Chronic obstructive pulmonary disease (COPD) is frequently associated with cardiovascular complications, including right heart dysfunction and cardiac arrhythmias. Chronic hypoxia and pulmonary vascular remodeling may lead to structural and electrical cardiac changes. Electrocardiography (ECG) may provide simple markers of right heart strain that could help identify COPD patients at increased arrhythmic risk. To evaluate the association between ECG markers of right heart strain and arrhythmias and to identify independent predictors using multivariable analysis. This cross-sectional observational study included 80 consecutive patients with confirmed COPD treated in a secondary healthcare center. All patients underwent standard 12‑lead ECG and 24-h Holter monitoring. COPD diagnosis and severity were defined according to GOLD criteria. Arrhythmias included atrial fibrillation, supraventricular tachycardia, premature ventricular contractions, and other clinically relevant rhythm disturbances. Patients were divided into two groups: with arrhythmias (n = 40) and without arrhythmias (n = 40). ECG parameters included P pulmonale, right axis deviation (RAD), right ventricular hypertrophy (RVH), T-wave inversion in V1-V3, low QRS voltage and right bundle branch block (RBBB). Multivariable logistic regression analysis was performed adjusting for age, sex, FEV₁, hypertension, diabetes, and cardiovascular risk factors. ECG abnormalities were significantly more prevalent in patients with arrhythmias. P pulmonale was more frequent in the arrhythmia group (55% vs. 20%, p = 0.002), although analysis was restricted to patients in sinus rhythm. RAD (62.5% vs. 20%, p < 0.001), RVH (45% vs. 15%, p = 0.007), T-wave inversion (65% vs. 30%, p = 0.003), and RBBB (60% vs. 20%, p < 0.001) were significantly more common in patients with arrhythmias. Low QRS voltage did not differ significantly between groups (70% vs. 55%, p = 0.20). On multivariable analysis, P pulmonale (OR 3.2, 95% CI 1.3-7.8, p = 0.01) and RVH (OR 2.9, 95% CI 1.1-7.2, p = 0.03) were independent predictors of arrhythmias. ECG markers of right heart strain, particularly P pulmonale and RVH, are independent predictors of arrhythmias in COPD patients. ECG may serve as a simple, non-invasive tool for early risk stratification and identification of patients who may benefit from closer rhythm monitoring. The relatively small sample size and single-centre design may limit the generalizability of the findings.
Left ventricular ejection fraction (LVEF) has not demonstrated reliability in predicting ventricular arrhythmias or appropriate implantable cardioverter defibrillator (ICD) therapy (AICDt). To evaluate the association between left ventricular global longitudinal strain (GLS) and AICDt. One hundred seventy-eight consecutive patients who received ICD implants for primary prevention of sudden cardiac death from 1/16/2015 to 1/26/2022 were followed until 1st appropriate ICD therapy (AICDt) for a ventricular arrhythmia, death, or loss to follow-up. AICDt were physician adjudicated. Covariates included demographic variables (age, sex), clinical risk factors (LVEF, cardiac resynchronization therapy, coronary artery disease, anti-arrhythmic drug use, QRS duration), and variables from the DO-IT model (nonsustained ventricular tachycardia, atrial fibrillation, glomerular filtration rate, peripheral vascular disease, direct oral anticoagulant use, digoxin use, aldosterone antagonist use, and angiotensin converting enzyme inhibitor/angiotensin II receptor blocker use). Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI95) of GLS per 5% decrease (absolute value) for AICDt. Over a mean (standard deviation) follow up period of 5.09 (2.11) years, 44 of the 178 patients (79.77% male, 63.89 (12.89) years of age) in the final cohort experienced AICDt. In patients with coronary artery disease, GLS per 5% decrease (absolute value) was associated with AICDt independent of demographic variables (HR 2.16, CI95 1.09-4.27), clinical risk factors (HR 2.54, CI95 1.16-5.59), and variables from the DO-IT model (HR 3.28, CI95 1.46-7.36). Reduced GLS (absolute value) is an independent risk factor for AICDt in patients with coronary artery disease.
