Continuous Atrial Fibrillation Research Articles

Quantitative 3D electron microscopy characterization of mitochondrial structure, mitophagy, and organelle interactions in murine atrial fibrillation

Atrial fibrillation (AF) is the most common clinical arrhythmia, however there is limited understanding of its pathophysiology including the cellular and ultrastructural changes rendered by the irregular rhythm, which limits pharmacological therapy development. Prior work has demonstrated the importance of reactive oxygen species (ROS) and mitochondrial dysfunction in the development of AF. Mitochondrial structure, interactions with other organelles such as sarcoplasmic reticulum (SR) and T-tubules (TT), and degradation of dysfunctional mitochondria via mitophagy are important processes to understand ultrastructural changes due to AF. However, most analysis of mitochondrial structure and interactome in AF has been limited to two-dimensional (2D) modalities such as transmission electron microscopy (EM), which does not fully visualize the morphological evolution of the mitochondria during mitophagy. Herein, we utilize focused ion beam-scanning electron microscopy (FIB-SEM) and perform reconstruction of three-dimensional (3D) EM from murine left atrial samples and measure the interactions of mitochondria with SR and TT. We developed a novel 3D quantitative analysis of FIB-SEM in a murine model of AF to quantify mitophagy stage, mitophagosome size in cardiomyocytes, and mitochondrial structural remodeling when compared with control mice. We show that in our murine model of spontaneous and continuous AF due to persistent late sodium current, left atrial cardiomyocytes have heterogenous mitochondria, with a significant number which are enlarged with increased elongation and structural complexity. Mitophagosomes in AF cardiomyocytes are located at Z-lines where they neighbor large, elongated mitochondria. Mitochondria in AF cardiomyocytes show increased organelle interaction, with 5X greater contact area with SR and are 4X as likely to interact with TT when compared to control. We show that mitophagy in AF cardiomyocytes involves 2.5X larger mitophagosomes that carry increased organelle contents. In conclusion, when oxidative stress overcomes compensatory mechanisms, mitophagy in AF faces a challenge of degrading bulky complex mitochondria, which may result in increased SR and TT contacts, perhaps allowing for mitochondrial Ca2+ maintenance and antioxidant production.

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

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

Effects of long-term continuous screening for atrial fibrillation on heart failure events - results from the randomized LOOP Study

Abstract Background Previous research established a solid link between atrial fibrillation (AF) and heart failure (HF). However, while two landmark trials have assessed AF screening for stroke prevention, the potential impact of AF screening on HF remains unclear. Purpose This secondary analysis of the LOOP Study aimed to investigate the effects of AF screening on HF events. Methods The LOOP Study was a randomized clinical trial evaluating long-term continuous AF screening with implantable loop recorder (ILR) in individuals aged 70-90 years and with ≥1 of arterial hypertension, diabetes mellitus, HF, and/or prior stroke. At inclusion, study participants were randomized 1:3 to either ILR screening or usual care. Anticoagulation was recommended upon AF detection, whereas other treatment was left to the discretion of the treating physician. In this secondary analysis, a cause-specific Cox regression model was applied to explore the effects of AF screening vs usual care on 1) time-to-first HF event and 2) total HF events, with the latter performed using the Andersen-and-Gill extension. HF event was defined as newly diagnosed HF with left ventricular ejection fraction ≤40% or any HF hospitalization in participants with prior diagnosis of HF with reduced ejection fraction. Results In total, 6004 participants were enrolled in the LOOP Study: 1501 in the ILR group vs 4503 in the Control group. The study population had a mean age of 75 years and slightly more males than females (53% vs 47%), whereas 266 (4.4%) were previously diagnosed with HF at baseline. During a median follow-up of 5.4 years, a total of 208 HF events were reported in 175 (2.9%) participants: 37 events among 34 (2.3%) participants in the ILR group vs 171 events among 141 (3.1%) participants in the Control group. For time-to-first HF event, the annualized event rate was 0.44%/year [95% confidence interval (CI): 0.30-0.62] vs 0.61%/year [95% CI: 0.51-0.72] for ILR vs Control, corresponding to a hazard ratio (HR) of 0.72 [95% CI: 0.50-1.05]. When assessing total HF events, a significantly lower event rate was observed in the ILR group (0.47%/year [95% CI: 0.33-0.65]) compared with the Control group (0.73%/year [95% CI: 0.62-0.84]), resulting in a HR of 0.65 [95% CI: 0.44-0.97]. Conclusions Among elderly individuals with additional stroke risk factors, long-term continuous AF screening led to a significantly reduced risk of total HF events, compared with usual care. This should be considered as hypothesis-generating and warrants further investigation.Cumulative incidence of HF event

