Intermittent Atrial Fibrillation Research Articles

THU097 Primary Overproduction Of TSH Presenting As Intermittent Atrial Fibrillation Responding To Methimazole

Abstract Disclosure: T.D. Maher: None. Background: Intermittent Atrial Fibrillation (IAF) is commonly associated with Hyperthyroidism. TRH from the hypothalamus stimulates TSH production in the pituitary; a negative feedback loop of thyroxine to the hypothalamus is the primary regulator of TSH production. The Pituitary is adjacent to the sphenoid sinus; nasal and sinus inflammation and other factors may affect TSH production. With currently available thyroid tests it is a clinical challenge to be certain the thyroid is not contributing to IAF. Clinical Case: A 72-year-old male presented at age 57 (2007) with new onset IAF. The patient had Allergic Rhinitis since age 20. For IAF he was treated with Metoprolol, Flecanide and Dofenilide but IAF continued. On 3/2/11, TSH was 5.12 ((0.270-4.2 uU/Ml). At age 64 (2014), Catheter Ablation was performed. Before the Ablation, 08/16/2013, the FT4 was 1.2 (0.90-1.70) ng/ml and TSH 3.99 (0.270-4.200) uU/ml. Two years post Ablation, on 1/19/2016, TFTs were: FT4 1.10 (0.90-1.70) ng/ml; TSH 5.42 (0.270-4.200) uU/ml and repeat TFTs on 3/15/16 were: FT4 1.24 (0.90-1.70) ng/dl; TSH 4.10 (0.270-4.2 uU/dl. The diagnosis of Borderline Hypothyroid was entertained. He was trialed on Thyroxine 25 mcg daily with gradual increase to 75 mcg. The patient complained of being light headed, weak and having diffculty concentrating and the TSH was still elevated. Thyroxine was discontinued. In 2017, IAF returned. In October 2019 the thyroid was 35-40 Gm., firm, and with small nodules on palpation and ultrasound. The TFTs on 10/01/2019 were: FT4 0.81 (0.75-1.54) ng/ml and TSH 5.15 (0.3-4.2) uIU/ml. To test whether overproduction of TSH was causing excess Thyroxine release and IAF, low dose Methimazole was started at 5 mg, four days a week. There have been no episodes of AF for the past three years while on Methimazole. TFTs on 10/19/2022 were: FT4 0.94 (0.75-1.54) ng/ml and TSH 7.11 (0.099-4.2) uiU/m). Conclusion: In the clinical setting of IAF, elevated TSH and normal FT4, overproduction of TSH by extrinsic stimuli should be considered. Thyroid partial blockade with Methimazole is safe, economical, and reversible and may give valuable information about whether the thyroid is causing episodic Atrial Fibrillation. Presentation: Thursday, June 15, 2023

Diagnostic Evaluation of Stroke Etiology.

Precise therapies require precise diagnoses. This article provides an evidence-based approach to confirming the diagnosis of ischemic stroke, characterizing comorbidities that provide insights into the pathophysiologic mechanisms of stroke, and identifying targets for treatment to optimize the prevention of recurrent stroke. Identifying the presence of patent foramen ovale, intermittent atrial fibrillation, and unstable plaque is now routinely included in an increasingly nuanced workup in patients with stroke, even as ongoing trials seek to clarify the best approaches for treating these and other comorbidities. Multicenter trials have demonstrated the therapeutic utility of patent foramen ovale closure in select patients younger than age 60 years. Insertable cardiac monitors detect atrial fibrillation lasting more than 30 seconds in about one in ten patients monitored for 12 months following a stroke. MRI of carotid plaque can detect unstable plaque at risk of being a source of cerebral embolism. To optimize the prevention of recurrent stroke, it is important to consider pathologies of intracranial and extracranial blood vessels and of cardiac structure and rhythm as well as other inherited or systemic causes of stroke. Some aspects of the stroke workup should be done routinely, while other components will depend on the clinical circumstances and preliminary testing results.

