity and specificity for AF. It is therefore useful for ruling out AF. It may also be a useful screen that can be applied opportunistically for previously undetected AFs.

Predicting ischemic stroke risk from atrial fibrillation based on multi-spectral fundus images using deep learning

Background

Ischemic stroke (IS) is one of the most common serious secondary diseases of atrial fibrillation (AF) within 1 year after its occurrence, both of which have manifestations of ischemia and hypoxia of the small vessels in the early phase of the condition. The fundus is a collection of capillaries, while the retina responds differently to light of different wavelengths. Predicting the risk of IS occurring secondary to AF, based on subtle differences in fundus images of different wavelengths, is yet to be explored. This study was conducted to predict the risk of IS occurring secondary to AF based on multi-spectrum fundus images using deep learning.

Methods

A total of 150 AF participants without suffering from IS within 1 year after discharge and 100 IS participants with persistent arrhythmia symptoms or a history of AF diagnosis in the last year (defined as patients who would develop IS within 1 year after AF, based on fundus pathological manifestations generally prior to symptoms of the brain) were recruited. Fundus images at 548, 605, and 810 nm wavelengths were collected. Three classical deep neural network (DNN) models (Inception V3, ResNet50, SE50) were trained. Sociodemographic and selected routine clinical data were obtained.

Results

The accuracy of all DNNs with the single-spectral or multi-spectral combination images at the three wavelengths as input reached above 78%. The IS detection performance of DNNs with 605 nm spectral images as input was relatively more stable than with the other wavelengths. The multi-spectral combination models acquired a higher area under the curve (AUC) scores than the single-spectral models.

Conclusions

The probability of IS secondary to AF could be predicted based on multi-spectrum fundus images using deep learning, and combinations of multi-spectrum images improved the performance of DNNs. Acquiring different spectral fundus images is advantageous for the early prevention of cardiovascular and cerebrovascular diseases. The method in this study is a beneficial preliminary and initiative exploration for diseases that are difficult to predict the onset time such as IS.

Cognitive Behavioral Therapy Improves Quality of Life in Patients With Symptomatic Paroxysmal Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is often associated with troubling symptoms leading to impaired quality of life (QoL) and high health care use. Symptom preoccupation, that is, fear of cardiac-related symptoms and avoidance behavior, potentially contributes to disability in AF but is not targeted by current interventions.

OBJECTIVES

We sought to evaluate the effect of online cognitive behavior therapy (AF-CBT) on QoL in patients with symptomatic paroxysmal AF.

METHODS

Patients with symptomatic paroxysmal AF (n = 127) were randomly assigned to receive AF-CBT (n = 65) or standardized AF education (n = 62). Online AF-CBT lasted 10 weeks and was therapist guided. The main components were exposure to cardiac-related symptoms and reduction of AF-related avoidance behavior. Patients were evaluated at baseline, posttreatment, and at the 3-month follow-up. Primary outcome was AF-specific QoL as assessed by the Atrial Fibrillation Effect on Quality of Life summary score (range: 0-100) at the 3-month follow-up. Secondary outcomes included AF-specific health care consumption and AF burden assessed by 5-day continuous electrocardiogram recording. The AF-CBT group was followed for 12 months.

RESULTS

AF-CBT led to large improvements in AF-specific QoL (Atrial Fibrillation Effect on Quality of Life summary score) by 15.0 points (95% CI: 10.1-19.8; P < 0.001). Furthermore, AF-CBT reduced health care consumption by 56% (95% CI: 22-90; P = 0.025). The AF burden remained unchanged. Results on self-assessed outcomes were sustained 12 months after treatment.

CONCLUSIONS

In patients with symptomatic paroxysmal AF, online CBT led to large improvements in AF-specific QoL and reduced health care use. If these results are replicated, online CBT may constitute an important addition to AF management. (Internet-Delivered Cognitive Behavior Therapy for Atrial Fibrillation; NCT03378349).

MANAGEMENT OF ATRIAL FIBRILLATION, VENTRICULAR ARRHYTHMIA, LEFT VENTRICULAR DYSFUNCTION, AND SUBSEQUENT CARDIOPATHOLOGIC EVALUATION IN AN ORANGUTAN (PONGO PYGMAEUS × ABELII)

A 37-yr-old male vasectomized hybrid orangutan (Pongo pygmaeus × abelii) was diagnosed with left ventricular dysfunction during a preventative health care examination. Treatment was initiated with carvedilol. The following year, this orangutan was evaluated for intermittent lethargy. Following observation of an irregular cardiac rhythm during an echocardiogram, a lead II electrocardiogram revealed atrial fibrillation and ventricular arrhythmia. Additional treatment included amiodarone, furosemide, spironolactone, clopidogrel, and aspirin. An improved activity level was noted, and follow-up testing showed restoration of a sinus rhythm, reduced frequency of ventricular arrhythmia, and improved left ventricular function. The orangutan died 27 mon after initial diagnosis of heart disease, and a complete necropsy was performed. This article describes successful diagnosis and management of structural and arrhythmic heart disease in an orangutan, emphasizing the role of cardiac disease screening and behavioral training in apes, as well as the value of matching thorough antemortem and postmortem cardiac evaluation.

[Tactics of anticoagulant therapy in patients with cardiac implantable electronic devices and subclinical atrial fibrillation: A review]

Screening for atrial fibrillation (AF) has attracted considerable attention recently. Of special interest are patients with cardiac implantable electronic devices (CIEDs) that allow for recording episodes of atrial arrhythmias of various durations, including asymptomatic ones, in which case they are referred to as subclinical atrial fibrillation (SCAF). The available data suggest that the risk of thromboembolic events varies between patients with SCAF and clinically overt AF. As of today, the question regarding anticoagulant therapy in patients with SCAF remains unresolved. The article presents an overview of previous and ongoing studies on this issue, as well as current guidelines on anticoagulant use in patients with SCAF and CIEDs.

