Atrial Fibrillation Rhythm Research Articles

A study of complex network features for electrocardiograms and its Applications in atrial fibrillation recognition

Atrial fibrillation (AF) is one of the most common arrhythmias in clinics. The traditional diagnosis of AF mainly depends on physicians’ visual observation of electrocardiograms (ECGs), which is an inefficient, time-consuming, and laborious task. Rapidly evolving complex network principles have opened up a new avenue for studying AF rhythm recognition. This paper thoroughly analyzes seventeen existing network features and proposes three novel network features: local efficiency distribution entropy (EDE), clustering coefficient distribution entropy (CDE), and degree distribution entropy (DDE). Different from the existing local efficiency entropy and clustering coefficient entropy, the three distribution entropy features can reflect probability distributions of network features. This paper compares EDE, CDE, and DDE with existing network features by using T-test, box plots, and machine learning models to validate their effectiveness in AF rhythm recognition. The experiments on PhysioNet/CinC Challenge 2017 show that EDE, CDE, and DDE are superior to existing network features and the accuracy of AF recognition can achieve 94.96%, 94.72% and 95.58%, respectively, when using time-domain features plus EDE, CDE, and DDE.

Abstract 4118387: Artificial Intelligence-Enhanced Echocardiogram Assessment Helps Distinguish Cardiomyopathy from Beat-to-Beat Variation in Atrial Fibrillation

Background: Atrial fibrillation (AF) can be associated with reductions in left ventricular ejection fraction (LVEF) that improve upon conversion of AF to sinus rhythm. Such LVEF changes during AF may be due to LVEF measurement error from beat-to-beat variations related to AF itself. More precise artificial intelligence (AI)-enhanced LVEF assessment could help distinguish between such LVEF “pseudo-reduction” during AF and true cardiomyopathy, thus potentially preventing unnecessary downstream workup and treatment. Methods: Using a transthoracic echocardiogram database at a large academic medical center, we identified all patients whose LVEF fell below 50% while in AF who had subsequent LVEF recovery to over 50% within 90 days after converting from AF to sinus rhythm. For echocardiograms in AF, we compared the clinically assessed LVEF with AI-enhanced LVEF assessment by EchoNet-Dynamic, a validated deep learning algorithm. Results: In our cohort of 84 patients, the mean age was 74 years old, 36.9% were female, and 26.2% non-White. The mean LVEF recovery was 19.3% (95% CI 17.1-21.5%) after converting from AF to sinus rhythm with a mean duration of 27.4 days between the AF and sinus rhythm echocardiograms (Figure 1). For AF echocardiograms, the LVEF when reassessed by deep learning was 8.4% (6.3-10.5%) higher than the original clinical read, resulting in 30.3% of patients being reclassified as no longer having a reduced LVEF less than 50% while in AF. Among these patients with LVEF reductions during AF, 27.4% and 19.0% were given a new or worsened heart failure with reduced ejection fraction (HFrEF) diagnosis, 15.5% underwent ischemic testing, and 17.9% were started on new HFrEF medications. Discussion: LVEF reductions during AF can lead to new HFrEF diagnosis, workup, and treatment. However, such LVEF reductions may be temporary and partially explained by undermeasurement of LVEF during AF. AI-enhanced LVEF assessment may help reduce such measurement errors during AF and thereby prevent overdiagnosis of HFrEF. Further research is needed to understand the clinical significance of true but temporary LVEF reductions during AF.

Circadian rhythm in atrial fibrillation detected by implantable loop recorder: a post-hoc analysis of a randomized clinical trial