A Smartwatch System for Continuous Monitoring of Atrial Fibrillation in Older Adults After Stroke or Transient Ischemic Attack: Application Design Study.

The prevalence of atrial fibrillation (AF) increases with age and can lead to stroke. Therefore, older adults may benefit the most from AF screening. However, older adult populations tend to lag more than younger groups in the adoption of, and comfort with, the use of mobile health (mHealth) apps. Furthermore, although mobile apps that can detect AF are available to the public, most are designed for intermittent AF detection and for younger users. No app designed for long-term AF monitoring has released detailed system design specifications that can handle large data collections, especially in this age group. This study aimed to design an innovative smartwatch-based AF monitoring mHealth solution in collaboration with older adult participants and clinicians. The Pulsewatch system is designed to link smartwatches and smartphone apps, a website for data verification, and user data organization on a cloud server. The smartwatch in the Pulsewatch system is designed to continuously monitor the pulse rate with embedded AF detection algorithms, and the smartphone in the Pulsewatch system is designed to serve as the data-transferring hub to the cloud storage server. We implemented the Pulsewatch system based on the functionality that patients and caregivers recommended. The user interfaces of the smartwatch and smartphone apps were specifically designed for older adults at risk for AF. We improved our Pulsewatch system based on feedback from focus groups consisting of patients with stroke and clinicians. The Pulsewatch system was used by the intervention group for up to 6 weeks in the 2 phases of our randomized clinical trial. At the conclusion of phase 1, 90 trial participants who had used the Pulsewatch app and smartwatch for 14 days completed a System Usability Scale to assess the usability of the Pulsewatch system; of 88 participants, 56 (64%) endorsed that the smartwatch app is "easy to use." For phases 1 and 2 of the study, we collected 9224.4 hours of smartwatch recordings from the participants. The longest recording streak in phase 2 was 21 days of consecutive recordings out of the 30 days of data collection. This is one of the first studies to provide a detailed design for a smartphone-smartwatch dyad for ambulatory AF monitoring. In this paper, we report on the system's usability and opportunities to increase the acceptability of mHealth solutions among older patients with cognitive impairment. ClinicalTrials.gov NCT03761394; https://www.clinicaltrials.gov/ct2/show/NCT03761394. RR2-10.1016/j.cvdhj.2021.07.002.

Dry textile electrode for ambulatory monitoring after catheter ablation of atrial fibrillation: A pilot study of simultaneous comparison to the Holter electrocardiogram

Background: Holter electrocardiogram (ECG) is the gold standard for ambulatory monitoring of atrial fibrillation (AF) but it is insufficient because of its limited recording time. Although several consumer ECG devices provide longer recording time, they generally do not undergo the regulatory process for medical use. Furthermore, current medical-grade devices for longer ECG monitoring are not continuous or too invasive for AF monitoring.A wearable ECG with a medical-grade dry textile electrode is a promising technology to remedy this limitation. This pilot study aimed to simultaneously compare the wearable and Holter ECGs for ambulatory monitoring in a clinical setting. Methods: This prospective observational study enrolled 18 patients who underwent AF ablation. One day after AF ablation, ambulatory ECG was obtained for three hours simultaneously using both the wearable and Holter ECG devices. Automatic ECG interpretations between devices were compared with correlation and agreement analyses. Results: Simultaneous ECG monitoring demonstrated a comparable analysis time and total heart beats between the two devices. Almost complete correlation and agreement were also demonstrated in all clinically relevant testing aspects except in R-wave amplitude (r = 0.743, p < .001). AF was detected in three patients. AF duration was the same in both ECG devices in two patients with continuous AF. In the remaining patient with intermittent AF, AF duration was shortened by 0.6% with the wearable ECG as compared to that with the Holter ECG. Conclusions: Simultaneous ECG comparison revealed a high consistency between the wearable and Holter ECG devices. The results of this study warrant further clinical studies for long-term monitoring of ambulatory ECG after AF ablation.