Ventricular arrhythmias (VAs) originating from the coronary cusps with R wave in lead I typically originate specifically from the right coronary cusp (RCC), but are occasionally of left coronary cusp (LCC) origin. We retrospectively analyzed patients who underwent successful initial catheter ablation for VA in either the LCC (N = 41) or RCC (N = 14). Twelve-lead ECG during VA and during sinus rhythm were compared between LCC arrhythmia patients with an R wave in lead I during VA (R(I)-wave group) and those without (non-R(I)-wave group). In LCC cases in whom CT was available, we measured the anatomical axis of the left ventricle in the frontal plane. Among the 41 LCC patients, 9 (22.0%) showed an R wave in lead I in contrast to 100% of the 18 RCC patients. CT imaging was available for 22 LCC patients (53.7%) and revealed a modest correlation between electrocardiographic and anatomical axis (r = 0.64, p = 0.0014). The R(I)-wave group had a significantly more leftward QRS axis during sinus rhythm (2.0° ± 29.6° vs 43.1° ± 31.1°, p = 0.001) and smaller anatomical axis on CT (14.4° ± 16.46° vs 35.8° ± 11.71°, p = 0.004). ROC analysis showed that a QRS axis < 26° best predicted R wave presence in LCC patients. In cases of VA suspected to originate from the aortic cusps with R wave in lead I, the presence of a leftward QRS axis during sinus rhythm suggests mapping should be extended to the LCC.
Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality globally. The co-occurrence of COPD exacerbation and cirrhosis may compound clinical complexity and elevate adverse outcome risks. This study aimed to evaluate the impact of cirrhosis on outcomes among patients admitted with acute exacerbations of COPD. Data were extracted from the Nationwide Inpatient Sample database for the period of 2019 to 2021. Patients hospitalized with acute exacerbations of COPD were identified using ICD-10 codes. The study population was stratified into patients with cirrhosis and those without. The primary outcome was in-hospital mortality. Secondary outcomes included sepsis, hepatic encephalopathy, respiratory failure, cardiac arrest, cardiac arrhythmias, pneumothorax, pulmonary embolism, acute kidney injury, and hospital length of stay. Among 914,498 patients hospitalized with COPD exacerbations, 4.2% had cirrhosis. Cirrhotic patients were younger and had higher in-hospital mortality, longer length of stay, and higher hospital charges compared to noncirrhotics. Cirrhosis was independently associated with increased mortality and a higher risk of sepsis, acute kidney injury, encephalopathy, shock, and prolonged hospitalization. Associations with arrhythmia and cardiac arrest were not statistically significant. Cirrhosis is associated with higher in-hospital mortality and increased risk of complications in patients admitted for COPD exacerbations, contributing to longer hospital stays and higher healthcare costs. Clinical monitoring and tailored management are warranted in this group.
Concealed accessory pathways (CAP) and atrioventricular nodal reentry tachycardia (AVNRT) represent diagnostically challenging forms of paroxysmal supraventricular tachycardia, with conventional sinus rhythm ECGs often failing to reveal characteristic abnormalities. We developed CSPANet, a novel deep learning architecture that integrates a Channel and Spatial Parallel Attention (CSPA) module for enhanced ECG feature extraction. The architecture features parallel processing through two specialized attention mechanisms: a channel attention submodule that adaptively weights clinically significant ECG leads using complementary feature pathways, working in concert with a spatial attention submodule that captures essential morphological patterns through synergistic multi-scale pooling and convolutional feature extraction. In a comparative study of nine classical CNNs, ResNet50 demonstrated superior performance, achieving the highest sensitivity and specificity and validating the efficacy of residual learning for this task. The proposed CSPANet, integrating our novel channel and spatial parallel attention (CSPA) mechanism, achieved a test set accuracy of 92.6%, sensitivity of 79.0%, specificity of 95.0%, and precision of 79.7%, surpassing all other representative attention mechanisms. Ablation studies confirmed the individual and synergistic contributions of the CSPA and Stem modules, with their combined integration yielding the most significant performance gains, including an 11.7% increase in sensitivity and an 8.8% increase in precision over the baseline ResNet20 model. CSPANet's ability to differentiate CAP and AVNRT from sinus rhythm ECGs offers a transformative clinical tool, facilitating optimized ablation planning and enhancing procedural safety. By addressing a key diagnostic gap, this approach underscores the potential of deep learning to refine arrhythmia management.