Insertable cardiac monitoring devices versus external cardiac monitoring for detecting atrial fibrillation and preventing the recurrence of stroke: A systematic review and meta-analysis

BACKGROUND

Atrial Fibrillation (AF) is a major risk factor for stroke, which is the second leading cause of death worldwide. It remains uncertain whether insertable cardiac monitors (ICMs) enhance the ability to recognize AF over external cardiac monitoring in patients who have experienced a stroke.

AIM

We conducted a systematic review and meta-analysis to determine whether ICM devices are more effective than external cardiac monitoring for the detection of AF in stroke patients.

METHODS

We included studies that reported an AF detection rate in stroke patients with a follow-up of at least 12 months. We analyzed the data of 1233 patients from 3 randomized control trials (RCTs).

RESULTS

When compared to external cardiac monitoring, ICM devices (Medtronic Reveal LINQ and Reveal XT) showed a significantly higher detection rate of AF (RR = 5.04, 95% CI = 2.93-8.68; p < 0.05; ARR = 10.47%, NNT = 10). The ICM arm had significantly higher usage of oral anticoagulants (OAC) as compared to the control arm. (RR = 2.76, 95% CI = 1.89-4.02, p < 0.05). Additionally, ICM usage was associated with a higher incidence of mild to moderate adverse events (RR = 10.52, 95% CI =1.35-82.14; p = 0.02) and a higher number of severe adverse events as compared to the control arm (RR = 7.61, 95% CI = 1.36-42.51; p = 0.02).

CONCLUSION

ICM devices are associated with better detection rates of AF and higher usage of OAC as compared to external cardiac monitoring in post-stroke patients. However, ICM insertion is associated with a higher incidence of mild/moderate and severe adverse effects.

The Efficacy of Telemedicine Rehabilitation Programs In Regard Of Risk Factors Control In Patients With Paroxysmal Atrial Fibrillation Aftercatheter Ablation

Aim      To evaluate changes in traditional risk factors (RF) during cardiac rehabilitation (CR) programs with remote support in patients with paroxysmal atrial fibrillation (AF) after catheter ablation (CA).Material and methods  The lack of control of cardiovascular RFs is a predictor for AF recurrence after CA, development of complications, and decreased life expectancy. Telemedical CR programs may improve the control of RF and enhance the CR efficacy. This randomized controlled clinical study in three parallel groups included 135 patients aged 35 to 79 years. In groups 1 and 2, CR programs with remote support were performed, which included a single personal consulting for the disease, achieving control of all patient's RFs, and remote support during 3 months (group 1, by phone and group 2, by e-mail). Participants of group 3 received standard recommendations. Body weight, blood pressure (BP), blood lipids, smoking status, and physical activity (PA) were determined at baseline and at 12 months after CA with the IPAQ questionnaire.Results In both intervention groups at 12 months, there were positive changes in RF: body weight index decreased by 3.6 % in group 1 (р=0.01) and by 2.3 % in group 2 (р=0.002) vs. 0 in the control group; systolic BP decreased by 7.1 % (p&lt;0.001) and 1.5 % (p=0.003) in groups 1 and 2 (vs. increases by 3.3 % in group 2); total cholesterol decreased by 9.4 % (p&lt;0.001) and by 6.3 % (p=0.003), respectively, (vs. 0 in group 3); values of metabolic equivalents (METs) used for walking increased by 55.0 % (р=0.014), 75.0 % (р=0.001), and 1.4 % in groups 1, 2 and 3, respectively. No significant intergroup differences in the frequency of AF recurrence, repeated CA, and hospitalizations were found.Conclusion      CR programs with remote support provide improved control of BP, body weight, blood cholesterol, and AF in patients with AF after CA, according to the results of the one-year follow-up.

Multidisciplinary Integrated Care in Atrial Fibrillation (MICAF): A Systematic Review and Meta-Analysis

Objective: To assess the effectiveness of multidisciplinary integrated care in the clinical outcomes of atrial fibrillation patients.Methods: Medline, EMBASE, and the CENTRAL trials registry of the Cochrane Collaboration were searched for articles on multidisciplinary integrated care in atrial fibrillation patients. The systematic review and meta-analysis included six and five articles, respectively, that compared the outcomes between the integrated care group and control group.Results: Multidisciplinary integrated care was concomitant with a decrease in all-cause mortality (OR 0.52, 95%CI 0.36-0.74, P=0.0003) and cardiovascular hospitalization (OR 0.66, 95%CI 0.49-0.89, P=0.007). Multidisciplinary integrated care had no significant impact on major adverse cardiovascular event (MACE) (OR 0.76, 95%CI 0.37-1.53, P=0.44), cardiovascular deaths (OR 0.49, 95% CI 0.21-1.17, P=0.11), atrial fibrillation (AF)-related hospitalization (OR 0.76, 95%CI 0.53-1.09, P=0.14), major bleeding (OR 1.02, 95%CI 0.59-1.75, P=0.94), minor bleeding (OR 1.12, 95%CI 0.55-2.26, P=0.76), and cerebrovascular events (OR 0.72, 95%CI 0.45-1.18, P=0.19).Conclusion: In comparison to usual care, a multidisciplinary integrated care approach (i.e., nurse-led care along with usual specialist care) in AF patients is associated with reduced all-cause mortality and cardiovascular hospitalization.