Learning From Alarms: A Robust Learning Approach for Accurate Photoplethysmography-Based Atrial Fibrillation Detection Using Eight Million Samples Labeled With Imprecise Arrhythmia Alarms.

Atrial fibrillation (AF) is a common cardiac arrhythmia with serious health consequences if not detected and treated early. Detecting AF using wearable devices with photoplethysmography (PPG) sensors and deep neural networks has demonstrated some success using proprietary algorithms in commercial solutions. However, to improve continuous AF detection in ambulatory settings towards a population-wide screening use case, we face several challenges, one of which is the lack of large-scale labeled training data. To address this challenge, we propose to leverage AF alarms from bedside patient monitors to label concurrent PPG signals, resulting in the largest PPG-AF dataset so far (8.5 M 30-second records from 24,100 patients) and demonstrating a practical approach to build large labeled PPG datasets. Furthermore, we recognize that the AF labels thus obtained contain errors because of false AF alarms generated from imperfect built-in algorithms from bedside monitors. Dealing with label noise with unknown distribution characteristics in this case requires advanced algorithms. We, therefore, introduce and open-source a novel loss design, the cluster membership consistency (CMC) loss, to mitigate label errors. By comparing CMC with state-of-the-art methods selected from a noisy label competition, we demonstrate its superiority in handling label noise in PPG data, resilience to poor-quality signals, and computational efficiency.

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

BackgroundContinuous 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. ObjectivesThis 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. MethodsWe 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. ResultsThe 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). ConclusionsDNNs perform at least as well as SP models, classify more data, and thus may be better for continuous PPG monitoring.

Surgical ablation of long-standing persistent atrial fibrillation: 1-year outcomes from the CArdioSurgEry Atrial Fibrillation (CASE-AF) registry.

The CArdioSurgEry Atrial Fibrillation (CASE-AF) registry is a prospective, multicentre study for collecting and analysing real-world data of surgical atrial fibrillation (AF) treatment. This study aimed to evaluate outcomes of surgery for long-standing persistent AF at 1 year. In total, 17 centres consecutively include all eligible patients with continuous AF lasting for ≥1 year. Exclusion criteria are missing informed consent or age <18 years. For patient-reported outcomes measures, the European Heart Rhythm Association score was used. No presence of AF (based on ECG findings including Holter ECG and/or implanted devices), no re-ablation, no further cardioversion and no rehospitalization due to AF after a 3-month blanking period defined no AF recurrence at 1 year. From January 2017 to January 2020, a total of 1115 patients were enrolled in CASE-AF. Of them, 202 patients (mean age 69.7 ± 7.8 years, 27.2% female) underwent surgical ablation of long-standing persistent AF (study cohort), mostly accompanied by left atrial appendage closure (n = 180 [89%], resection n = 75 [42%]) and predominantly performed as concomitant (n = 174 [86%]) and left atrial only procedure (n = 144 [71%]). Early mortality (30 days) was 2.0% and morbidity was low. At follow-up (median 14.4 months, interquartile range, 12.7-17.6 months, 100% complete), 106 patients (56%) had no AF recurrence and 93% of them were asymptomatic. AF recurrence was accompanied by AF-related rehospitalization (n = 12, P = 0.003), direct current shock cardioversion (n = 23, P < 0.001), AF ablation (n = 7, P = 0.003) and stroke (n = 3, P = 0.059). Multivariable analysis identified cryoablation, predominantly performed endocardially including additional left atrial (74%) and biatrial (42%) lesions, as a significant factor for freedom from AF recurrence (odds ratio 2.7, 95% confidence interval 1.07-6.79, P = 0.035). According to CASE-AF, surgical ablation of long-standing persistent AF is most effective when concomitantly performed using endocardial cryoablation. Ongoing follow-up allows further elucidation of efficacious treatment strategies.