The precise preprocedural localization of outflow tract premature ventricular contractions (OT-PVCs) remain essential yet challenging, owing to the region's complex and variable anatomy, particularly for left-sided origins. Although numerous electrocardiographic localization algorithms have been proposed, most are constrained by a trade-off between diagnostic accuracy and clinical practicality. QRS notching is a frequently observed but largely overlooked feature in OT-PVCs, and it remains understudied in the context of idiopathic ventricular arrhythmias. This study aims to move beyond a simple analysis of notch distribution across leads by leveraging QRS notching as a functional marker of ventricular activation to enhance site of origin localization. This retrospective observational study included 105 patients who underwent successful catheter ablation for symptomatic OT-PVCs. The cohort consisted of 57 right ventricular outflow tract (RVOT) and 48 left ventricular outflow tract (LVOT) PVCs. All PVCs exhibited a left bundle branch block morphology with an inferior axis, defined by a dominant R-wave in the inferior leads and a QS complex in leads aVL and aVR. Furthermore, each PVC demonstrated a single, reproducible notch with a duration of ≤20 ms. Notch Timing (NT) was defined as the interval from the earliest onset of the global PVC QRS complex to the nadir of the identifiable notch. When notches were asynchronous across the 12 leads, the timing of the latest-occurring notch was recorded for analysis. The diagnostic performance of the NT criterion for differentiating RVOT from LVOT origins was evaluated and compared against the V2S/V3R index using receiver operating characteristic (ROC) curve analysis, with the area under the curve (AUC) serving as the primary metric of comparison. Of 105 patients (45.6 ± 13.4 years, 55% male), 57 had RVOT and 48 had LVOT PVCs. NT robustly differentiated origins, with RVOT PVCs demonstrating significantly later notches than LVOT PVCs (94.3 ± 15.0 ms vs. 74.5 ± 15.6 ms, p < 0.001). An NT >80 ms favored an RVOT origin with 87.7% sensitivity and 68.8% specificity (PPV = 76,9%, NPV = 78,1%, AUC 0.838). The diagnostic performance of NT was comparable to the established V2S/V3R index (AUC 0.828). Characteristic lead distribution patterns augmented localization, though extensive notching across both the inferior and lateral precordial leads was not specific for a free-wall RVOT origin. This study introduces the first structured framework for QRS notch analysis-defining its characteristics, timing, and distribution-to improve arrhythmia localization. This represents a shift from descriptive morphology to mechanistic interpretation, where a novel notch timing metric robustly discriminates RVOT from LVOT origins by quantifying delayed transeptal conduction.
Disparities in arrhythmia care are increasingly recognized, yet remain incompletely characterized across the patient pathway. This European Heart Rhythm Association (EHRA) survey explored clinician-reported perceptions of inequity across diagnosis, pharmacological management, procedural referral, and follow-up. A 30-question survey was disseminated via the EHRA between November 2025 and January 2026, with 212 responses from professionals across 35 countries. Respondents were predominantly consultant electrophysiologists (67.5%), with 39.6% identifying as female. Most (68.4%) reported no prior training in equity or inclusive care. Across the arrhythmia care pathway, disparities were most frequently attributed to patient vulnerability, particularly cognitive impairment (72.5%), age >80 years (63.8%), and mental health disease (61.3%). Differences related to socioeconomic status, language, and other social factors were also commonly reported. Female sex and minority ethnic background were each reported to influence care in 24.1% of responses. Age >80 years was consistently identified as the strongest determinant of disparities in referral, diagnosis, and outcomes, influencing referral for arrhythmia evaluation (65.8%), catheter ablation (77.9%), and outcomes following ablation (68.1%). Socioeconomic and ethnic factors showed more modest but consistent effects, while sex-based differences were less frequently reported. However, female respondents were more likely than male respondents to report delayed referral (female respondents: 41.8%; male respondents: 19.8%) and late or incorrect diagnosis (49.4 vs. 15.8%) in female patients, as well as delayed referral for catheter ablation (36.5 vs. 10.3%) and device implantation (23.0 vs. 7.0%). Only one-third of respondents (33.3%) felt that current international guidelines adequately address diversity, equity, and inclusion in arrhythmia care. Clinicians perceive disparities in arrhythmia care across multiple patient and social factors. Whilst age and vulnerability were most frequently perceived to influence care, sex and ethnicity were also recognized by a substantial proportion of respondents. Perceptions varied according to respondent characteristics, with female clinicians more likely to report disparities amongst female patients. Limited training and institutional frameworks highlight opportunities for targeted interventions.