The Virtual Inclusive Digital Health Intervention Design to Promote Health Equity (iDesign) Framework for Atrial Fibrillation: Co-design and Development Study

Background

Smartphone ownership and mobile app use are steadily increasing in individuals of diverse racial and ethnic backgrounds living in the United States. Growing adoption of technology creates a perfect opportunity for digital health interventions to increase access to health care. To successfully implement digital health interventions and engage users, intervention development should be guided by user input, which is best achieved by the process of co-design. Digital health interventions co-designed with the active engagement of users have the potential to increase the uptake of guideline recommendations, which can reduce morbidity and mortality and advance health equity.

Objective

We aimed to co-design a digital health intervention for patients with atrial fibrillation, the most common cardiac arrhythmia, with patient, caregiver, and clinician feedback and to describe our approach to human-centered design for building digital health interventions.

Methods

We conducted virtual meetings with patients with atrial fibrillation (n=8), their caregivers, and clinicians (n=8). We used the following 7 steps in our co-design process: step 1, a virtual meeting focused on defining challenges and empathizing with problems that are faced in daily life by individuals with atrial fibrillation and clinicians; step 2, a virtual meeting focused on ideation and brainstorming the top challenges identified during the first meeting; step 3, individualized onboarding of patients with an existing minimally viable version of the atrial fibrillation app; step 4, virtual prototyping of the top 3 ideas generated during ideation; step 5, further ranking by the study investigators and engineers of the ideas that were generated during ideation but were not chosen as top-3 solutions to be prototyped in step 4; step 6, ongoing engineering work to incorporate top-priority features in the app; and step 7, obtaining further feedback from patients and testing the atrial fibrillation digital health intervention in a pilot clinical study.

Results

The top challenges identified by patients and caregivers included addressing risk factor modification, medication adherence, and guidance during atrial fibrillation episodes. Challenges identified by clinicians were complementary and included patient education, addressing modifiable atrial fibrillation risk factors, and remote atrial fibrillation episode management. Patients brainstormed more than 30 ideas to address the top challenges, and the clinicians generated more than 20 ideas. Ranking of the ideas informed several novel or modified features aligned with the Theory of Health Behavior Change, features that were geared toward risk factor modification; patient education; rhythm, symptom, and trigger correlation for remote atrial fibrillation management; and social support.

Conclusions

We co-designed an atrial fibrillation digital health intervention in partnership with patients, caregivers, and clinicians by virtually engaging in collaborative creation through the design process. We summarize our experience and describe a flexible approach to human-centered design for digital health intervention development that can guide innovative clinical investigators.

Preoperative Prediction of Catheter Ablation Outcome in Persistent Atrial Fibrillation Patients through Spectral Organization Analysis of the Surface Fibrillatory Waves

Catheter ablation (CA) is a commonly used treatment for persistent atrial fibrillation (AF). Since its medium/long-term success rate remains limited, preoperative prediction of its outcome is gaining clinical interest to optimally select candidates for the procedure. Among predictors based on the surface electrocardiogram, the dominant frequency (DF) and harmonic exponential decay (γ) of the fibrillatory waves (f-waves) have reported promising but clinically insufficient results. Hence, the main goal of this work was to conduct a broader analysis of the f-wave harmonic spectral structure to improve CA outcome prediction through several entropy-based measures computed on different frequency bands. On a database of 151 persistent AF patients under radio-frequency CA and a follow-up of 9 months, the newly introduced parameters discriminated between patients who relapsed to AF and those who maintained SR at about 70%, which was statistically superior to the DF and approximately similar to γ. They also provided complementary information to γ through different combinations in multivariate models based on lineal discriminant analysis and report classification performance improvement of about 5%. These results suggest that the presence of larger harmonics and a proportionally smaller DF peak is associated with a decreased probability of AF recurrence after CA.

Perception of atrial fibrillation symptoms: Impact on quality of life and treatment in older adults

BACKGROUND

In managing older adults with atrial fibrillation (AF), their symptomatology impacts their well-being and may inform treatment decision-making. We examined AF symptom perception, its impact on quality of life (QoL), and its relation to treatment strategies in older adults with AF.

METHODS

Data were obtained from older adults with AF enrolled in a multicenter study conducted at clinic sites in Massachusetts and Georgia between 2016 and 2018. Participants were stratified into three age groups: 65-74 (youngest-old), 75-84 (middle-old), and ≥85 (oldest). Perception of AF symptoms was assessed by participant self-report during their clinic visit and at study enrollment by the Atrial Fibrillation Effect on Quality-of-Life Questionnaire which assessed cardiac-specific and non-specific, non-cardiac AF symptoms and their impact on QoL. Treatment strategies (rate or rhythm control) utilized were ascertained from electronic medical records.

RESULTS

Among the 1184 participants (mean age 75 years, 48% women, 86% Non-Hispanic White), 51% were aged 65-74 years, 36% were 75-84 years, and 13% were ≥ 85 years. The most commonly reported AF symptoms were non-specific, non-cardiac symptoms (fatigue, dyspnea, lightheadedness) with similar prevalence and impact on QoL in all age groups. Cardiac-specific AF symptoms (palpitations, irregular heartbeat, pause in heart activity) were less prevalent, but most commonly reported by the youngest participants (65-74 years), who endorsed considerable impact of these symptoms on their QoL. Overall, those who reported experiencing any AF symptoms during their clinic visit were more likely to have received rhythm compared with rate control (OR: 1.56; 95% CI: 1.18-2.04) with similar findings for all age groups except those aged ≥85 years.

CONCLUSIONS

Our findings suggest a high prevalence of non-specific, non-cardiac symptoms among older adults with AF and that cardiac-specific AF symptoms may exert considerable impact on their QoL. The presence of any AF symptoms may drive more rhythm control in a majority of older adults.