Acute mitral isthmus block during catheter ablation with vein of Marshall ethanol infusion: Angiographic considerations

Achieving bidirectional mitral isthmus block is still challenging. Conventional ablation methods involve radiofrequency applications on the endocardial aspect of the lateral mitral isthmus, and often epicardial applications inside the coronary sinus. To evaluate the impact of the systematic use of ethanol infusion in the vein of Marshall on the achievement of acute mitral isthmus block of additional epicardial component lesion. We evaluated patients referred to two centres for long-standing persistent atrial fibrillation ablation or recurrent peri-mitral flutter. All patients had pulmonary vein isolation and mitral isthmus line using ethanol infusion in the vein of Marshall for the first procedure and additional radiofrequency ablation lesion if necessary. For redo procedures, additional ablations (atrial lines and complex fractionated atrial electrogram ablations, if needed) were also performed. We included 149 patients, and ethanol infusion in the vein of Marshall was not performed in 27 patients (18%). Among 122 patients, 115 had long-standing persistent atrial fibrillation (94.2%) and seven had peri-mitral flutter (5.8%). The mean duration of continuous atrial fibrillation was 53 months before ablation. Acute bidirectional mitral isthmus block was obtained in 115 (94.2%) of the 122 patients who received ethanol infusion in the vein of Marshall (77% when considering the total population). The mean radiofrequency delivery time to obtain mitral isthmus block was 2.6minutes for the endocardial mitral isthmus radiofrequency ablation and 2.6minutes for the epicardial mitral isthmus radiofrequency ablation. Failure to obtain mitral isthmus block was associated with increased mitral isthmus length and left atrial dilation. No major complications related to ethanol infusion in the vein of Marshall were observed. Ethanol infusion in the vein of Marshall, when feasible (82%), was a safe approach to obtaining a high success rate (94%) of acute bidirectional endocardial and epicardial mitral isthmus block.

Electrocardiographic Morphology-Voltage-P-Wave-Duration (MVP) Score to Select Patients for Continuous Atrial Fibrillation Screening to Prevent Stroke

Morphology-voltage-P-wave-duration (MVP) score combining P-wave duration (PWD), P-wave voltage in lead I (PWVI), and interatrial block (IAB) has been demonstrated to predict atrial fibrillation (AF). Therefore, this study aimed to examine MVP score and its P-wave components as potential predictors of AF screening effects on stroke prevention. This was a secondary analysis of the LOOP Study (Atrial Fibrillation detected by Continuous ECG Monitoring using Implantable Loop Recorder to prevent Stroke in High-risk Individuals) which randomized older persons (aged 70 to 90years) with additional stroke risk factors to either continuous monitoring with implantable loop recorder and anticoagulation upon detection of AF episodes ≥6minutes (the intervention group), or usual care. A total of 5,759 participants were included in the present analysis, where PWD, PWVI, and IAB were determined through a computerized analysis of 12-lead electrocardiogram and further employed to calculate baseline MVP score (0 to 6) for each participant. In total, 305 (5.3%) had stroke or systemic embolism during follow-up, with a higher risk in the group with MVP score 5 to 6 than those having score 0 to 2 (hazard ratio (HR) 1.54 [95% confidence interval (CI) 1.01 to 2.35]). This risk increase was mainly upheld by participants with IAB (HR 1.62 [95% CI 1.11 to 2.36] for IAB vs no IAB) and with longer PWD (HR 1.37 [95% CI 1.07 to 1.75] for >110 vs ≤110ms). Compared with usual care, implantable loop recorder screening did not significantly reduce the risk of stroke or systemic embolism in any MVP risk categories (HR 0.80 [95% CI 0.60 to 1.08] for MVP score 0 to 2, 0.54 [95% CI 0.16 to 1.85] for MVP score 3 to 4, and 0.89 [95% CI 0.35 to 2.25] for MVP score 5 to 6; pinteraction=0.78). In conclusion, a higher MVP score was associated with an increased stroke risk, but it did not demonstrate an association with effects of AF screening on stroke prevention. These findings should be considered hypothesis-generating and warrant further study.