Catheter ablation for atrial fibrillation (AF) is one of the most common cardiovascular procedures being performed worldwide. Despite the large body of evidence of its effectiveness, with a single exception, prior ablation studies were largely unblinded trials. Accordingly, residual concerns remained about placebo effects, both for AF recurrence and, in particular, on subjective outcomes such as quality of life or anxiety. Here, we compared pulsed field ablation (PFA) with a sham procedure to treat patients with symptomatic AF. This prospective, sham-controlled, single-blind, randomized clinical trial with blinded end-point assessment enrolled patients with AF that was highly symptomatic (Atrial Fibrillation Effect on Quality-of-Life score <50). Patients were assigned 1:1 to PFA or a sham procedure. All participants received implantable cardiac monitors for continuous rhythm monitoring during follow-up. The 6-month co-primary outcomes were (1) time to first recurrence of atrial tachyarrhythmia and (2) changes from baseline in Atrial Fibrillation Effect on Quality-of-Life scores compared between groups. Secondary outcomes were AF burden and psychological distress (assessed by the Hospital Anxiety and Depression Scale [HADS]). Patients (n=60) were randomized to PFA or sham. At 6 months, the first co-primary end point of AF recurrence was met in 2 patients (6.7%) who underwent PFA and 25 patients (83.3%) who underwent sham (posterior hazard ratio, 19.6 [95% bayesian credible intervals, 6.7-76.9]; posterior probability of superiority >0.99). For the second co-primary end point, Atrial Fibrillation Effect on Quality-of-Life scores showed greater improvement from baseline with PFA than sham (improved by 43.9+18.1 points versus 11.3+27.9 points; posterior median difference, 32.6 [95% bayesian credible interval, 20.2-44.9]; posterior probability of superiority >0.99). AF burden at 6 months was significantly lower in the PFA than the sham group (0 [0-0] versus 0.43 [0.04-3.47]; between group median difference, -0.39 [95% credible interval, -2.5 to -0.1], posterior probability of superiority >0.99). The Hospital Anxiety and Depression Scale score changed by -4 points (-7.8 to -2.0) with PFA and by -0.5 (-4.5 to 1.0) with sham (group median difference, -3.5 [95% credible interval, -6.0 to -1.0]; posterior probability of superiority >0.99). In patients with AF, PFA was superior to sham in reducing arrhythmia recurrences and burden and improving quality of life and AF-associated psychological distress. URL: https://www.clinicaltrials.gov; Unique identifier: NCT05717725.
Women are at higher risk of serious ventricular arrhythmias, including torsades de pointes, when repolarization reserve is reduced, but sex-stratified mechanisms and quantitative risk assessment remain challenging. We aimed to develop scalable, tissue-scale, sex-aware ventricular virtual populations to quantify and explain sex differences in inherited and acquired proarrhythmic susceptibility. We constructed male and female virtual cohorts using a one-dimensional ventricular cable model with pseudo-electrocardiogram (pseudo-ECG), integrating sex-specific ionic conductance backgrounds and acute sex-hormone modulation. Virtual populations were filtered under multi-condition stress tests and calibrated to clinical corrected QT interval (QTc) distributions. We generated long QT syndrome types 1-3 (LQT1-3) cohorts, simulated sympathetic stress, and performed virtual drug trials for 109 compounds using multichannel block profiles at 1× effective free therapeutic plasma concentration. Proarrhythmic risk was defined by tissue-scale instability events (premature ventricular complexes, T-wave alternans, or repolarization failure). Drivers were analysed using regression and channel-sensitivity analysis, and clinical 24 h concentration-ECG data after dosing were used for external validation. The female cohorts exhibited higher simulated event risk across long QT syndrome subtypes and across multichannel drug block profiles, including drugs with <10 ms mean QTc prolongation. Female-to-male risk ratios tracked clinical risk categories. Simulated QTc time-courses and concentration-QTc trends agreed with 24 h clinical ECG data for key reference drugs. Sex-aware tissue-scale virtual populations enable in silico trials that quantify proarrhythmic risk beyond mean ΔQTc, provide mechanistic drivers, and support sex-informed cardiac safety evaluation and monitoring strategies.