Abstract Introduction Previous studies suggest the existence of circadian, weekly, and seasonal rhythms in the occurrence of atrial fibrillation (AF), which may be utilized to improve the yield of screening. The heterogeneity of AF natural history also necessitates better phenotyping to overcome the challenges of identifying candidates for screening and treatment. Purpose To explore the potential circadian rhythm in AF occurrence in persons without known arrhythmia but at high risk of AF and stroke. Methods Post-hoc analysis of the LOOP study (Atrial Fibrillation Detected by Continuous Electrocardiogram Monitoring Using Implantable Loop Recorder to Prevent Stroke in High-Risk Individuals), which randomized 6004 AF naïve participants (≥70 years old with additional stroke risk factors) 1:3 to receive implantable loop recorder screening or usual care. All loop recorder data was extracted to obtain the date and time of AF episode onset, AF duration, mean and max heart rate (HR) during AF, and symptom annotations. New-onset AF episodes lasting ≥6 minutes were adjudicated, and all subsequent episodes were included in the analysis. Results A total of 41,713 AF episodes (median duration 18 (8-64) minutes) were identified among 430 participants (Table 1). The median number of episodes for each participant with AF was 21 (4-82) and the median AF burden was 0.17% (0.04%-0.83%) of time from debut to end of monitoring. The most and least frequent days of AF onset were Sunday (15.3%) and Friday (13.6%), respectively, while AF occurred slightly more often during spring (26%) than in other seasons. The median time of onset was 09:57:15 AM (05:15:30 AM – 03:33:00 PM). The most frequent time of onset was at 09:00 AM (rounded to the nearest hour), which was two times more likely than at 09:00 PM, and 22% of all episodes occurred between 08:00 and 11:00 AM (Figure 1). A total of 25,329 (61%) episodes occurred between midnight and noon (AM). Nocturnal episodes, defined as episodes with onset between 10:00 PM and 07:00 AM, occurred in 368 (86%) AF participants and constituted a median of 40% of all episodes and 37% (14%-63%) of each participant’s episodes. The median duration of nocturnal episodes was 28 (10-104) minutes compared to 14 (8-44) minutes for daytime episodes. The averaged heart rate during AF was 81 (71-96) beats per minute (BPM), while 330 (77%) participants had AF episodes with heart rates equal to or above 100 BPM, and the duration of these episodes was 50 (15-201) minutes compared to 30 (21-85) minutes for slower episodes (below 100 BPM). Conclusion A circadian pattern was observed for screening-detected AF. AF onset occurred predominantly between 08:00 and 11:00 AM, representing more than one in five episodes. Nocturnal AF occurred in most participants with AF and accounted for almost half of all episodes, while these episodes also lasted longer than daytime episodes. This may warrant future studies investigating the timing of AF screening.

Procedural outcomes of fluoroscopy-less catheter ablation for atrial fibrillation

Abstract Background Radiofrequency catheter ablation is superior therapy to antiarrhythmic drugs for maintaining sinus rhythm in atrial fibrillation (AF) patients. Traditional fluoroscopy-guided AF ablation poses risks of prolonged radiation exposure for both patients and medical staff. Recent advancements in fluoroscopy-less catheter ablation techniques offer potential solutions, but comprehensive data on their effectiveness and safety are lacking. Purpose To evaluate the procedural outcomes and safety of fluoroscopy-less catheter ablation for AF compared to fluoroscopy-guided ablation. Methods Retrospective observational study of consecutive AF ablations (N=881) conducted at a university teaching hospital (Hamilton Health Sciences, Hamilton, Ontario) from November 2017 to September 2022. An electro-anatomical mapping system and ICE was used in all cases. Baseline characteristics and procedural outcomes between the fluoroscopy-less and fluoroscopy-guided groups were compared. Cases that used <60 seconds of fluoroscopy (occasionally used by operators during the placement of an esophageal probe) were included in the fluoroscopy-less group (N= 68). Results Mean age of individuals was 60.6 ± 11 years, 71.7% were male, 72.6% had paroxysmal AF, mean CHA2DS2-VASc score was 1.6 ± 1.4, 11.1% had prior heart failure, and mean left ventricular ejection fraction was 57.5 ± 15%. There were no significant differences in patient baseline characteristics between the fluoroscopy-less and fluoroscopy groups. Total procedure and fluoroscopy times were lower in the fluoroscopy-less group compared to the fluoroscopy-guided group (169.3 ±42 minutes vs. 192.1 ±54 minutes, p<0.0001 and 0.024 ±0.10 vs. 10.0 ±7.4 minutes , p<0.0001). Fluoroscopy-less AF ablation remained an independent predictor of lower procedure times following adjusting for the use of general anesthesia, high-power short-duration, presence of trainees, AF pattern, redo cases, and type of mapping system. Complication rates were similar between fluoroscopy-less and fluoroscopy-guided ablation (1.9% vs. 3.8%, p=0.11). Conclusion Fluoroscopy-less catheter ablation for AF appears to have similar procedural outcomes and safety than fluoroscopy-guided AF ablation.