Het nut van implanteerbare looprecorders na een embolische beroerte van ongekende oorsprong

The use of implantable loop recorders after embolic stroke of undetermined source Unknown intermittent atrial fibrillation (AF) is a potential source of embolism in patients with embolic stroke of undetermined source (ESUS). Prolonged heart rhythm monitoring with implantable loop recorders (ILR) could increase the detection of AF. Patients with detected (subclinical) AF may benefit from a therapy with anticoagulants after ESUS. The authors of this article performed a retrospective analysis of patients who received an ILR after suspected ESUS at the University Hospitals of Leuven (Belgium) between April 2008 and March 2019. They describe the proportion of patients in whom AF was detected and studied the predictors of AF detection. With prolonged monitoring, the AF detection rate increased, mainly in the first 2 years after implantation. AF was detected in 28 out of 84 patients (33.3%) after a median follow-up of 8 months. Patients with AF were significantly older and tended to have more arterial hypertension. All patients with detected AF received oral anticoagulation. Although a 24-hour Holter monitoring and a week recorder were negative for AF detection, an ILR established (subclinical) AF in 1 out of 3 patients after ESUS.

Dry textile electrode for ambulatory monitoring after catheter ablation of atrial fibrillation: A pilot study of simultaneous comparison to the Holter electrocardiogram

Background: Holter electrocardiogram (ECG) is the gold standard for ambulatory monitoring of atrial fibrillation (AF) but it is insufficient because of its limited recording time. Although several consumer ECG devices provide longer recording time, they generally do not undergo the regulatory process for medical use. Furthermore, current medical-grade devices for longer ECG monitoring are not continuous or too invasive for AF monitoring. A wearable ECG with a medical-grade dry textile electrode is a promising technology to remedy this limitation. This pilot study aimed to simultaneously compare the wearable and Holter ECGs for ambulatory monitoring in a clinical setting. Methods: This prospective observational study enrolled 18 patients who underwent AF ablation. One day after AF ablation, ambulatory ECG was obtained for three hours simultaneously using both the wearable and Holter ECG devices. Automatic ECG interpretations between devices were compared with correlation and agreement analyses. Results: Simultaneous ECG monitoring demonstrated a comparable analysis time and total heart beats between the two devices. Almost complete correlation and agreement were also demonstrated in all clinically relevant testing aspects except in R-wave amplitude (r = 0.743, p < .001). AF was detected in three patients. AF duration was the same in both ECG devices in two patients with continuous AF. In the remaining patient with intermittent AF, AF duration was shortened by 0.6% with the wearable ECG as compared to that with the Holter ECG. Conclusions: Simultaneous ECG comparison revealed a high consistency between the wearable and Holter ECG devices. The results of this study warrant further clinical studies for long-term monitoring of ambulatory ECG after AF ablation.

The a’ velocity by tissue-Doppler echocardiography correlates to invasive mean left atrial pressure in patients with normal ejection fraction