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with reduced quality of life and increased healthcare utilisation. AF is increasingly recognised as a manifestation of an underlying cardiometabolic disease process, with obesity and related metabolic risk factors contributing to its development and progression. Consequently, upstream risk factor modification, including structured weight management, has emerged as a potential strategy to improve AF outcomes. While dietary and exercise interventions have been studied individually, the effectiveness of programmes combining both components has not been systematically reviewed in patients with AF who are overweight or obese. This review aims to assess the impact of combined nutritional and physical activity interventions on AF-related outcomes. A systematic search will be conducted in MEDLINE, CINAHL, EMBASE and EMCARE from database inception to April 2026. Eligible studies will include randomised controlled trials, quasi-experimental studies and controlled cohort studies evaluating combined dietary and physical activity interventions in adults with AF who are overweight or obese. The primary outcome will be AF symptom burden measured using validated instruments. Secondary outcomes will include quality of life, anthropometric measures, metabolic parameters and AF arrhythmia burden. Risk of bias will be assessed using RoB 2 and Risk of Bias in Non-randomised Studies of Interventions. Where appropriate, meta-analysis will be performed using random-effects models. Ethical approval is not required. Findings will be disseminated through peer-reviewed publications and scientific meetings. Open Science Framework (OSF; https://doi.org/10.17605/OSF.IO/HCUZ3).
Cryoablation is an established treatment for atrial fibrillation (AF), offering effective rhythm control and symptomatic improvement. However, short-term trajectories of quality-of-life (QoL) recovery-particularly regarding age- and sex-related differences-remain insufficiently characterized. This study evaluated patterns of functional and emotional improvement within 3 and 6 months after cryoablation. A prospective observational cohort of 150 patients undergoing cryoablation for AF was analyzed. QoL was assessed using the 36-item short form (SF) (Physical and Mental Component Scores PCS and MCS) survey at baseline, 3 months, and 6 months. Significant improvements were observed across all SF-36 (57.5 at baseline to 77.1 at 3-months and 80.1 at 6-months, p < 0.001), PCS and MCS between baseline and follow-up (main effect of time p < 0.001). An age × time interaction showed that younger patients (≤ 65 years) demonstrated greater functional gains both in 3 and 6 months compared to older adults (p < 0.001 for all). A sex × time interaction was also noted for SF-36 (p = 0.046) and PCS (p = 0.038), reflecting a trend for a more rapid improvement in men versus women. These sex differences were non-significant after Bonferroni adjustment. Multivariable regression confirmed younger age as the strongest independent predictor of improvement (β = 18.2, p < 0.001), followed by paroxysmal AF type and baseline ejection fraction. Cryoablation leads to substantial QoL improvements. While age is a robust independent predictor of recovery, sex-specific differences in physical and emotional trajectories appear as notable trends requiring further investigation. These findings emphasize the need for individualized post-procedural counseling and follow-up tailored to demographic recovery profiles.