Dysfunctional atrial fibroblast processing of filamin A in atrial fibrillation

Abstract Background/Introduction Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is associated with atrial structural remodelling, hallmarked by fibrosis. Atrial fibrosis is instigated by atrial fibroblasts (AFBs). It was previously uncovered the hormone calcitonin (CT) is produced in the heart and, via binding to the CT-receptors (CTR), inhibits atrial fibrogenesis and fibroblast profibrotic activity. [1] In AF, abnormally increased CTR internalisation causes loss of physiological surface CTR and prevents fibroblast activation by CT. The molecular mechanisms of this phenomenon in ACFs are unknown. Aim To explore the role of filamin A (FLNa), an actin cross-linking protein that was previously shown to interact with CTR, [2] in the regulation of CTR trafficking. Methods AFBs were enzymatically isolated from left atrial appendage biopsies collected from 30 patients in persistent AF or normal sinus rhythm (SR, controls) undergoing elective heart surgery. Immunostaining assessed the localisation of CTR and its overlap with the nucleus (stained with DAPI) and FLNa in AFBs. Co-localisation was quantified by the JACoP BIOP plugin for ImageJ. Target mRNA expression was assessed by RT-qPCR and protein levels by immunoblot. Immunoprecipitation (IP) then immunoblot (IB) validated protein-protein interactions. Calpain activity was assessed with a fluorescence-based assay. The effects of calpains on FLNa proteolytic processing was examined with calpain inhibitor calpeptin (10nM–100nM vs DMSO loading control). Results Immunostaining revealed aberrant, intracellular localisation of CTR in AF-AFBs (A) with increased nuclear localisation (p=0.03) and reduced co-localisation with FLNa (p=0.03). FLNa gene expression showed a trend towards reduction in AF (by 36%, p=0.06; B). Meanwhile, although full-length FLNa protein was unaltered in AF, there was a striking 67% reduction (p=0.02) in the expression of FLNa’s c-terminal fragment (FLNaCT), which contains the CTR binding domain (C). Co-immunoprecipitation confirmed a physical interaction between CTR and FLNaCT (D) in both SR and AF AFBs. FLNaCT is typically generated when FLNa is cleaved by the protease calpain 1, whose protein (F) but not mRNA (E), was significantly downregulated (71%, p<0.001) in AF. Puzzlingly, a ~70% loss of calpain 1 protein was associated with unchanged calpain activity (G) and FLNaCT levels in AFBs treated with calpain inhibitor calpeptin (H). Conclusions Persistent AF is associated with an aberrant CTR localisation and FLNa proteolytic processing, not attributable to altered calpain activity. Further characterisation of the molecular determinants of the altered CTR localisation may uncover novel and potentially druggable facets of structural remodelling in AF.

Comparison of left atrial and left atrial appendage mechanics in patients with ischaemic strokes of different aetiologies

Abstract Background Left atrial (LA) and left atrial appendage (LAA) mechanical dysfunction account for an increase in cardioembolic stroke risk in atrial fibrillation (AF), and more recently in individuals in sinus rhythm (SR). However, the exact contribution of LA and LAA to the pathogenesis of thromboembolic events is not fully understood. Here, we aimed to assess the alterations of LA and LAA mechanics in different stroke subtypes. Methods We recruited three groups of participants: patients with paroxysmal or persistent AF with a history of stroke (AF-stroke, n=69,respectively), individuals in SR with no history of AF but with acute ischaemic stroke(non-AF stroke,n=46); individuals with no history of AF or stroke(control group,n=17). Patients with AF were further categorized into sinus rhythm group (AF-stroke-SR,n=24) and AF rhythm group(AF-stroke-AF, n=45) according to the rhythm at the time of echocardiography. Using speckle-tracking echocardiography, global longitudinal strain (GLS) and mechanical dispersion (MD) of LA and LAA were measured in all patients. Mechanical dispersion was defined as the standard deviation of the time to peak of the regional strain corrected by R-R interval. Results Patients with AF-stroke demonstrated prominently impaired LA and LAA mechanics(LA GLS: 20±6%(AF-stroke-SR),11±4%(AF-stroke-AF); LA MD: 9±3%,11±3%; LAA GLS: 15±3%,11±4% ; LAA MD: 11±4%,12±3% ,respectively) compare with those with non-AF stroke and controls (LA GLS:35±8%, 41±11%;LA MD,6±2%, 4±2%; LAA GLS:21±5%, 23±7%; LAA MD:8±4%, 7±3%,respectively) (all p<0.01). Interestingly, LA and LAA mechanical function was not significantly different between patients with non-AF strokes and the control group. In multivariable analysis, only AF-strokes were independently associated with LA and LAA GLS after adjusting for age and comorbidities (both P<0.01). Conclusions Mechanical dysfunction of LA and LAA might play a greater role in pathogenesis of strokes related to AF rather than non-AF strokes.

Sinusoidal Atrial Fibrillation (Yasser’s Fibrillation) and Partial SAN Function in COVID-19 Pneumonia; a New Cardiovascular Discovery Change in Atrial Fibrillation Directory