Objectives To evaluate the correlation of a’ velocity by tissue-Doppler measurements with invasively measured mean left atrial pressure in patients with normal ejection fraction. Design In this retrospective study, we evaluated the septal a’, lateral a’ and average a’ velocity by tissue-Doppler echocardiography, in 125 in-hospital patients, 1–12 h before an elective pulmonary vein isolation due to intermittent atrial fibrillation, and compared to invasively measured mean left atrial pressure (LAP) during the invasive procedure. The patients, aged 35–81 years, had to be in sinus rhythm at both examinations, no atrial fibrillation during two procedures, no or mild valve disease and normal ejection fraction (>50%). Results Invasively measured mean LAP correlated well to septal a’ (r = −0.435), lateral a’ (r = −0.473) and average a’ velocity (r = −0.491). Normal mean LAP (≤12 mmHg) was found in 95 patients and elevated mean LAP (>12 mmHg) in 30 patients. The patients with elevated mean LAP had a lower septal a’ velocity (6.5 ± 2.7 vs 8.6 ± 2.3 cm/s; p < .01), lateral a’ velocity (5.9 ± 2.3 vs 8.6 ± 2.1 cm/s; p < .01) and average a’ velocity (6.2 ± 2.4 vs 8.8 ± 2.1 cm/s; p < .01) compared to patients with normal mean LAP. Septal a’, lateral a’ and average a’ velocity were good predictors of elevated mean LAP with AUC of 0.78, 0.83 and 0.82. Average a’ velocity with cut-off < 7.25 cm/s had a sensitivity of 83% and a specificity of 77% to predict elevated mean LAP. Conclusion The a’ velocity is a good indicator of mean LAP and might be considered in the evaluation of left ventricle filling pressure in patients with normal ejection fraction.

Dry textile electrode for ambulatory monitoring after catheter ablation of atrial fibrillation: A pilot study of simultaneous comparison to the Holter electrocardiogram.

Background: Holter electrocardiogram (ECG) is the gold standard for ambulatory monitoring of atrial fibrillation (AF) but it is insufficient because of its limited recording time. A wearable ECG with a medical-grade dry textile electrode is a promising technology to remedy this limitation. This pilot study aimed to simultaneously compare the wearable and Holter ECGs for ambulatory monitoring in a clinical setting. Methods: This prospective observational study enrolled 18 patients who underwent AF ablation. One day after AF ablation, ambulatory ECG was obtained for three hours simultaneously using both the wearable and Holter ECG devices. Automatic ECG interpretations between devices were compared with correlation and agreement analyses. Results: Simultaneous ECG monitoring demonstrated a comparable analysis time and total heart beats between the two devices. Almost complete correlation and agreement were also demonstrated in all clinically relevant testing aspects except in R-wave amplitude (r = 0.743, p < .001). AF was detected in three patients. AF duration was the same in both ECG devices in two patients with continuous AF. In the remaining patient with intermittent AF, AF duration was shortened by 0.6% with the wearable ECG as compared to that with the Holter ECG. Conclusions: Simultaneous ECG comparison revealed a high consistency between the wearable and Holter ECG devices. The results of this study warrant further clinical studies for long-term monitoring of ambulatory ECG after AF ablation.

Abstract 10763: Atrial Fibrillation and Supraventricular Ectopy in Relation to Brain Morphology and Subclinical Vascular Brain Injury: The Multi-Ethnic Study of Atherosclerosis

Introduction: Atrial fibrillation (AF) increases stroke risk and is associated with accelerated cognitive decline. Information is mixed about the relationship of AF and other supraventricular (SV) arrhythmias with brain changes on magnetic resonance imaging (MRI). Hypothesis: Prevalent AF and SV ectopy are associated with reduced gray matter (GM) volume and subclinical vascular brain injury. Methods: In the Multi-Ethnic Study of Atherosclerosis (MESA), participants completed Zio Patch monitoring and brain MRI. Prevalent AF was estimated from ambulatory monitoring, hospital surveillance, Medicare claims, and MESA electrocardiogram (ECG). For secondary analyses, AF was categorized into continuous - AF during 100% of monitoring - and intermittent - prevalent AF with &lt;100% AF during monitoring. Brain MRI measures included GM volume, white matter (WM) lesion volume, WM fractional anisotropy, and presence of cerebral microbleeds (CMBs). Linear and Poisson regression analyses were adjusted for cardiovascular risk factors and socioeconomic status. Results: In MESA, 967 participants without a history of stroke or transient ischemic attack (TIA) completed &gt;24 hours of ECG monitoring (median, 14.0 days) and completed brain MRI a median 17 months later. Mean (standard deviation) age was 72 (8) years; 53% were women. A total of 116 participants had prevalent AF, of whom 20 had continuous AF. Compared with no AF, prevalent AF was associated with lower WM FA (-0.22 standard deviations, 95% CI: -0.39, -0.04) and higher prevalence of CMBs (prevalence ratio: 1.46, 95% CI: 1.18, 1.80). In secondary analyses, compared with no AF, continuous but not intermittent AF was associated with lower GM volume (-18.6 mL, 95% CI: -31.4, -5.8). Rates of premature atrial contractions and runs of SV tachycardia were not significantly associated with brain MRI measures. Conclusions: In a multi-ethnic sample free of a history of stroke or TIA, prevalent AF was associated with lower WM FA, a measure of WM injury, and presence of CMBs. These results highlight the importance of AF prevention for brain health. Further analysis of subclinical infarcts is needed in this sample, and study in other settings is needed to confirm whether greater AF burden is associated with reduced GM volume.