Extracellular vesicles (EVs) circulate in blood and may serve as disease biomarkers. However, in atrial fibrillation (AF), reliable circulating biomarkers remain limited. Conventional quantification of EVs requires cumbersome extraction procedures that can reduce quantitative accuracy. We investigated whether laser diffraction (LD) enables accurate and reproducible measurement of EV-sized particles in blood plasma without an extraction process. LD was used to measure particle size and concentration of synthetic liposomes and plasma-derived EV fractions, and the results were compared with nanoparticle tracking analysis (NTA). Particles in plasma were then measured by LD with and without an extraction process, and the impact of dietary conditions was evaluated. Finally, particle concentrations in fasting plasma were compared between 20 controls without AF and 20 patients with AF. For both synthetic liposomes and extracted EV fraction, LD showed quantitative accuracy comparable to NTA, with higher reproducibility. LD-based measurement in plasma without an extraction process produced a size distribution profile similar to that obtained after extraction, whereas the peak particle concentration decreased after extraction, suggesting partial particle loss during processing. Postprandial samples showed contamination by chylomicrons and very-low-density lipoproteins, which shifted the size distribution toward larger particles and interfered with plasma measurement. Using fasting plasma, the concentration of EV-sized particles measured by LD was significantly higher in AF patients than in controls (p = 0.0225). LD enables accurate and highly reproducible quantification of EV-sized particles in fasting plasma without an extraction process and may support proof-of-concept biomarker assessment in AF.
Evidence for prone positioning in post-cardiac surgery acute respiratory distress syndrome (ARDS), especially after acute type A aortic dissection (ATAAD) repair, is extremely limited. Clinicians remain uncertain about its safety, feasibility, and the optimal timing of initiation in this hemodynamically vulnerable population. To evaluate the effectiveness and safety of prone positioning for moderate-to-severe ARDS (MS-ARDS) after ATAAD repair, and to determine whether early initiation (≤ 48 hr) provides additional clinical benefit. A retrospective, single-center cohort study conducted in a tertiary cardiovascular center. Seventy-eight adults with MS-ARDS after ATAAD surgery were included: 58 received prone positioning and 20 remained supine. Primary outcomes were duration of mechanical ventilation (MV) and postoperative ICU length of stay (LOS). Secondary outcomes included hospital LOS, hospitalization cost, and 28- and 90-day mortality. Adverse events were systematically captured using prespecified hemodynamic and respiratory categories. Preoperative and perioperative characteristics were comparable between groups. In the prone cohort, the Pao2/Fio2 improved from 92.67 ± 21.04 to 152.45 ± 64.28 mm Hg at 4 hours (p < 0.001), demonstrating rapid oxygenation gain. Patients were further stratified by timing of intervention: early prone positioning (EPP: ≤ 48 hr from ARDS onset) and delayed prone positioning (DPP). EPP was associated with a significantly shorter duration of MV 5.03 ± 1.87 days compared with DPP 8.32 ± 4.73 days and the supine group 7.51 ± 4.08 days (p = 0.002). No increase in adverse events was observed, and no episodes of malignant arrhythmia or cardiac arrest occurred. Prone positioning for MS-ARDS after ATAAD repair was feasible, safe, and rapidly improved oxygenation. Initiation within 48 hours was associated with a clinically meaningful reduction in ventilation duration. These findings support early, protocolized prone positioning in selected postoperative ATAAD patients and justify further evaluation in prospective trials.
Atrioventricular nodal reentrant tachycardia (AVNRT) is a common supraventricular tachycardia in children and is routinely treated with catheter-based slow-pathway ablation. Procedural safety and radiation exposure reduction are paramount in the pediatric age group, which can be accomplished with 3D electroanatomic (EAM) mapping systems. Evaluation of zero-fluoroscopy radiofrequency (RF) slow-pathway ablation outcomes for AVNRT in patients ≤ 21 years and perform a comparative analysis with the published data on cryoablation, fluoroscopy-guided RF ablation in children, and fluoroless RF ablation in adults. We performed a retrospective cohort study of consecutive patients aged ≤ 21 years who underwent RF catheter ablation for AVNRT between June 2016 and September 2025 using the CARTO EAM system. The cohort included 125 patients (71 females) with a median age of 14.9 years (range 6.0-21) and median weight of 57.4 kg (IQR 48-68). Non-steerable long sheaths were utilized in the majority of patients. Fluoroscopy time was 0 min in all cases. Acute success was achieved in all patients, with no procedural complications. Median procedure time was 121 min (102-151). Among 117/125 patients, with follow-up at a median duration of 36 months, there was no recurrence. In this consecutive cohort of 125 patients aged ≤ 21 years, zero-fluoroscopy RF slow-pathway modification for AVNRT was performed with complete acute success, no major complications, and no recurrences. Our data support fluoroless RF ablation as an effective and durable strategy for AVNRT in pediatric and young adult patients at experienced centers.