Introduction: Atrial fibrillation (AF) is one of the most common and probable serious arrhythmias and a hallmark of an increasing risk of pathological thrombus formation. Interestingly, normal sinus rhythm (NSR) is the standard rhythm in a normal person. The sino-atrial node (SAN) is the heart's pacemaker and generator of the normal electrical conduction system of the heart which allows for the generating of electrical impulses. In AF, the normal regular electrical impulses generated by the sinoatrial node are overwhelmed by disorganized electrical waves, usually originating from the roots of the pulmonary veins. These disorganized waves conduct intermittently through the atrioventricular node (AVN) leading to irregular activation of the ventricles that generate the heartbeat. Cases presentation: Four different cases were described. 1. An elderly female patient presented to the ICU with metastatic complicated Mantle cell lymphoma, COVID-19 pneumonia, and irregular heart rate. 2. A senile male patient presented to the intensive care unit (ICU) with an aortic aneurysm, COVID-19 pneumonia, consumptive thrombocytopenia, lung fibrosis, and irregular heart rate. 3. A middle-aged female presented to the ICU with chronic renal failure (CRF) on regular hemodialysis, liver cell failure (LCF), pseudo-orange abdominal cellulitis, valvular heart replacement, and irregular heart rate. 4. An elderly female patient presented with cardiomyopathy, global cardiomegaly, irregular heart rate, diabetes, pseudo-orange abdominal cellulitis, liver cirrhosis, and COVID-19 pneumonia. Method of study and patients: Retrospective-Observational four case report series study was conducted in Kafr El-Bateekh Central Hospital staring from January 21, 2023 and ending on June 24, 2024 on COVID-19 pneumonia and atrial fibrillations. Conclusion: Sinusoidal atrial fibrillations (Yasser’s fibrillation) or mixed AF are a new cardiovascular discovery. The partial sino-atrial nodal function has essential role in the presence of Sinusoidal atrial fibrillations (Yasser’s fibrillation) or mixed AF and its interpretation. Sinusoidal atrial fibrillations (Yasser’s fibrillation) or mixed AF may be balanced between AF and normal sinus rhythm. The percentages of normal sinus beats to AF beats in the cases of Sinusoidal atrial fibrillations (Yasser’s fibrillation) may be a guide for approximate healthy or sick part of the sinoatrial node. Widening the research for the Sinusoidal atrial fibrillations (Yasser’s fibrillation) or mixed AF will be recommended.

Novel Method for Risk Stratification of Major Adverse Clinical Events Using Pre- and Post-Ablation Left Atrial Volume Index in Patients With Persistent Atrial Fibrillation.

The relationship between changes in the left atrial volume index (LAVI) post-catheter ablation (CA) and long-term prognostic events in patients with persistent atrial fibrillation (AF) remains unclear. We evaluated the incidence of major adverse clinical events (MACE), including all-cause death, unplanned heart failure hospitalization, and unplanned cardiovascular hospitalization using pre- and post-CA LAVI. We collected data retrospectively from 150 patients with persistent AF who underwent their first CA. LAVI was calculated during preprocedural echocardiography under AF rhythm (pre-CA LAVI) and 3 months post-CA under sinus rhythm (post-CA LAVI). The cumulative incidence of MACE was compared among 3 subgroups based on the cutoff values of pre-CA (45.5 mL/m2) and post-CA (46.5 mL/m2; both determined using the c-statistic) LAVI. The subgroup of a pre-CA LAVI >45.5 mL/m2 with a post-CA LAVI >46.5 mL/m2 (n=45) had a significantly higher MACE incidence compared with other subgroups (P=0.002). Multivariate analysis identified this subgroup as independently at higher risk for MACE. The subgroup of a pre-CA LAVI >45.5 mL/m2 with a post-CA LAVI ≤46.5 mL/m2 (n=49) had an incidence comparable with those with pre-CA LAVI ≤45.5 mL/m2 (n=56) and exhibited a significantly greater reduction in LAVI than other subgroups did (P<0.001). Combining pre-CA and post-CA LAVIs is valuable in stratifying long-term MACE development risk following CA.

A deep learning method for beat-level risk analysis and interpretation of atrial fibrillation patients during sinus rhythm

Atrial Fibrillation (AF) is a common cardiac arrhythmia. Many AF patients experience complications such as stroke and other cardiovascular issues. Early detection of AF is crucial. The great majority of algorithms can only distinguish “AF rhythm in AF patients” from “sinus rhythm in healthy individuals” . However, AF patients do not always exhibit AF rhythm, most of the time they present with sinus rhythms, and there is also a potential risk of AF in sinus rhythms. How to detect AF from sinus rhythm is a challenge. To address this, this paper proposes a novel artificial intelligence (AI) algorithm to distinguish “sinus rhythm in AF patients” and “sinus rhythm in healthy individuals” in beat-level. We cut 1 s of sinus beats from single-lead Electrocardiogram (ECG) data and fed them to the Net1d model, a deep learning model that processes one-dimensional data, to obtain the risk probability of each beat. Besides, we have also introduced the beat-level risk interpreters, trend risk interpreters, addressing the interpretability issues of deep learning models and the difficulty in explaining AF risk trends. Additionally, the beat-level information fusion decision is presented to enhance model accuracy. The experimental results demonstrate that the average AUC for single beats used as testing data from CPSC 2021 dataset is 0.7314, with an average accuracy of 0.6606 and an F1 score of 0.6470. By employing 150 beats for information fusion decision algorithm, the average AUC can reach 0.7591, while the average accuracy and F1 score improve to 0.6887 and 0.6749. Compared to previous segment-level algorithms, we utilized beats as input, reducing data dimensionality and making the model more lightweight, facilitating deployment on portable medical devices. Furthermore, we draw new and interesting findings through average beat analysis and subgroup analysis, considering varying risk levels. Our code is publicly available at https://github.com/leijsen/ECGBeat4AFSinus.