Atrial fibrillation screening to prevent stroke in patients with high NT-proBNP - a post-hoc analysis of the randomized LOOP study

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Innovation Fund Denmark Background and aims Stroke is a leading cause of mortality and disability, and atrial fibrillation (AF) is an important and potentially modifiable risk factor for stroke. AF screening can substantially increase the amount of patients diagnosed and treated, but randomized trials have yet to demonstrate a significant decrease in strokes following screening. N-terminal prohormone of brain natriuretic peptide (proBNP) is an established biomarker for AF and could potentially be used to select patients for screening. We a used randomized trial of AF screening vs usual care to investigated the usefulness of proBNP as a tool to select patients for screening to prevent outcomes. Methods The LOOP Study randomized AF-naïve individuals aged &amp;gt;70 years with additional stroke risk factors in a 1:3 ratio to either continuous AF screening using implantable loop recorder (ILR) with initiation of anticoagulation upon detection of AF, or usual care. In this post-hoc analysis, study participants with a baseline measurement of proBNP were included, and the effect of screening vs usual care was compared in groups according to proBNP tertiles. Results Of 6004 participants randomized, 5819 (97%) had proBNP measured. The tertiles of proBNP were at &amp;lt;11, 11-22, and 22 pmol/L (Figure 1). A total of 1014 participants (17.4%) were diagnosed with AF (ILR 32.1% vs Control 12.5%), and 310 (5.3%) endured a stroke or systemic arterial embolism (SAE) (ILR 4.5% vs Control 5.6%). In the lower two tertiles of proBNP, 13% were diagnosed with AF (ILR 26.6% vs Control 8.3%), and 4.6% endured a stroke or SAE (ILR 4.6% vs Control 4.6%), whereas in the highest tertile of proBNP, 25.9% were diagnosed with AF (ILR 42.9% vs 20.3%), and 6.73% endured a stroke or SAE (ILR 4.4% vs Control 7.5%). In the lower two tertiles of proBNP, there was no protective effect from AF screening as compared with usual care (hazard ratio (HR) 1.00 (95% CI 0.71-1.41), p=0.999), whereas in the highest tertile of proBNP there was a significant effect of screening (HR 0.59 (95% CI 0.37-0.93), p=0.021) (Figure 2). More details including proBNP cutoffs, and the impact on stroke subtypes, disability and mortality will be presented at the Congress. Conclusions In a population at increased risk of stroke, proBNP pose a useful biomarker to select individuals for AF screening to prevent stroke. In persons with increased proBNP, the effect of screening could be significant, whereas there is no signal towards effects from screening in people with normal proBNP levels.

Morphology-Voltage-P-wave-duration (MVP) score to select patients for continuous atrial fibrillation screening to prevent stroke