B-IN01-07 AN ARTIFICIAL INTELLIGENCE-BASED MODEL FOR PREDICTION OF ATRIAL FIBRILLATION FROM SINGLE-LEAD SINUS RHYTHM ECGS ENABLING SCREENING

Screening for atrial fibrillation (AF) is currently recommended in the ESC guidelines. To identify individuals that might benefit most from screening, age cut-offs or addition of co-morbidity/biomarkers are often used. A machine-learning model could aid in identifying patterns in normal sinus rhythm ECGs that indicate high risk for having intermittent AF. The aim of this research project was to study if an artificial intelligence-based model could predict who would benefit from prolonged screening for AF using intermittent ECGs based on a single sinus rhythm one-lead ECG. A convolutional neural network model was trained and evaluated using data from three AF screening studies: STROKESTOP I, STROKESTOP II and SAFER. In all three studies, one-lead intermittent ECG was used for at least two weeks in order to detect AF. A total of 443,875 ECGs from 13,080 patients aged ≥65 years were included in the analysis. The training set consisted of 247,463 ECGs from 80% of participants in SAFER and STROKESTOP II. ECGs from the remaining 20% of participants in STROKESTOP II and SAFER and all ECGs from STROKESTOP I were included in the validation set for the model. The area under the ROC curve (AUC) was measured. Sensitivity was set to 75% and specificity was calculated. From a single time-point ECG the artificial intelligence-based algorithm predicted intermittent AF with an AUC of 0.68 (95% CI 0.67-0.70) and specificity of 48% (CI 48-49) in the whole validation set. In STROKESTOP I the algorithm predicted AF with an AUC of 0.64 (CI 0.62-0.66) and specificity of 43% (CI 40-46), and similarly in STROKESTOP II with an AUC of 0.63 (CI 0.60-0.66) and specificity of 40% (CI 35-46). Better results were seen in the SAFER study where the age distribution was wider, AUC 0.83 (CI 0.81-0.86) and specificity 76% (CI 67-82). An artificial intelligence-enabled network has the ability to predict future AF from a sinus rhythm single-lead ECG in an age homogenous group. In a screening program the algorithm may be used as an interim step to identify individuals that might benefit from screening. This would reduce the number of individuals requiring prolonged screening and increase feasibility.

Cataract operated by phacoemulsification in a patient with verticillata cornea - clinical case

Introduction: I will present the case of a patient treated for several years with amiodarone for intermittent atrial fibrillation, to which, through long use, corneal and lens changes have occurred, the latter age-induced.

Predictors of postoperative atrial fibrillation persisting beyond hospital discharge after coronary artery bypass grafting.