Smartphone app-based approximation of time spent with atrial fibrillation and symptoms in patients after catheter ablation: Data from the TeleCheck-AF project.

Reduction of atrial fibrillation (AF) burden is the preferred outcome measure over categorical AF rhythm recurrence after AF ablation. In this sub-analysis of the TeleCheck-AF project we tested the feasibility of smartphone app-based approximation of time spent with AF and/or symptoms. Patients scheduled for at least one teleconsultation during the 12-month follow-up after AF ablation were instructed to use a smartphone photoplethysmography (PPG)-based application for simultaneous symptom and rhythm monitoring 3-times daily for 1 week. Proxies of time spent with AF and/or symptoms (%-recordings, load, %-days), temporal aggregation of AF and/or symptoms (density), and symptom-rhythm correlation (SRC) were assessed. In total 484 patients (60% male, 62±9.9 years) were included. Adherence, motivation and patient satisfaction were high. %AF-recordings, AF load and %AF-days (rs= 0.88-0.95) and %symptom-recordings, symptom load, %symptom-days (rs= 0.95-0.98) showed positive correlations. The SRC correlated negatively with time spent with symptoms (rs=-0.65--0.90) and with time spent with AF (rs=-0.31--0.34). In patients with paroxysmal AF before ablation and AF during the monitoring period, 87% (n=39/44) had a low-density score <50% ("paroxysmal AF pattern") while 5% (n=2/44) had a high-density score >90% ("persistent AF pattern"). Corresponding numbers for patients with persistent AF before ablation were 48% (n=11/23) and 43% (n=10/23), respectively. On-demand, app-based simultaneous rhythm and symptom assessment provides objective proxies of time spent with AF and/or symptoms and symptom-rhythm correlation, which may assist in assessing AF and symptom outcomes after AF ablation.

The effect of fixed and functional remodelling on conduction velocity, wavefront propagation, and rotational activity formation in atrial fibrillation.

Pathophysiology of atrial fibrillation (AF) remains unclear. Interactions between scar and conduction velocity (CV) and their impact on wavefront propagation in sinus rhythm (SR) and rotational activity burden in AF were evaluated. Local activation times (LATs) and voltage data were obtained from patients undergoing ablation for persistent AF. Omnipolar voltage (OV) and bipolar voltage (BV) data were obtained during AF and SR at pacing intervals of 600 and 250 ms. Local activation times were used to determine CV dynamics and their relationship to the underlying voltage and pivot points in SR. Computational modelling studies were performed to evaluate the impact of CVs and fibrosis on rotational activity burden in AF. Data from 60 patients with a total of 2 768 400 LAT and voltage points were analysed (46 140 ± 5689 points/patient). Voltage determined CV dynamics. Enhanced CV heterogeneity sites were predominantly mapped to low-voltage zones (LVZs) (0.2-0.49 mV) (128/168, 76.2%) rather than LVZs (<0.2 mV) and frequently co-located to pivot points (151/168, 89.9%). Atrial fibrillation OV maps correlated better with SR BV 250 ms than 600 ms maps, thereby representing fixed and functional remodelling. Sinus rhythm maps at 250 ms compared with 600 ms harboured a greater number of pivot points. Increased CV slowing and functional remodelling on computational models resulted in a greater rotational activity burden. Conduction velocity dynamics are impacted by the degree of scar. Conduction velocity heterogeneity and functional remodelling impacts wavefront propagation in SR and rotational activity burden in AF. This study provides insight into the pathophysiology of AF and identifies potential novel ablation targets.

Atrial Imaging and Cardiac Rhythm in Cryptogenic Embolic Stroke: The ARIES Study.

Unknown cardioembolic sources are frequent causes of cryptogenic stroke. We analyzed the risk of atrial fibrillation (AF) or high burden of ectopic atrial activity (HBEA) in patients with cryptogenic stroke, assessing atrial function and 1-year outcomes. The ARIES (Atrial Imaging and Cardiac Rhythm in Cryptogenic Embolic Stroke) study is an observational study including patients with cryptogenic stroke. We analyzed the frequency of AF and HBEA (>3000 atrial ectopic beats/day or >2 bursts or atrial tachycardia between 3 beats and ≤30 seconds) in two 30-day Holter-ECGs, comparing advanced echocardiography signs of left atrial (LA) dysfunction according to rhythm: AF, HBEA, and normal sinus rhythm. We also evaluated 1-year stroke recurrence and mortality. The study included 109 patients; 35 (32.1%) patients had AF, 27 (24.8%) HBEA, and 47 (43.1%) normal sinus rhythm. Compared with those with normal sinus rhythm, patients with AF presented higher 2-dimensional and 3-dimensional LA indexed volumes (38.8±11.2 versus 27.3±11.8 mL/m2, and 50.6±17.2 versus 34.0±15.4 mL/m2, respectively, P<0.001), lower 3-dimensional LA ejection fraction (50±14.6 versus 62.7±11.8, P=0.001), LA reservoir strain (22.0±8.6 versus 30.4±10.5, P<0.001), and LA contraction strain (10.5±8.18 versus 17.1±7.5, P<0.001), remaining significant in multivariate analysis. Patients with HBEA showed higher LA indexed volumes and lower LA reservoir strain than patients with normal sinus rhythm only in univariate analysis. There were no differences in ischemic recurrence or mortality among the groups. Patients with cryptogenic stroke showed a high incidence of AF and HBEA. AF is strongly related to LA volume, LA function, and LA reservoir and contraction strain, whereas HBEA showed milder structural changes. Advanced LA echocardiography could help patient selection for long-term ECG monitoring in suspected cardiac sources.