Mobile app-based symptom-rhythm correlation assessment in patients with persistent atrial fibrillation

BACKGROUND

The assessment of symptom-rhythm correlation (SRC) in patients with persistent atrial fibrillation (AF) is challenging. Therefore, we performed a novel mobile app-based approach to assess SRC in persistent AF.

METHODS

Consecutive persistent AF patients planned for electrical cardioversion (ECV) used a mobile app to record a 60-s photoplethysmogram (PPG) and report symptoms once daily and in case of symptoms for four weeks prior and three weeks after ECV. Within each patient, SRC was quantified by the SRC-index defined as the sum of symptomatic AF recordings and asymptomatic non-AF recordings divided by the sum of all recordings.

RESULTS

Of 88 patients (33% women, age 68 ± 9 years) included, 78% reported any symptoms during recordings. The overall SRC-index was 0.61 (0.44-0.79). The study population was divided into SRC-index tertiles: low (<0.47), medium (0.47-0.73) and high (≥0.73). Patients within the low (vs high) SRC-index tertile had more often heart failure and diabetes mellitus (both 24.1% vs 6.9%). Extrasystoles occurred in 19% of all symptomatic non-AF PPG recordings. Within each patient, PPG recordings with the highest (vs lowest) tertile of pulse rates conferred an increased risk for symptomatic AF recordings (odds ratio [OR] 1.26, 95% coincidence interval [CI] 1.04-1.52) and symptomatic non-AF recordings (OR 2.93, 95% CI 2.16-3.97). Pulse variability was not associated with reported symptoms.

CONCLUSIONS

In patients with persistent AF, SRC is relatively low. Pulse rate is the main determinant of reported symptoms. Further studies are required to verify whether integrating mobile app-based SRC assessment in current workflows can improve AF management.

A case series of acute responses to high-intensity interval training in four males with permanent atrial fibrillation

Background

Atrial fibrillation (AF) is a serious medical condition and a burgeoning patient population. Chronic exercise training, including high-intensity interval training (HIIT), has been shown to improve symptoms and quality of life in patients with AF. Yet, the acute responses to HIIT in this population remain understudied, leaving clinicians and patients hesitant about prescribing and engaging in high-intensity exercise, respectively.

Case summary

This case series describes acute exercise responses [i.e. power output, heart rate (HR), blood pressure (BP), ratings of perceived exertion (RPE), symptoms] to 10 weeks (3 days/week) of HIIT. Participants were four white males (58–80 years old) with permanent AF, co-morbidities (diabetes, coronary artery disease, Parkinson’s disease), and physical limitations. The increases in HR and BP during HIIT were modest across all participants, regardless of age and medication use. Differences in RPE were observed; the oldest participant perceived the sessions as more challenging despite a lower HR response. All patients complied with the HIIT prescription of 80–100% of peak power output by week 4. No adverse events were reported.

Discussion

Patients’ concerns regarding high-intensity exercise may discourage them from participating in HIIT, our results demonstrated no abnormal HR or BP (e.g. hypotension) responses during HIIT or cool-down. These findings align with the typical exercise responses noted in other cardiovascular populations. Notwithstanding the high metabolic demands of HIIT, male patients with permanent AF tolerated HIIT without problem. Further investigation of HIIT as an approach to enable those with AF to recover physical capacity and minimize symptomatology is warranted.

Atrial Fibrillation With Myocardial Infarction Presenting as a Progressive Worsening Fatigue in a Young Male

Atrial fibrillation (AF) is one of the most common arrhythmia exhibiting a dramatic rise in prevalence with associated increased risk of stroke, heart failure, and death. No standard symptoms have been categorized yet to set a gold standard in diagnosing this clinical attribute. A highly variable symptoms array has increased the challenges of management in terms of AF. An obvious relationship has not been established between symptoms and the onset or recurrence of arrhythmia. We present a case of a 43-year-old male patient who complained of chronic fatigue as a primary symptom and was diagnosed with AF with myocardial infarction.

Impact of COVID-19 on patients awaiting ablation for atrial fibrillation

Objective

Atrial fibrillation (AF) ablation services were significantly affected by the COVID-19 pandemic. We aimed to evaluate a symptom-based clinician prioritisation scheme for waiting list management compared with patient-completed quality of life (QoL) scores. We also sought to understand factors influencing QoL, particularly the impact of COVID-19, on patients awaiting AF ablation, via a bespoke questionnaire.

Methods

Patients awaiting AF ablation were sent two QoL questionnaires (Atrial Fibrillation Effect on QualiTy of Life (AFEQT) and EuroQol 5D (EQ5D-5L)) and the bespoke questionnaire. At a separate time point, patients were categorised as C1—urgent, C2—priority or C3—routine by their cardiologist based on review of clinic letters.

Results

There were 118 patients included with priority categorisation available for 86 patients. Median AFEQT scores were lower in C2 (30.4; 17.2–51.9) vs C3 patients (56.5; 32.1–74.1; p<0.01). Unplanned admission occurred in 3 patients in C3 with AFEQT scores of <40. Although 65 patients had AF symptoms during the pandemic, 43.1% did not seek help where they ordinarily would have. An exercise frequency of ≥3–4 times a week was associated with higher AFEQT (56.5; 41.2–74.1; p<0.001) and EQ5D (0.84; 0.74–0.88; p<0.0001) scores.

Conclusion

The QoL of patients awaiting AF ablation is impaired and AFEQT helps to identify patients at risk of admission, over and above physician assessment. COVID-19 influenced patients seeking medical attention with symptomatic AF when they normally would. Regular exercise is associated with better QoL in patients awaiting AF ablation.