Minimal invasive extracorporeal circuits (MiECC) have been associated with a significant reduction in the incidence of postoperative atrial fibrillation (AF). Nevertheless, AF remains one of the most common complications following elective primary coronary artery bypass grafting (CABG). The aim of this study was to identify the predictors of AF persisting beyond the hospital stay in elective primary CABG patients. We conducted a retrospective analysis for the predictors of AF that persisted beyond discharge between all patients who received an elective isolated CABG in our institution between 2009 and 2014. Patients with a positive history for intermittent or persistent AF were excluded from the analysis. Almost all patients were discharged to a rehabilitation facility where they stayed for 3 to 4 weeks postoperatively. At rehab approximately 91% of them received Holter monitoring at least once prior to their discharge. A total of 770 patients were included in the analysis of which 763 patients survived the in-hospital stay. The incidence of AF at hospital discharge was 4.2% (32/763) while that on Holter monitor at Rehab was 1.5% (10/685). Age and the type of extracorporeal circuit (ECC) utilized were the only significant predictors for both AF at discharge (p < 0.01 both) and on Holter monitor in rehab (p < 0.01 and 0.02, respectively). This was also confirmed on multivariate analysis. Our findings show that the benefits of MiECC regarding the incidence of postoperative AF persist beyond hospital discharge. They may thus positively influence the outcomes of patients beyond the early postoperative period.

A Deep Learning Approach for Featureless Robust Quality Assessment of Intermittent Atrial Fibrillation Recordings from Portable and Wearable Devices.

Atrial fibrillation (AF) is the most common heart rhythm disturbance in clinical practice. It often starts with asymptomatic and very short episodes, which are extremely difficult to detect without long-term monitoring of the patient’s electrocardiogram (ECG). Although recent portable and wearable devices may become very useful in this context, they often record ECG signals strongly corrupted with noise and artifacts. This impairs automatized ulterior analyses that could only be conducted reliably through a previous stage of automatic identification of high-quality ECG intervals. So far, a variety of techniques for ECG quality assessment have been proposed, but poor performances have been reported on recordings from patients with AF. This work introduces a novel deep learning-based algorithm to robustly identify high-quality ECG segments within the challenging environment of single-lead recordings alternating sinus rhythm, AF episodes and other rhythms. The method is based on the high learning capability of a convolutional neural network, which has been trained with 2-D images obtained when turning ECG signals into wavelet scalograms. For its validation, almost 100,000 ECG segments from three different databases have been analyzed during 500 learning-testing iterations, thus involving more than 320,000 ECGs analyzed in total. The obtained results have revealed a discriminant ability to detect high-quality and discard low-quality ECG excerpts of about 93%, only misclassifying around 5% of clean AF segments as noisy ones. In addition, the method has also been able to deal with raw ECG recordings, without requiring signal preprocessing or feature extraction as previous stages. Consequently, it is particularly suitable for portable and wearable devices embedding, facilitating early detection of AF as well as other automatized diagnostic facilities by reliably providing high-quality ECG excerpts to further processing stages.

Discovery of lung cancer after an injury on holiday

Discovery of lung cancer after an injury on holiday

Effects of Genetic Variants on Stroke Risk.

Effects of Genetic Variants on Stroke Risk.