Biomarker-based prediction of sinus rhythm in atrial fibrillation patients: the EAST-AFNET 4 biomolecule study.

In patients with atrial fibrillation (AF), recurrent AF and sinus rhythm during follow-up are determined by interactions between cardiovascular disease processes and rhythm-control therapy. Predictors of attaining sinus rhythm at follow-up are not well known. To quantify the interaction between cardiovascular disease processes and rhythm outcomes, 14 biomarkers reflecting AF-related cardiovascular disease processes in 1586 patients in the EAST-AFNET 4 biomolecule study (71 years old, 46% women) were quantified at baseline. Mixed logistic regression models including clinical features were constructed for each biomarker. Biomarkers were interrogated for interaction with early rhythm control. Outcome was sinus rhythm at 12 months. Results were validated at 24 months and in external datasets. Higher baseline concentrations of three biomarkers were independently associated with a lower chance of sinus rhythm at 12 months: angiopoietin 2 (ANGPT2) (odds ratio [OR] 0.76 [95% confidence interval 0.65-0.89], p=0.001), bone morphogenetic protein 10 (BMP10) (OR 0.83 [0.71-0.97], p=0.017) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) (OR 0.73 [0.60-0.88], p=0.001). Analysis of rhythm at 24 months confirmed the results. Early rhythm control interacted with the predictive potential of NT-proBNP (pinteraction=0.033). The predictive effect of NT-proBNP was reduced in patients randomized to early rhythm control (usual care: OR 0.64 [0.51-0.80], p<0.001; early rhythm control: OR 0.90 [0.69-1.18], p=0.453). External validation confirmed that low concentrations of ANGPT2, BMP10 and NT-proBNP predict sinus rhythm during follow-up. Low concentrations of ANGPT2, BMP10 and NT-proBNP identify patients with AF who are likely to attain sinus rhythm during follow-up. The predictive ability of NT-proBNP is attenuated in patients receiving rhythm control.

NR4A3 prevents diabetes induced atrial cardiomyopathy by maintaining mitochondrial energy metabolism and reducing oxidative stress

Atrial cardiomyopathy (ACM) is responsible for atrial fibrillation (AF) and thromboembolic events. Diabetes mellitus (DM) is an important risk factor for ACM. However, the potential mechanism between ACM and DM remains elusive. Atrial tissue samples were obtained from patients diagnosed with AF or sinus rhythm (SR) to assess alterations in NR4A3 expression, and then two distinct animal models were generated by subjecting Nr4a3-/- mice and WT mice to a high-fat diet (HFD) and Streptozotocin (STZ), while db/db mice were administered AAV9-Nr4a3 or AAV9-ctrl. Subsequently, invivo and invitro experiments were conducted to assess the impact of NR4A3 on diabetes-induced atrial remodeling through electrophysiological, biological, and histological analyses. RNA sequencing (RNA-seq) and metabolomics analysis were employed to unravel the downstream mechanisms. The expression of NR4A3 was significantly decreased in atrial tissues of both AF patients and diabetic mice compared to their respective control groups. NR4A3 deficiency exacerbated atrial hypertrophy and atrial fibrosis, and increased susceptibility to pacing-induced AF. Conversely, overexpression of NR4A3 alleviated atrial structural remodeling and reduced AF induction rate. Mechanistically, we confirmed that NR4A3 improves mitochondrial energy metabolism and reduces oxidative stress injury by preserving the transcriptional expression of Sdha, thereby exerting a protective influence on atrial remodeling induced by diabetes. Our data confirm that NR4A3 plays a protective role in atrial remodeling caused by diabetes, so it may be a new target for treating ACM. This study was supported by the major research program of National Natural Science Foundation of China (NSFC) No: 82370316 (to Q-S. W.), No. 81974041 (to Y-P. W.), and No. 82270447 (to Y-P. W.) and Fundation of Shanghai Hospital Development Center (No. SHDC2022CRD044 to Q-S. W.).

Clinical characteristics of atrial fibrillation in nonagenarian population and relationship with mortality.