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The LOOP Study was funded by Innovation Fund Denmark [grant number 12-1352259], The Research Foundation for the Capital Region of Denmark, The Danish Heart Foundation [grant number 11-04-R83-A3363-22625], Aalborg University Talent Management Program, Arvid Nilssons Fond, Skibsreder Per Henriksen, R og Hustrus Fond, the European Union’s Horizon 2020 program [grant number 847770], Læge Sophus Carl Emil Friis og hustru Olga Doris Friis’ Legat, and an unrestricted grant from Medtronic. Background It is well known that atrial fibrillation (AF) confers a substantially increased risk of ischemic stroke, but data on health benefits from AF screening are scarce. The newly proposed MVP risk score combining the duration, voltage and morphology of P-wave has been demonstrated to be predictive of AF and might therefore also be useful in risk-stratifying individuals for AF screening and subsequent treatment. Purpose The present study sought to examine MVP risk score and its P-wave components for prediction of AF screening effects. Methods The LOOP Study randomized AF-naïve individuals aged 70-90 years with additional stroke risk factors to either continuous AF screening with implantable loop recorder (ILR) and subsequent anticoagulation initiation upon detection of AF episode ≥6 minutes, or usual care. In this secondary analysis, the LOOP participants with a baseline 12-lead electrocardiogram (ECG) suitable for P-wave measurement were included. Results Of 5759 participants included, 265 (4.6%) had had ischemic stroke during follow-up: 213 (4.9%) of 4311 in the control group versus 64 (3.6%) of 1448 in the ILR group. Among the participants in the control group, a significantly increased risk of ischemic stroke was observed for MVP score 5-6 versus score 0-2 (hazard ratio (HR) 1.66 [95% confidence interval (CI): 1.01-2.75]) and for the presence of interatrial block (IAB) versus no IAB (HR 1.85 [95% CI: 1.19-2.86]), whereas a P-wave voltage in lead I (PWVI) &amp;lt;100 µV was associated with risk reduction compared to higher voltage (HR 0.65 [95% CI: 0.45-0.93]). Further spline analysis revealed longer P-wave duration (PWD) to also be correlated with higher stroke risk (HR 1.49 [95% CI: 1.11-2.00] for &amp;gt;110 versus ≤110 ms). Compared with usual care, ILR screening did not significantly reduce the stroke risk regardless of MVP risk score, PWD, PWVI, or IAB pattern at baseline. Conclusions In an elderly population with additional stroke risk factors, both the P-wave parameters and the combined MVP risk score based on 12-lead ECG were associated with ischemic stroke, but these did not successfully demonstrate an association with effects of AF screening on stroke prevention.

Association of pericoronary adipose tissue with atrial fibrillation recurrence after ablation based on computed tomographic angiography.

Quantitative measurement of pericoronary adipose tissue volume (PCATV) and fat attenuation index (FAI) has mostly been used in the study of coronary artery related diseases but rarely in the relationship with atrial fibrillation (AF). This study was conducted to investigate the correlation of PCATV and FAI with the AF recurrence after ablation and the clinical significance. Patients with continuous AF who underwent radiofrequency ablation and computed tomographic angiography (CTA) were retrospectively enrolled. The PCATV, FAI, epicardial adipose tissue volume (EATV) and EAT density (EATD) arround the three main branches of the coronary arteries (LAD, LCX, and RCA) were measured quantitatively with cardiac function software and analyzed. 189 patients with continuous AF who underwent radiofrequency ablation for the first time were enrolled. After 12-month follow-up with a mean follow-up time of 10.93 ± 0.16months, 47 (24.9%) patients were confirmed to have AF recurrence. The 3V-FAI (-81.17 ± 4.27 vs. -83.31 ± 4.59 HU, P = 0.005), LCX-FAI (median -77 vs. median -81HU, P < 0.001), EATV (median 141.14vs. median 125.39ml, P = 0.010), and EATVI (median 70.77 vs. 66.73ml/m2, P = 0.008) were significantly increased in the recurrence group. EATVI (OR 1.043, 95% CI 1.020-1.066) and LCX-FAI (OR 1.254, 95% CI 1.145-1.374) were two significant independent risk factors for AF recurrence. In the comparison of ROC, the predictive value of LCX-FAI (cut-off value of >-81.5 HU, area under the curve (AUC) of 0.722) was higher than that of EATVI (cut-off value > 81.07ml/m2, AUC of 0.630). EATVI and LCX-FAI were related to recurrence of AF after ablation and have important clinical value in predicting the AF recurrence.