PMD20 COST EFFECTIVENESS ANALYSIS OF IMPLANTABLE CARDIAC MONITORS TO DETECT ATRIAL FIBRILLATION AFTER CRYPTOGENIC STROKE

Cryptogenic strokes (CS) are those with no known cause after standard diagnostic tests, but intermittent atrial fibrillation (AF) can be missed. Implantable cardiac monitors (ICMs) allow long-term monitoring for AF which, if identified, anticoagulants can be given to reduce secondary stroke risk. This study assessed the cost-effectiveness of ICMs compared with standard of care monitoring (SoC) for detecting AF after at least 24 hours of external ECG monitoring in CS patients. A two-stage de novo economic model was developed to assess the costs and benefits of ICMs compared with SoC. The first stage of the model was a short-term patient flow model to identify CS patients with AF who have been detected and are then prescribed anticoagulation treatment and those who are undetected and remain on antiplatelet treatment. The second stage of the model was a long-term Markov model which captures the lifetime costs and benefits of AF patients on either anticoagulation or antiplatelet treatment. Results of a clinical effectiveness systematic review identified one randomised controlled trial (CRYSTAL-AF) that provided data for an ICM compared with SoC and was used to populate the model. CRYSTAL-AF demonstrated that over 36 months, the ICM detected AF in 30% of patients compared with 3% in the SoC arm. The de novo economic model estimated the incremental cost of an ICM compared with SoC is £1,687 and the incremental quality adjusted life year (QALY) gain is 0.07, resulting in an incremental cost effectiveness ratio (ICER) of £24,875. The cost-effectiveness results indicate that ICMs could be considered a cost-effective use of NHS resources at a £20,000 – £30,000 threshold compared with SoC for patients who have had a CS and no AF has been detected after at least 24 hours of external ECG monitoring.

Prevalence and Characteristics of Subclinical Atrial Fibrillation in a Community-Dwelling Elderly Population: The ARIC Study.

The prevalence of subclinical atrial fibrillation (AF) in the elderly general population is unclear. We sought to define the prevalence of subclinical AF in a community-based elderly population and to characterize subclinical AF and the incremental diagnostic yield of 4 versus 2 weeks of continuous ECG monitoring. We conducted a cross-sectional analysis within the community-based multicenter observational ARIC study (Atherosclerosis Risk in Communities) using visit 6 (2016-2017) data. The 2616 ARIC study participants who wore a leadless, ambulatory ECG monitor (Zio XT Patch) for up to 2 weeks were aged 79±5 years, 42% men, and 26% black. In a subset, 386 participants without clinically recognized AF wore the monitor twice, each time for up to 2 weeks. We characterized the prevalence of subclinical AF (ie, AF detected on the Zio XT Patch without clinically recognized AF) over 2 weeks of monitoring and the diagnostic yield of 4 versus 2 weeks of monitoring. The prevalence of subclinical AF was 2.5%; the prevalence of subclinical AF was 3.3% among white men, 2.5% among white women, 2.1% among black men, and 1.6% among black women. Subclinical AF was mostly intermittent (75%). Among those with intermittent subclinical AF, 91% had AF burden ≤10% during the monitoring period. In a subset of 386 participants without clinical AF, 78% more subclinical AF was detected by 4 weeks versus 2 weeks of ECG monitoring. In our study, the prevalence of subclinical AF was lower than previously reported and monitoring beyond 2 weeks provided substantial incremental diagnostic yield. Future studies should focus on individuals with higher risk to increase diagnostic yield and consider continuous monitoring duration longer than 2 weeks.

Lifetime Pattern of Atrial Fibrillation and the Risks of Stroke and Death in a Population-based Cohort of Men (from The Manitoba Follow-Up Study)

Atrial fibrillation (AF) is associated with stroke and mortality. The arrhythmia can be sustained or intermittent. Previous studies that have used fixed covariates and short-time horizons to examine the relation between the pattern of AF and the occurrence of events have produced conflicting results. The Manitoba Follow-Up Study includes 3,983 originally healthy men who have been followed with routine examinations since 1948. AF status during each visit was classified into the following patterns: free of AF, newly diagnosed; intermittent AF-in sinus;intermittent AF-in AF; sustained AF. We created adjusted Cox proportional hazards models with time-dependent covariates to estimate risks for stroke and death according to AF pattern. After 167,982 person-years of follow-up and 66,297 electrocardiograms (ECGs), 548 men had at least 1 ECG documenting AF, 799 had a stroke, and 3173 died. Relative to men free of AF, sustained and newly diagnosed AF were associated with stroke (hazard ratio [HR] 1.85, 95% confidence interval [CI] 1.33 to 2.59 and HR 1.71, 95% CI 1.10 to 2.66, respectively) and death (HR 2.48, 95% CI 2.11 to 2.92 and HR 2.03, 95% CI 1.64 to 2.52, respectively). Intermittent AF was associated with death (HR 2.41 95% CI 1.58 to 3.68 in AF and HR 1.71 95% CI 1.44 to 2.03 in sinus), but not with stroke (HR 0.68, 95% CI 0.22 to 2.13 in AF and HR 1.02 95% CI 0.72 to 1.45 in sinus). Antithrombotic therapy was associated with a reduced risk of the outcomes. In conclusion, longitudinal analysis of patterns of AF evolving over time provided evidence that the associated risks of stroke and death vary considerably with rhythm classification on serial ECGs.