Anemia and iron deficiency in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac tachyarrhythmia and has a rising global prevalence. Given the increasing burden of AF-related symptoms and complications, new approaches to management are required. Anemia and iron deficiency are common conditions in patients with AF. Furthermore, emerging evidence suggests that the presence of anemia may be associated with worse outcome in these patients. The role of anemia and iron deficiency has been extensively explored in other cardiovascular states, such as heart failure and ischemic heart disease. In particular, the role of iron repletion amongst patients with heart failure is now an established treatment modality. However, despite the strong bidirectional inter-relationship between AF and heart failure, the implications of anemia and iron-deficiency in AF have been scarcely studied. This area is of mechanistic and clinical relevance given the potential that treatment of these conditions may improve symptoms and prognosis in the increasing number of individuals with AF. In this review, we summarise the current published literature on anemia and iron deficiency in patients with AF. We discuss AF complications such as stroke, bleeding, and heart failure, in addition to AF-related symptoms such as exercise intolerance, and the potential impact of anemia and iron deficiency on these. Finally, we summarize current research gaps on anemia, iron deficiency, and AF, and underscore potential research directions.

Atrial Fibrillation's Influence on Short Sleep Duration Increases the Risk of Fatness in Management Executives

This study explored whether atrial fibrillation (AF)’s influence on short sleep duration (SD) increases the subsequent risk of fatness in management executives. This study included 25,953 healthy individuals working as management executives with ages ranging from 35 to 65 years (19,100 men and 6853 women) who participated in a qualifying physical filter program from 2006 to 2017 in Taiwan. Men and women who slept < 4 h had a 4.35-fold and 5.26-fold higher risk of developing AF than those who slept 7−8 h normally. Men and women who slept < 4 h had a 6.44-fold and 9.62-fold higher risk of fatness than those who slept 7−8 h. Men and women with AF had a 4.52-fold and 6.25-fold higher risk of fatness than those without AF. It showed that AF induced by short SD increases the risk of fatness. A short SD can predict an increased risk of fatness among management executives in Taiwan.

Compressed Deep Learning to Classify Arrhythmia in an Embedded Wearable Device

The importance of an embedded wearable device with automatic detection and alarming cannot be overstated, given that 15-30% of patients with atrial fibrillation are reported to be asymptomatic. These asymptomatic patients do not seek medical care, hence traditional diagnostic tools including Holter are not effective for the further prevention of associated stroke or heart failure. This is likely to be more so in the era of COVID-19, in which patients become more reluctant on hospitalization and checkups. However, little literature is available on this important topic. For this reason, this study developed efficient deep learning with model compression, which is designed to use ECG data and classify arrhythmia in an embedded wearable device. ECG-signal data came from Korea University Anam Hospital in Seoul, Korea, with 28,308 unique patients (15,412 normal and 12,896 arrhythmia). Resnets and Mobilenets with model compression (TensorFlow Lite) were applied and compared for the diagnosis of arrhythmia in an embedded wearable device. The weight size of the compressed model registered a remarkable decrease from 743 MB to 76 KB (1/10000), whereas its performance was almost the same as its original counterpart. Resnet and Mobilenet were similar in terms of accuracy, i.e., Resnet-50 Hz (97.3) vs. Mo-bilenet-50 Hz (97.2), Resnet-100 Hz (98.2) vs. Mobilenet-100 Hz (97.9). Here, 50 Hz/100 Hz denotes the down-sampling rate. However, Resnets took more flash memory and longer inference time than did Mobilenets. In conclusion, Mobilenet would be a more efficient model than Resnet to classify arrhythmia in an embedded wearable device.

The Asymptomatic Patient with Atrial Fibrillation, previously reported in some but now found in many

Investigators in Japan evaluated echocardiographic and hemodynamic findings in patients with paroxysmal atrial fibrillation, comparing the findings of asymptomatic patients with patients who had symptomatic atrial fibrillation. Transseptal measurements of left atrial pressure were obtained. The multivariate analysis showed that patients with asymptomatic atrial fibrillation had significantly lower E/e on echo and lower rates of change of peak LA pressure in sinus rhythm or with high right atrial pacing. Patients with asymptomatic atrial fibrillation have preserved diastolic function and significantly less increase in LA pressure during atrial fibrillation. Although asymptomatic atrial fibrillation has generally been shown to be present in approximately 25% of patients with atrial fibrillation, new technologies of digital monitoring have revealed documentation of an increased number of patients with asymptomatic atrial fibrillation. This article is protected by copyright. All rights reserved.

Cut-off values of 6-min walk test and sit-to-stand test for determining symptom burden in atrial fibrillation

Background

Since symptomatology is a major predictor of quality of life and an endpoint for the management of atrial fibrillation (AF), practical approaches for objectively interpreting symptom burden and functional impairment are needed.

Aims

We aimed to provide cut-off values for two frequently used field tests to be able to objectively interpret symptom burden in atrial fibrillation.

Methods

One hundred twenty-five patients with AF were evaluated with European Heart Rhythm Association (EHRA) score, 6-min walk test (6MWT), 30 s sit-to-stand test (30 s-STST), Short-Form 36 (SF-36), International Physical Activity Questionnaire-Short Form (IPAQ-SF), and spirometry. Patients with EHRA 1 were classified as “asymptomatic”, and those with EHRA 2–4 as “symptomatic”. Cut-off values of 6MWT and 30 s-STST for discriminating between these patients were calculated.