Autonomic nervous system (ANS) dysfunction is implicated in sleep-disordered breathing (SDB) and atrial fibrillation (AF); however, diurnal patterning of ANS function in SDB is unclear. We hypothesize diurnal variation of heart rate variability (HRV) in paroxysmal AF (PAF) in SDB and alteration by continuous positive airway pressure (CPAP). Data from the Sleep Apnea and Atrial Fibrillation Biomarkers and Electrophysiologic Atrial Triggers (SAFEBEAT) study including 7-24 days of electrocardiography (ECG), concomitant actigraphy and polysomnography at baseline and 3 months post-CPAP initiation were analyzed. Linear mixed-effects models were used to assess (1) SDB: apnea hypopnea index (AHI), hypoxia (%sleep time with SaO2 < 90% and nadir SaO2) and (2) diurnal average HRV in 2 domains: frequency domain (sympathovagal) with low-frequency (LF) power (LFP), high-frequency (HF) power (HFP), LF/HF ratio (LHR), and time domain with mean of normal R-R interval (MNN), standard deviation of NN intervals (SDNN), Poincare plot standard deviation short-term and long-term variability (SD1, SD2) and effect of CPAP. All results were adjusted for age, sex, race, BMI, and use of antihypertensive, antiarrhythmic, and atrioventricular nodal blockade medications. In 44 869 5-min epochs from 109 participants with SDB and PAF, associations of AHI and LFP, nadir SaO2 with sympathovagal measures (LFP, LHR) and time domain measures (SDNN, SD2) were observed during wakefulness. Sleep-wake interactions were observed for multiple HRV measures, with associations generally more evident during wakefulness. From baseline to follow-up after CPAP, wakefulness HRV measures showed an increase in MNN and decreases in SDNN, RMSSD, CV, SD1, and SD2. During sleep, MNN, SD2, and LHR increased. Autonomic measures exhibited diurnal variation in moderate-severe SDB and were influenced by CPAP. Association with SDB severity was more pronounced during wakefulness, providing key insights into likelihood of sustained chronobiologic electrophysiological remodeling.
Atrial fibrillation (AF), the most prevalent cardiac arrhythmia, affects 2% to 4% of the global adult population and is associated with an increased risk of stroke. Early diagnosis of AF and atrial flutter (AFL) is crucial due to their association with stroke risk and the challenge posed by their often asymptomatic and episodic nature. Traditional electrocardiogram (ECG) interpretation requires substantial expert input and can be challenging, especially with poor-quality ECGs. This study aimed to evaluate the performance of a deep neural network (DNN) model in detecting AF/AFL from a large, heterogeneous set of long-term ambulatory ECG recordings, including clinical data collected over 6 months at a university hospital, and assess its effectiveness in a setting reflecting the diversity and complexity of real-world clinical data. The research combined public datasets totaling 10,248 patients, ECG data from our previous studies (648 patients), and authentic long-term ECG recordings from 4346 patients at Kuopio University Hospital for development of the DNN model. Its clinical accuracy and generalizability were assessed using a separate test dataset consisting of 1039 pseudonymized long-term ECG recordings from 1010 patients, all thoroughly reviewed and annotated by experts. The DNN model demonstrated high effectiveness, achieving 96.4% sensitivity and more than 99.99% specificity for time-level AF and AFL detection. At the recording level, it identified AF and AFL with 100% sensitivity and 98.77% specificity, producing false positives in only 1.2% (11/897) of recordings, of which 81.8% (9/11) had other non-AF/AFL arrhythmias. The model maintained high performance across diverse patient characteristics, including varying ages, comorbidities, coexisting arrhythmias, and poor-quality ECG recordings. The results demonstrate that the proposed DNN model may support automated screening for AF and AFL in long-term ambulatory ECG recordings and may reduce manual review workload in clinical practice.