New atrial arrhythmia occurrence in single chamber implantable cardioverter defibrillator patients: A real-world investigation.

A current limitation of single chamber implantable cardioverter defibrillators (ICDs) is the lack of an atrial lead to reliably detect atrial fibrillation (AF) episodes. A novel ventricular based atrial fibrillation (VBAF) detection algorithm was created for single chamber ICDs to assess R-R variability for detection of AF. Patients implanted with Visia AF™ ICDs were prospectively enrolled in the Medtronic Product Surveillance Registry from December 15, 2015 to January 23, 2019 and followed with at least 30 days of monitoring with the algorithm. Time to device-detected daily burden of AF ≥ 6 min, ≥6 h, and ≥23 h were reported. Clinical actions after device-detected AF were recorded. A total of 291 patients were enrolled with a mean follow-up of 22.5 ± 7.9 months. Of these, 212 (73%) had no prior history of AF at device implant. However, 38% of these individuals had AF detected with the VBAF algorithm with daily burden of ≥6 min within two years of implant. In these 80 patients with newly detected AF by their ICD, 23 (29%) had a confirmed clinical diagnosis of AF by their provider. Of patients with a clinical diagnosis of AF, nine (39%) were newly placed on anticoagulation, including five of five (100%) patients having a burden >23 h. Continuous AF monitoring with the new VBAF algorithm permits early identification and actionable treatment for patients with undiagnosed AF that may improve patient outcomes.

The Impact of Statins on Postdischarge Atrial Fibrillation After Cardiac Surgery: Secondary Analysis from a Randomized Trial

BackgroundWhether statins reliably reduce the risk of postoperative atrial fibrillation (POAF) in patients undergoing cardiac surgery remains controversial. We sought to determine the impact of statin use on new-onset postdischarge POAF in the Post-Surgical Enhanced Monitoring for Cardiac Arrhythmias and Atrial Fibrillation (SEARCH-AF) CardioLink-1 randomized controlled trial. MethodsWe randomized 336 patients with risk factors for stroke (CHA2DS2-VASc score ≥ 2) and no history of preoperative atrial fibrillation (AF) to 30-day continuous cardiac rhythm monitoring after discharge from cardiac surgery with a wearable, patched-based device or to usual care. The primary endpoint was the occurrence of cumulative AF and/or atrial flutter lasting for ≥ 6 minutes detected by continuous monitoring, or AF and/or atrial flutter documented by a 12-lead electrocardiogram within 30 days of randomization. ResultsThe 260 patients (77.4%) discharged on statins were more likely to be male (P = 0.018) and to have lower CHA2DS2-VASc scores (P = 0.011). Patients treated with statins at discharge had a 2-fold lower rate of POAF than those who were not treated with statins in the entire cohort (18.4% vs 8.1%, log-rank P = 0.0076). On multivariable Cox regression including the CHA2DS2-VASc score adjustment, statin use was associated with a lower risk of POAF (hazard ratio 0.43, 95% confidence interval: 0.25-0.98, P = 0.043). Use of statins at a higher intensity was associated with lower risk of POAF, suggestive of a dose–response effect (log-rank Ptrend = 0.0082). ConclusionsThe use of statins was associated with a reduction in postdischarge POAF risk among patients undergoing cardiac surgery. The routine use of high-intensity statin to prevent subacute POAF after discharge deserves further study.

Left atrial appendage morphology with the progression of atrial fibrillation.