There is a considerable amount of literature available on well-known risk factors for atrial fibrillation (AF); however, available data specifically focused on the ninth decade are scarce. The main objective of this study was to assess the demographic and clinical characteristics of AF and sinus rhythm in a nonagenarian population. All individuals aged >90 years who were admitted to the Cardiology outpatient clinic between April 2018 and January 2019 were enrolled in the study. The demographic and clinical characteristics of all patients were recorded. All deaths that occurred during the two-year follow-up period were recorded. In total, 112 nonagenarian individuals were included in the study. Of these patients, 50 (44.6%) had AF. The groups showed similarities in demographic and clinical characteristics. During a mean follow-up period of 596±44 days, 39 patients (78%) in the AF group and 35 patients (56.5%) in the sinus group died. Patients with AF showed a lower overall survival distribution than those with sinus rhythm (P=0.005, log-rank test χ2=7.734). AF was associated with an increased risk of mortality (P=0.002, hazard ratio [HR] =2.104, 95% confidence interval [CI] = 1.326-3.339) in multivariate Cox regression analysis, while waist circumference and total cholesterol (P=0.003, HR=0.969, 95% CI=0.949-0.989 and P=0.046, HR=0.993, 95% CI=0.986-1.000, respectively) showed a decreased risk of mortality. Atrial fibrillation is very common in individuals over the age of 90 years (44.6%). Well-known risk factors do not appear to be effective in this age group, and AF is associated with a 2.1-fold increase in the risk of mortality.

ST-segment depression and left ventricular systolic function recovery post-atrial fibrillation ablation in heart failure.

Catheter ablation (CA) of atrial fibrillation (AF) improves left ventricular ejection fraction (LVEF) in patients with heart failure with reduced ejection fraction (HFrEF). The impact of ST-segment depression before CA on LVEF recovery and clinical outcomes remains unknown. In the present study, we aimed to investigate the relationship between ST-segment depression during AF rhythm before CA and improvement in the LVEF and clinical outcomes in persistent atrial fibrillation (PerAF) patients with HFrEF. The present study included 122 PerAF patients (male; 98 patients, 80%, mean age: 69 [56, 76] years) from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry who had LVEF<50% and underwent an initial ablation. The patients who underwent percutaneous coronary intervention or coronary artery bypass grafting within the past 1month were not included in the enrolled patients. We assigned the patients based on the presence of ST-segment depression before CA during AF rhythm and evaluated improvement in the LVEF (LVEF≥15%) 1year after CA and the relationship between ST-segment depression and heart failure (HF) hospitalization/major adverse cardiovascular events (MACE), which are defined as a composite of HF hospitalization, cardiovascular death, hospitalization due to coronary artery disease, ventricular arrhythmia requiring hospitalization and stroke. The percentage of patients with improvement in the LVEF 1year after CA was significantly lower in the patients with ST-segment depression than those without (58.6% vs. 79.7%, P=0.012). Multiple regression analysis showed ST-segment depression was independently and significantly associated with improvement in the LVEF 1year after CA (HR: 0.35; 95% CI: 0.129-0.928, P=0.035). Kaplan-Meier analysis showed that the patients with ST-segment depression significantly had higher risk of HF hospitalization and MACE than those without (log rank P=0.022 and log rank P=0.002, respectively). Multivariable Cox proportional hazards analysis showed that ST-segment depression was independently and significantly associated with a higher risk of MACE (HR: 2.82; 95% CI: 1.210-6.584, P=0.016). ST-segment depression before CA during AF rhythm was useful prognostic predictor of improvement in the LVEF and clinical outcomes including HF hospitalization and MACE in PerAF patients with HFrEF.

Characteristics and Clinical Outcomes of Patients Hospitalized for Acute Heart Failure Who Develop Atrial Fibrillation or Convert to Sinus Rhythm

Atrial fibrillation (AF) is the most common sustained arrhythmia in acute heart failure (AHF), with a prevalence of approximately 35%. However, little is known about the clinical characteristics and outcomes of in-hospital conversion from AF to sinus rhythm and vice versa. In a post hoc secondary analysis of the randomized, double-blind, placebo-controlled PROTECT trial in patients with AHF, we identified 4 groups of patients: AF at admission and in-hospital conversion to sinus rhythm (n = 44); in-hospital development of AF (n = 31); persistent AF (n = 278); and continuous sinus rhythm (n = 410). Conversion from AF to sinus rhythm (13.7%) and from sinus rhythm to AF (7.0%) occurred only in a minority of patients. Patients with AF who converted to sinus rhythm were more often classified as being in New York Heart Association class IV, had higher heart rates and higher respiratory rates at hospital admission, whereas patients who developed AF were older, more likely to be female and had the highest ejection fractions compared to continuous sinus rhythm (all P < 0.05). Conversion to sinus rhythm or development of AF occurred mainly within the first 24 hours after hospital admission. Patients with persistent AF and those who developed AF had longer median lengths of hospital stay (8 vs 7 days; P < 0.001 and 9 vs 7 days; P < 0.001, respectively), compared to those with continuous sinus rhythm. In both univariable and multivariable analyses, there was no significant association between the AF groups and the primary clinical outcomes of either 180-day all-cause mortality or 60-day death or readmission for heart failure. In patients hospitalized for AHF, only few converted from AF to sinus rhythm or sinus rhythm to AF. Although development of AF or persistent AF was associated with longer lengths of hospitalization, midterm mortality and readmission rates were similar in the groups.