Results

The optimal cut-off value was “450 m” for 6MWT (sensitivity: 0.71; specificity of 0.79) and “11 repetitions” for 30 s-STST (sensitivity 0.77; specificity of 0.70). Area under ROC curve was 0.75 for both tests (p < 0.001). Discriminative properties of the two tests were similar, and they were significantly correlated (r = 0.58; p < 0.001). Subgroup analysis revealed patients below cut-off values also had worse outcomes in SF-36, IPAQ-SF, and spirometry.

Conclusions

In patients with AF, walking < 450 m in 6MWT or performing < 11 repetitions in 30 s-STST indicates increased symptom burden, as well as impaired exercise capacity, quality of life, physical activity participation, and pulmonary function. These cut-off values may help identifying patients who may require adjustments in their routine treatment or who may benefit from additional rehabilitative approaches.

Symptoms and health-related quality of life 5 years after catheter ablation of atrial fibrillation

Objectives

To investigate the effect of catheter ablation (CA) on symptoms and health‐related quality of life (HRQoL) after 5 years, and analyze predictors of recurrence of symptoms.

Background

The primary indication for CA of atrial fibrillation (AF) is to reduce symptoms and improve HRQoL where long‐term follow‐up are sparse.

Methods

In this observational, long‐term, single‐center study, patients were recruited from Linköping University Hospital, Sweden. They were aged ≥18 years and had been referred for CA from November 2011 until June 2019. Arrhythmia‐specific symptoms and HRQoL were assessed by patient‐reported outcome measures (PROMs) with the Arrhythmia‐Specific questionnaire in Tachycardia and Arrhythmia (ASTA).

Results

In the study were 1521 patients, 69% men, mean age 62 years. At baseline, 87% of the patients and at the 5‐year follow‐up 80% of those eligible filled out the ASTA questionnaire. At follow‐up, 50% reported freedom from symptoms, 18% had >50% symptom reduction, 14% had a minor reduction, while 18% reported no effect or a worsening of symptoms. Factors predicting symptoms were female gender (hazard ratio [HR]: 1.8; 1.2–2.8), body mass index ≥ 35 (HR: 3.9; 1.6–9.8), and ischemic heart disease (IHD) (HR: 2.6; 1.2–5.9). After 5 years, breathlessness during activity, weakness/fatigue, and tiredness were still the most common symptoms; regarding HRQoL they were impaired physical ability and deteriorated life situation.

Conclusions and Clinical Implications

This clinical cohort of patients with AF evaluated through PROMs showed that CA had long‐lasting effects on symptoms and HRQoL and that the use of PROMs in clinical routines was feasible. Factors predicting symptoms after CA were female gender, IHD, and obesity, an important reminder to encourage lifestyle management.

Analyzing artificial intelligence systems for the prediction of atrial fibrillation from sinus-rhythm ECGs including demographics and feature visualization

Atrial fibrillation (AF) is an abnormal heart rhythm, asymptomatic in many cases, that causes several health problems and mortality in population. This retrospective study evaluates the ability of different AI-based models to predict future episodes of AF from electrocardiograms (ECGs) recorded during normal sinus rhythm. Patients are divided into two classes according to AF occurrence or sinus rhythm permanence along their several ECGs registry. In the constrained scenario of balancing the age distributions between classes, our best AI model predicts future episodes of AF with area under the curve (AUC) 0.79 (0.72–0.86). Multiple scenarios and age-sex-specific groups of patients are considered, achieving best performance of prediction for males older than 70 years. These results point out the importance of considering different demographic groups in the analysis of AF prediction, showing considerable performance gaps among them. In addition to the demographic analysis, we apply feature visualization techniques to identify the most important portions of the ECG signals in the task of AF prediction, improving this way the interpretability and understanding of the AI models. These results and the simplicity of recording ECGs during check-ups add feasibility to clinical applications of AI-based models.

Serum Beta-2 Microglobulin: A Possible Biomarker for Atrial Fibrillation

BACKGROUND Atrial fibrillation (AF) is the most common persistent arrhythmia that can cause complications (including stroke). Therefore, its diagnosis and treatment require increased attention. Although beta-2 microglobulin (b2-MG) is a novel marker of cardiovascular disease, its role in AF has not been evaluated. MATERIAL AND METHODS We conducted a case-control study with 61 patients who had normal heart rhythm (control group) and 60 patients with AF (research group). We analyzed the serum b2-MG levels in both groups and performed multivariate analysis to assess the correlation between b2-MG and left atrial remodeling. In addition, b2-MG levels were compared between the left atrial blood and peripheral venous blood of another set of 57 patients with AF, who underwent cryoballoon ablation. RESULTS There were no statistically significant differences in the baseline characteristics (age, sex, history of hypertension, diabetes mellitus, previous stroke, coronary heart disease, and estimated glomerular filtration rate) of the control and research groups. The left atrial anteroposterior diameters (LAD) and left ventricular end-systolic diameters in the AF group were significantly larger compared to the control group (P<0.01). Serum ß2-MG levels in patients with AF were significantly higher (P<0.01) and positively correlated with the LAD (B-coefficient 25.482, 95% CI 14.410~36.554, P<0.01), serum ß2-MG levels in the left atrial blood were significantly higher than those in peripheral venous blood (P<0.01), and serum ß2-MG levels were an independent predictor of AF. CONCLUSIONS With the development of atrial fibrillation, the serum ß2-MG levels increase and are closely related to the left atrial remodeling due to AF. Therefore, ß2-MG can be an effective biomarker for predicting AF.