Comparison between electrocardiogram- and photoplethysmogram-derived features for atrial fibrillation detection in free-living conditions

Objective: Atrial fibrillation (AF) is the most commonly experienced arrhythmia and it increases the risk of stroke and heart failure. The challenge in detecting the presence of AF is the occasional and asymptomatic manifestation of the condition. Long-term monitoring can increase the sensitivity of detecting intermittent AF episodes, however it is either cumbersome or invasive and costly with electrocardiography (ECG). Photoplethysmography (PPG) is an unobtrusive measuring modality enabling heart rate monitoring, and promising results have been presented in detecting AF. However, there is still limited knowledge about the applicability of the PPG solutions in free-living conditions. The aim of this study was to compare the inter-beat interval derived features for AF detection between ECG and wrist-worn PPG in daily life. Approach: The data consisted of 24 h ECG, PPG, and accelerometer measurements from 27 patients (eight AF, 19 non-AF). In total, seven features (Shannon entropy, root mean square of successive differences (RMSSD), normalized RMSSD, pNN40, pNN70, sample entropy, and coefficient of sample entropy (CosEn)) were compared. Body movement was measured with the accelerometer and used with three different thresholds to exclude PPG segments affected by movement. Main results: CosEn resulted as the best performing feature from ECG with Cohens kappa 0.95. When the strictest movement threshold was applied, the same performance was obtained with PPG (kappa = 0.96). In addition, pNN40 and pNN70 reached similar results with the same threshold (kappa = 0.95 and 0.94), but were more robust with respect to movement artefacts. The coverage of PPG was 24.0%–57.6% depending on the movement threshold compared to 92.1% of ECG. Significance: The inter-beat interval features derived from PPG are equivalent to the ones from ECG for AF detection. Movement artefacts substantially worsen PPG-based AF monitoring in free-living conditions, therefore monitoring coverage needs to be carefully selected. Wrist-worn PPG still provides a promising technology for long-term AF monitoring.

Development of Heart Failure From Transient Atrial Fibrillation Attacks inResponders to Cardiac Resynchronization Therapy.

This study aimed to clarify the clinical impact of transient atrial fibrillation (AF) attacks themselves and the efficacy of cardiac resynchronization therapy (CRT) in patients with intermittent AF. The benefit of CRT in patients with intermittent AF, especially the effect of the AF attacks themselves, remains unclear. Among our cohort of 269 consecutive CRT patients, we compared the percent of biventricular pacing (BIVP%) and other clinical characteristics between patients with intermittent AF and those with sinus rhythm (SR). During a median follow-up of 942 days (interquartile range: 379 to 1,464 days) a total of 22 patients, including 59% of CRT responders, developed heart failure (HF) due to a transient AF attack itself, and that accounted for 21% of all HF events. The BIVP% during the AF attacks was significantly lower than that during SR (p< 0.05). When compared to the SR groups, patients with intermittent AF had a significantly higher risk of developing HF or death (hazard ratio: 2.2; 95% confidence interval: 1.3 to 3.8). However, the patients who received a BIVP% of≥90% during AF attacks were comparable to those with SR (hazard ratio: 1.2; 95% confidence interval: 0.4 to 3.0). A substantial number of patients developed HF due to transient AF attacks themselves even in the CRT responders, and the reason was mainly due to the loss of the BIVP%.