The heart rate response to the 6-min walk test in atrial fibrillation patients with or without beta-blockers: Referring to patients with sinus rhythm.

The aim was to evaluate the effect of beta-blockers (BB) on the response of heart rate (HR) to 6-min walk test (6MWT) in atrial fibrillation (AF) and whether the AF patients treated with BB have a similar HR response to 6MWT as the AF and sinus rhythm (SR) patients without BB treatment at the same resting HR level. The before-after study involving 74 AF patients was to evaluate the effect of BB treatment (pre-BB and with BB). The comparison study included 74 BB-treated AF patients (with BB), 74 matched AF patients without BB (no BB), and 74 SR patients. The percentage increase amplitude of HR (HR-PIA) in 6MWT was calculated: [(the exercise HR - the resting HR)/(the resting HR)] × 100%. The before-after study showed that BB treatment decreased the resting and mean exercise HR (98.6 ± 15.2 vs. 85.5 ± 11.2 bpm and 121.3 ± 17.3 vs. 109.0 ± 16.7 bpm) during 6MWT. The comparison study demonstrated that against the SR, the AF with BB and no BB groups have higher mean exercise HR-PIA (28.2 ± 17.1% and 22.0 ± 9.6%, vs. 6.9 ± 3.7%) when their resting HR is similar. Moreover, the mean exercise HR-PIA was also significantly higher in the with BB group than in the no BB group. In AF patients with relatively higher resting HR, BB treatment could decrease the resting and exercise HR during 6MWT. However, BB treatment could not effectively attenuate the exercise HR rise as compared with AF without BB treatment, even with similar resting HR levels.

Atrial fibrillation rhythm management: a matter of timing.

Rhythm control in patients with atrial fibrillation (AF) has evolved dramatically in the last decades. Several studies have informed us of the benefits of an early rhythm control strategy and primary rhythm control by catheter ablation (CA). Similarly, several studies have investigated the effects of CA in patients with longer AF duration and more comorbidities, especially heart failure. In the current review, we summarize the current evidence on rhythm control at different time points during the disease course of AF [Table 1 and Central illustration].

ASSOCIATION OF LEFT ATRIAL STRAIN WITH ATRIAL FIBRILLATION IN ACUTE ISCHEMIC STROKE PATIENTS

Background: Acute ischemic stroke due to cardio-embolism associated with atrial fibrillation (AF) has been known to have the highest risk of recurrence and increased patient morbidity and mortality. However, the detection rate of AF rhythm in acute ischemic stroke patients using electrocardiograms and Holter monitoring was still quite low. Functional changes in the left atrium have been associated with an increased incidence of AF. Left atrial strain measurement using speckle tracking echocardiography 2D (STE-2D) can detect left atrial dysfunction associated with AF. Aim: To determine the association between left atrial strain and atrial fibrillation in patients with acute ischemic stroke. Research Methods: This analytical observation study was conducted with a cross-sectional design, using secondary data from medical records at RSUP Dr. Sardjito within January 2020–December 2022 on the population with acute ischemic stroke patients who underwent an electrocardiogram and transthoracic echocardiography examination. Results: During the observation period 142 acute ischemic stroke patients underwent an electrocardiogram and transthoracic echocardiography examinations. A total of 72 patients diagnosed with acute ischemic stroke met the inclusion criteria as study subjects, there were 49 subjects (68%) with sinus rhythm and 23 subjects (32%) with AF rhythm. The left atrial strain value was found to be lower in the AF rhythm group (13,02 ± 8,49%) than in the sinus rhythm group (25,12 ± 8,36%) and was statistically significant (p &lt;0,001). Determination of the optimal cut-off value using the Youden Index obtained a left atrial strain value &lt; 16,25% with a sensitivity of 85,7%, specificity of 73,9%, and area under the curve (AUC) value of 84% (p &lt; 0,001, 95% CI 0,74 – 0,95). The results of the multivariate analysis test showed that left atrial strain was an independent predictor related to the occurrence of AF rhythm (p = 0,001, OR 18,68; 95% CI 3,22 – 108,45). Conclusion: Decreased left atrial strain ​​is associated with atrial fibrillation rhythms in acute ischemic stroke patients. Acute ischemic stroke patients with a left atrial strain value &lt; 16.25% have a higher prevalence of atrial fibrillation rhythm. Keywords: left atrial strain; atrial fibrillation; ischemic stroke; speckle tracking echocardiography