A Higher Polygenic Risk Score Is Associated with a Higher Recurrence Rate of Atrial Fibrillation in Direct Current Cardioversion-Treated Patients

Background and Objectives: Recurrence of atrial fibrillation (AF) within six months after sinus rhythm restoration with direct current cardioversion (DCC) is a significant treatment challenge. Currently, the factors influencing outcome are mostly unknown. Studies have found a link between genetics and the risk of AF and efficacy of rhythm control. The aim of this study was to examine the association between eight single-nucleotide variants (SNVs) and the risk of AF development and recurrence after DCC. Materials and Methods: Regarding the occurrence of AF, 259 AF cases and 108 controls were studied. Genotypes for the eight SNVs located in the genes CAV1, MYH7, SOX5, KCNN3, ZFHX3, KCNJ5 and PITX2 were determined using high-resolution melting analysis and confirmed with Sanger sequencing. Six months after DCC, a telephone interview was conducted to determine whether AF had recurred. A polygenic risk score (PRS) was calculated as the unweighted sum of risk alleles. Multivariate regression analyses were performed to assess SNV and PRS association with AF occurrence and recurrence after DCC. Results: The risk allele of rs2200733 (PITX2) was significantly associated with the development of AF (p = 0.012, OR = 2.31, 95% CI = 1.206–4.423). AF recurred in 60% of patients and the allele generally associated with a decreased risk of AF of rs11047543 (SOX5) was associated with a greater risk of AF recurrence (p = 0.014, OR = 0.223, 95% CI = 0.067–0.738). A PRS of greater than 7 was significantly associated (p = 0.008) with a higher likelihood of developing AF after DCC (OR = 4.174, 95% CI = 1.454–11.980). Conclusions: A higher PRS is associated with increased odds of AF recurrence after treatment with DCC. PITX2 (rs2200733) is significantly associated with an increased risk of AF. The protective allele of rs11047543 (SOX5) is associated with a greater risk of AF recurrence. Further studies are needed to predict the success of rhythm control and guide patient selection towards the most efficacious treatment.

Rate and Rhythm Control Treatment in the Elderly and Very Elderly Patients With Atrial Fibrillation: An Observational Cohort Study of 1497 Patients

Stroke prevention and rate or rhythm control are crucial in the management of atrial fibrillation (AF). There is recent evidence for benefit of early rhythm control, yet rate control is the first choice in elderly patients. However, the efficacy and safety of rate and rhythm control in the elderly population remains largely unexplored. Therefore, we analyzed electronic health record data and investigated prescribing patterns and mortality of both strategies in elderly patients with AF. Data from patients with AF who were aged ≥75 years, used a pharmacological rate or rhythm control strategy, and visited Cardiology Centers of the Netherlands between 2007 and 2018 were extracted. Of the 1497 patients (54% female), 316 (21%) were prescribed rhythm control and 1181 (79%) rate control. Patients aged >85 years (OR: 2.28; 95% CI: 1.51-3.44, P< 0.001) and those with permanent AF (OR: 2.71; 95% CI: 1.67-4.41, P< 0.001) were more likely to receive rate control, whereas those with paroxysmal AF were less likely to receive rate control (OR: 0.42; 95% CI: 0.32-0.56, P< 0.001). After correction for relevant confounders, the mortality risk for patients using rhythm control and patients using rate control was similar (HR: 0.89; 95% CI: 0.70-1.12, P = 0.31). A more liberal approach towards prescribing a rhythm control strategy to the elderly patients with AF may be warranted and seems safe. Our data underscore the need for prospective studies to provide definite answers on efficacy and safety of rhythm control in elderly patients with AF.

Clinical utility of rhythm control by electrical cardioversion to assess the association between self-reported symptoms and rhythm status in patients with persistent atrial fibrillation

Background

The best strategy to assess the association between symptoms and rhythm status (symptom-rhythm correlation) in patients with atrial fibrillation (AF) remains unclear. We aimed to determine the clinical utility of rhythm control by electrical cardioversion (ECV) to assess symptom-rhythm correlation in patients with persistent AF.

Methods

We used ECV to examine symptom-rhythm correlation in 81 persistent AF patients. According to current clinical practice, the presence of self-reported symptoms before ECV and at the first outpatient clinic follow-up visit (within 1-month) was assessed to determine the prevalence of a symptom-rhythm correlation (defined as self-reported symptoms present during AF and absent in sinus rhythm or absent in AF and yet relief during sinus rhythm). In addition, we evaluated symptom patterns around ECV.

Results

Only in 18 patients (22%), a symptom-rhythm correlation could be documented. Twenty-eight patients (35%) did not show any symptom-rhythm correlation and 35 patients (43%) had an unevaluable symptom-rhythm correlation as these patients were in symptomatic AF both at baseline and at the first outpatient AF clinic follow-up visit. Importantly, self-reported symptom patterns around ECV were intra-individually variable in 10 patients (12%) without symptom-rhythm correlation (of which 9 patients (11%) had AF recurrence) and in 2 patients (2%) with an unevaluable symptom-rhythm correlation.

Conclusions

In patients with persistent AF, symptom assessment around rhythm control by ECV, once before ECV and once within 1-month follow-up, rarely identifies a symptom-rhythm correlation and often suggests changes in symptom pattern. Better strategies are needed to assess symptom-rhythm correlation in patients with persistent AF.