Left atrial appendage (LAA) size is crucial for determining the indication of transcatheter LAA closure. The aim of this study was to evaluate the differences in LAA morphology according to the types of atrial fibrillation (AF). A total of 299 patients (mean age: 67 ± 13 years) who underwent transesophageal echocardiography (TEE) were included. Patients were classified into non-AF (n = 64), paroxysmal AF (n = 86), persistent AF (n = 87), or long-standing persistent AF (n = 62). LAA morphology, including LAA ostial diameter and depth, was assessed using TEE. Patients with long-standing persistent AF had larger LAA ostial diameter and depth and lower LAA flow velocity. The maximum LAA ostial diameter was 19 ± 4 mm in patients with non-AF, 21 ± 4 mm in patients with paroxysmal AF, 23 ± 5 mm in patients with persistent AF, and 26 ± 5 mm in patients with long-standing persistent AF. LAA ostial diameter was increased by 2 or 3 mm with the progression of AF. LAA ostial diameter was correlated with LA volume index (R = 0.37, P < 0.01) and the duration of continuous AF (R = 0.30, P < 0.01), but not with age or the period from the onset of AF. In conclusion, LAA size was increased with the progression of AF.

Insights From Simultaneous Left and Right Atrial Septal Mapping in Patients With Persistent Atrial Fibrillation.

The interatrial septum (IAS) is thought to be involved in the mechanism of persistent atrial fibrillation (PeAF). Simultaneous contact mapping of both sides of the IAS has not been performed previously. The purpose of this study was to describe wave front (WF) activation patterns and extent of left and right atrial septal electrical dissociation in patients with PeAF. Simultaneous mapping of both atrial septal surfaces using 2 high-density grid catheters was performed. Filtered electrograms of continuous atrial fibrillation, sinus rhythm (SR), and atrial pacing recordings were exported to MATLAB for off-line phase/activation analysis, and activation patterns on paired surfaces were analyzed. WF activation patterns between the 2 grids were evaluated to determine whether activation WFs were associated or dissociated. Eight patients with PeAF undergoing catheter ablation were included. Complete dissociation of WF activation patterns between the 2 sides of the septum existed throughout the mapping period with no 2 consecutive WF activation patterns matching. Single linear WFs were the most prevalent activation pattern on both septal grids. No focal breakthroughs were seen. Transient rotational activity was seen in 10% of phase activations. During SR and atrial pacing, both grids appeared to be activated independent of each other with no evidence of contralateral conduction across the 2 grids. Simultaneous biatrial septal mapping of human PeAF, SR, and atrial pacing shows complete WF dissociation between the left and right IAS with no evidence of trans-septal conduction, indicating that the 2 sides function as electrically discrete structures. No stable septal drivers were observed. These findings may have implications for mapping and ablation of PeAF.

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.

Outcomes of radiofrequency catheter ablation for persistent and long-standing persistent atrial fibrillation

ObjectiveTo assess one-year outcomes in patients with persistent and long-standing persistent atrial fibrillation (AF) treated by catheter ablation. MethodsA retrospective observational study was conducted of consecutive patients referred for catheter ablation of persistent or long-standing persistent AF between May 2016 and October 2018. Patients underwent two different ablation strategies: pulmonary vein isolation (PVI) plus complex fractionated atrial electrograms (CFAE) (from May 2016 to June 2017) or a tailored approach (from July 2017 to October 2018). The overall recurrence rate at one year was analyzed. The secondary endpoint was arrhythmia recurrence according to the type of AF (persistent vs. long-standing persistent AF) and according to the ablation strategy employed. ResultsDuring the study period, 67 patients were included (40% with long-standing persistent AF). During a mean follow-up of 16±6 months, 27% of the patients had arrhythmia recurrence. Patients with long-standing persistent AF had a higher recurrence rate than those with persistent AF (44.4% vs. 15%, p=0.006), while patients who underwent a tailored approach presented better outcomes than those undergoing PVI plus CFAE ablation (17.5% vs. 40.7%, p=0.024). Ablation strategy (HR 6.457 [1.399-29.811], p=0.017), time in continuous AF (HR 1.191 [1.043-1.259], p=0.010) and left atrial volume index (HR 1.160 [1.054-1.276], p=0.002) were independent predictors of arrhythmia recurrence. ConclusionCatheter ablation is an effective treatment for patients with persistent and long-standing persistent AF. Patients with persistent AF and those undergoing a tailored approach presented lower arrhythmia recurrence.