How to reduce the occurrence of in-hospital cardiac arrest (IHCA), screen potential IHCA patients, and advance the treatment of IHCA are urgent problems to be solved in clinic. In this study, we tried to develop a model to predict whether patients will develop IHCA based on the data of patients who have just been admitted to hospital and evaluate the influence of different feature selection methods on machine learning (ML) models. A total of 25 149 patients were included in the study; 320 developed IHCA. We chose three feature selection methods (Student's t-test and Chi-square test, regression analysis and correlation analysis) and four ML models (AdaBoost, XGBoost, Random Forest, and Logistic Regression). Each ML model was trained and evaluated using raw and feature-selected data; as a result, we got 16 models. AUROC, AUPRC, accuracy, recall, precision, and specificity are used to evaluate the model. The XGBoost model has the best performance with an AUROC of 0.987 (95% CI 0.984-0.988), an AUPRC of 0.763, an accuracy of 0.992, a recall of 0.695, a precision of 0.723, and a specificity of 0.996. The most significant predictors are age, albumin, sinus arrhythmia, activated partial thromboplastin time, and protein. Different feature selection methods have different effects on different ML models. The predictive model developed using the XGBoost algorithm is the best predictor of whether patients will develop IHCA.
T-wave amplitude variability (TAV), a marker of beat-to-beat ventricular repolarization instability, has been proposed as a potential risk marker for adverse cardiovascular outcomes, but its prognostic value remains unclear. This meta-analysis aimed to quantitatively synthesize evidence on the association between elevated TAV and adverse cardiovascular outcomes. A systematic literature search of PubMed, Embase, and the Cochrane Library was conducted. Observational studies reporting adjusted effect estimates for the association between TAV and adverse cardiovascular outcomes were included, and separate meta-analyzes were conducted according to effect measures (hazard ratios [HRs] or odds ratios [ORs]) and exposure definition. Effect estimates were pooled using a random-effects model. Statistical heterogeneity was assessed using the Q statistic and I 2. Seven studies involving 1366 patients were included. HR-based analyzes (n = 3) showed that elevated TAV was significantly associated with an increased risk of adverse outcomes, including mortality and ventricular tachyarrhythmias (pooled HR 2.51, 95% CI 1.57-4.00; I 2 = 7%). In contrast, OR-based analyzes showed no statistically significant association between TAV and ventricular tachyarrhythmias, whether evaluated as categorical (high vs. low TAV: pooled OR 3.82, 95% CI 0.87-16.84; I 2 = 75%) or continuous variable (per 1-μV increase: pooled OR 1.11, 95% CI 0.94-1.30; I 2 = 70%). Elevated TAV is associated with an increased risk of adverse cardiovascular outcomes in HR-based analyzes, supporting its potential utility as a marker of repolarization instability for longitudinal risk stratification. In contrast, its association with ventricular tachyarrhythmias was not significant in OR-based analyzes, which showed substantial heterogeneity. Trial Registration: PROSPERO: CRD420251171782.
This study aimed to explore the predictors of disease severity in patients with coronavirus disease 2019 (COVID-19) using ambulatory electrocardiographic markers (AECG-Ms), which are prognostic predictors of cardiac death, as well as echocardiography and laboratory parameters. A prospective cohort study was conducted using data from 70 patients diagnosed with COVID-19 and admitted to the National Defense Medical College Hospital between January 2021 and December 2023. A high-resolution Holter electrocardiogram recorder was attached to all patients for 24 h within 48 h of admission, and AECG-Ms were measured. Laboratory tests and echocardiography were also performed. Logistic univariate analysis revealed that the T-wave alternans (TWA) positivity rate was significantly higher in the fatal event group (all-cause mortality and onset of sustained ventricular tachycardia or ventricular fibrillation) than in the non-fatal event group. Kaplan-Meier curves at 30 days after admission showed a significant worsening in the survival rate of the TWA and late potential positive groups (log-rank test, p < 0.0001) compared with the other groups. In patients with COVID-19 without obvious cardiac disease, AECG-Ms were highly positive. The study findings may allow easy and rapid prediction of prognosis at the bedside of patients with COVID-19.