Estimation of the economic burden of atrial fibrillation-related stroke in Greece

Background: Stroke is aleading cause of death and disability, with atrial fibrillation (AF) being among key risk factors and AF-related stroke inflicting significant burden on healthcare systems and society. The present study was undertaken for estimating the total annual socioeconomic burden of AF-related stroke in Greece and identifying the key cost contributors.Research design and methods: A cost-of-illness model was developed for estimating the total annual economic burden of AF-related stroke in Greece, from asocietal perspective (year 2018). Atargeted literature review and an advisory board consisting of key experts in the management of AF and AF-related stroke were performed for collecting local resource use and epidemiological data.Results: The total annual socioeconomic burden of AF-related stroke was estimated at €175million, in 2018. Direct and indirect costs accounted for 59% and 41%, respectively. Main contributors were informal care (21.1%), patients' productivity losses (19.7%) and hospitalizations (15.0%), accounting for more than half of the total costs of AF-related stroke events.Conclusion: A F-related stroke imposes asignificant socioeconomic burden in Greece. Despite results relying on estimations, it seems that ensuring efficient reallocation of resources in appropriate prevention and early intervention strategies could decrease AF-related stroke's burden but also enhance healthcare systems' efficiency.Abbreviations: AF=atrial fibrillation.

A Web-Based Integrated Management Program for Improving Medication Adherence and Quality of Life, and Reducing Readmission in Patients With Atrial Fibrillation: Randomized Controlled Trial

BACKGROUND

Atrial fibrillation (AF) is related to a variety of chronic diseases and life-threatening complications. It is estimated that by 2050, there will be 72 million patients with AF in Asia, of which 2.9 million will have AF-associated stroke. AF has become a major issue for health care systems.

OBJECTIVE

We aimed to evaluate the effects of a web-based integrated management program on improving coping strategies, medication adherence, and health-related quality of life (HRQoL) in patients with AF, and to detect the effect on decreasing readmission events.

METHODS

The parallel-group, single-blind, prospective randomized controlled trial recruited patients with AF from a medical center in northern Taiwan and divided them randomly into intervention and control groups. Patients in the intervention group received the web-based integrated management program, whereas those in the control group received usual care. The measurement tools included the Brief Coping Orientation to Problems Experienced (COPE) scale, Medication Adherence Rating Scale (MARS), the three-level version of the EuroQoL five-dimension self-report questionnaire (EQ-5D-3L), and readmission events 2 years after initiating the intervention. Data were collected at 4 instances (baseline, 1 month, 3 months, and 6 months after initiating the intervention), and analyzed with generalized estimating equations (GEEs).

RESULTS

A total of 231 patients were recruited and allocated into an intervention (n=115) or control (n=116) group. The mean age of participants was 73.08 (SD 11.71) years. Most participants were diagnosed with paroxysmal AF (171/231, 74%), and the most frequent comorbidity was hypertension (162/231, 70.1%). Compared with the control group, the intervention group showed significantly greater improvement in approach coping strategies, medication adherence, and HRQoL at 1, 3, and 6 months (all P<.05). In addition, the intervention group showed significantly fewer readmission events within 2 years (OR 0.406, P=.03), compared with the control group.

CONCLUSIONS

The web-based integrated management program can significantly improve patients' coping strategy and medication adherence. Therefore, it can empower patients to maintain disease stability, which is a major factor in improving their HRQoL and reducing readmission events within 2 years.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04813094; https://clinicaltrials.gov/ct2/show/NCT04813094.

Association between Cardiovascular Health and Incident Atrial Fibrillation in the General Japanese Population Aged ≥40 Years

This study explores the association between lifestyle behavior and incident atrial fibrillation (AF) in the general Japanese population. Japanese residents aged ≥40 years undergoing a national health checkup in Kanazawa City were included. We hypothesized that better lifestyle behavior is associated with lower incidence of AF. Lifestyle behavior was evaluated by the total cardiovascular health (CVH) score (0 = poor to 14 = ideal), calculated as the sum of the individual scores on seven modifiable risk factors: smoking status, physical activity, obesity, patterns of eating schedule, blood pressure, total cholesterol, and blood glucose. The association between CVH and incident AF was assessed, adjusting for other factors. A total of 37,523 participants (mean age 72.3 ± 9.6 years, 36.8% men, and mean total CVH score 9 ± 1) were analyzed. During the median follow-up period of 5 years, 703 cases of incident AF were observed. Using a low CVH score as a reference, the upper group (ideal CVH group) had a significantly lower risk of incident AF (hazard ratio [HR] = 0.79, 95% confidence interval 0.65–0.96, p = 0.02), especially among those aged <75 years (HR = 0.68, 95% confidence interval 0.49–0.94, p = 0.02). Thus, ideal CVH is independently associated with a lower risk for incident AF, particularly in younger Japanese individuals (<75 years).

Determination of Parameters for an Entropy-Based Atrial Fibrillation Detector

Entropy algorithm is an important nonlinear method for cardiovascular disease detection due to its power in analyzing short-term time series. In previous a study, we proposed a new entropy-based atrial fibrillation (AF) detector, i.e., Entropy_AF, which showed a high classification accuracy in identifying AF and non-AF rhythms. As a variation of entropy measures, Entropy_AF has two parameters that need to be initialized before the calculation: (1) tolerance threshold r and (2) similarity weight n. In this study, a comprehensive analysis for the two parameters determination was presented, aiming to achieve a high detection accuracy for AF events. Data were from the MIT-BIH AF database. RR interval recordings were segmented using a 30-beat time window. The parameters r and n were initialized from a relatively small value, then gradually increased, and finally the best parameter combination was determined using grid searching. AUC (area under curve) values from the receiver operator characteristic curve (ROC) were compared under different parameter combinations of parameters r and n, and the results demonstrated that the selection of these two parameters plays an important role in AF/non-AF classification. Small values of parameters r and n can lead to a better detection accuracy than other selections. The best AUC value for AF detection was 98.15%, and the corresponding parameter combinations for Entropy_AF were as follows: r = 0.01, n = 0.0625, 0.125, 0.25, or 0.5; r = 0.05 and n = 0.0625, 0.125, or 0.25; and r = 0.10 and n = 0.0625 or 0.125.