Relationship between temporal rhythm-based classification of atrial fibrillation and stroke: real-world vs. clinical trial

BackgroundThe risk of stroke according to clinical classification of atrial fibrillation (AF) remains poorly defined. Here, we assessed the impact of AF type on stroke risk in vitamin K antagonist-treated patients with AF in ‘real-world’ and ‘clinical trial’ cohorts.MethodsPost-hoc analysis of patient-level data from the Murcia AF Project and AMADEUS trial. Clinical classification of AF was based on contemporary recommendations from international guidelines. Study endpoint was the incidence rate of ischaemic stroke. Stroke risk was determined using CHA2DS2-VASc score and CARS. A modified CHA2DS2-VAS‘c’ score that applied one additional point for a ‘c’ criterion of continuous AF (i.e. non-paroxysmal AF) was calculated.ResultsWe included 5,917 patients: 1,361 (23.0%) real-world and 4,556 (77.0%) clinical trial. Baseline demographics were balanced in the real-world cohort but clinical trial participants with non-pAF (vs. pAF) were older, male-predominant and had more comorbidities. Crude stroke rates were comparable between the groups in real-world patients (IRR 0.72 [95% CI,0.37-1.28], p = 0.259) though clinical trial participants with non-pAF had a significantly higher crude rate of stroke events (IRR 4.66 [95%,CI,2.41-9.48], p < 0.001). Using multivariable analysis, AF type was not independently associated with stroke risk in the real-world (adjusted HR 1.41 [95% CI,0.80-2.50], p = 0.239) and clinical trial (adjusted HR 1.16 [95% CI,0.62-2.20], p = 0.646) cohorts, after accounting for other risk factors. There was no significant improvement in the CHA2DS2-VAS‘c’ compared to CHA2DS2-VASc score in either cohorts (p > 0.05).ConclusionsOverall, our results support the need for anticoagulation based on thromboembolic risk profile rather than AF type.

Increased plasma levels of NT-proBNP, Troponin T and GDF-15 are driven by persistent AF and associated comorbidities: Data from the AF-RISK study.

Atrial fibrillation (AF) is a progressive disease, and early recognition and management may reflect an important strategy to reduce its disease burden. In this study, we evaluated plasma levels of three biomarkers - N-terminal pro-brain natriuretic peptide (NTproBNP), Troponin-T, and growth differentiation factor-15 (GDF-15) - in patients with paroxysmal AF (pAF) (≤7 days of continuous AF, n = 323) and persistent AF ((AF duration > 7 days and < 1 year, n = 84) using patients from AF RISK study (NCT01510210). In this AF-RISK sub-study, patients with persistent AF experienced more symptoms (higher European Heart Rhythm Association class (p < 0.001)), had a higher comorbidity burden (p < 0.001), and had more unfavorable echocardiographic parameters (p < 0.001). All three biomarker levels were significantly higher in patients with persistent AF as compared to those with pAF (p < 0.001). Multivariate linear regression analyses showed that age (beta-coefficient for NTproBNP: 0.21; GDF-15: 0.41; Troponin-T: 0.23) and CHA2DS2-VASc (beta-coefficient for NTproBNP: 0.20; GDF-15: 0.25; Troponin-T: 0.27) were determinants of all three biomarkers, and that persistent AF determined NTproBNP (beta-coefficient: 0.34), but not Troponin-T and GDF-15. More detailed analysis of CHA2DS2-VASc score showed that for all three biomarkers age, coronary artery disease and heart failure were determinants of plasma biomarkers levels, whereas sex determined NTproBNP and Troponin T, and hypertension determined NTproBNP and GDF15. Overall, this study therefore suggests that in AF, Troponin T and GDF15, and especially NTproBNP could be used to detect those patients with more persistent form of AF that may warrant more aggressive treatment of AF and concomitant comorbidities. Future studies, however, are essential to evaluate if more aggressive AF treatment and risk factor management will reduce disease progression and holds a novel therapeutic intervention to reduce the burden of AF.

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.