Sleep bruxism as a potential modifier of autonomic function and heart rate variability in patients with obstructive sleep apnea.

Clinical significance of fragmented QRS in isolated hypertension: Associations with ventricular arrhythmia burden and autonomic dysfunction.

Cardiac arrhythmia during cold-water immersion: a self-controlled field study with extended rhythm monitoring.

Chronic heart failure (CHF) is a condition affecting millions worldwide, characterized by the heart's reduced ability to pump blood efficiently. Conventional diagnostics, such as imaging and ECG assessments, can be time-consuming and expensive, often identifying CHF only after significant progression. Early detection is crucial for improving treatment options and reducing healthcare costs. Heart rate variability (HRV), which measures the variation in time intervals between heartbeats, is emerging as a non-invasive and cost-effective biomarker for CHF detection. HRV reflects the autonomic nervous system's regulatory functions, often impaired in CHF patients. This study aims to assess advanced HRV measures for earlier CHF detection. The research involved examining CHF patients (N = 934, Age 65 ± 12) compared to healthy controls (N = 274, Age 43 ± 17). Data was sourced from Physionet and the Telemetric and Holter ECG Warehouse, with RR interval (RRI) data extracted from 24-h Holter recordings. The study utilized dynamical detrended fluctuation analysis (DDFA), which considers changes in RRI correlations over time and scale, resulting in scaling exponent α(t,s). This was further aggregated into scale and heart rate (HR)-dependent forms, α(HR,s), classified using XGBoost ensemble method with 10-fold nested cross-validation. The classifier achieved 97% sensitivity and 90% specificity for distinguishing between CHF and control groups. Sensitivity and specificity remained consistent across subgroup analyses based on beta blocker medication and NYHA class. This method demonstrated high classification accuracy, suggesting potential utility for early CHF detection, independent of CHF severity.

Factors associated with one-year maintenance of sinus rhythm after successful electrical cardioversion of persistent atrial arrhythmias in patients with cardiac implantable electronic devices

Detection of Atrial Fibrillation via Adhesive Single-Lead ECG vs. Holter Monitoring in Embolic Stroke of Undetermined Source: The AVANT-GARDE Trial.

Impact of pulsed field ablation on outcome in obese patients undergoing pulmonary vein isolation for atrial fibrillation

Non-invasive Predictors of recurrence after catheter ablation for idiopathic PVCs

Atrial fibrillation (AF) burden and longest duration are important predictors of heart failure and embolism. However, burden-specific detection rates on 7-day Holter ECG remain unclear. Among 25,817 recordings, 2,289 cases of paroxysmal AF and 571 cases of persistent AF were identified. Low-burden AF was common, and 7-day monitoring substantially improved detection, particularly for AF burden <10% (2.6-fold increase vs. 24-h). AF burden correlated with the longest duration (r=0.79). 7-day Holter monitoring improved low-burden AF detection and confirmed a strong correlation between AF burden and longest duration.

Incomplete low-voltage area (LVA) ablation may confound evaluation of its true efficacy in persistent atrial fibrillation (AF). This post hoc subanalysis of the multicenter randomized SUPPRESS-AF trial assessed the impact of complete LVA ablation. Patients with persistent AF and a left atrial (LA) LVA ≥5 cm2after pulmonary vein isolation were randomized to LVA ablation or no additional ablation. The primary endpoint was freedom from AF or atrial tachycardia recurrence, assessed by 24-h Holter and twice-daily electrocardiogram recordings. Outcomes were compared among 3 groups: no LVA ablation; complete LVA ablation; and incomplete LVA ablation. Among 341 patients, 170 underwent LVA ablation, including 37 with incomplete. LVA size was significantly larger in the incomplete than complete ablation group (22.0 vs. 12.2 cm2; P<0.001). Incomplete LVA ablation was not associated with increased arrhythmia recurrence. Arrhythmia-free survival did not differ significantly between the complete and no LVA ablation groups (hazard ratio [HR] 0.80; 95% confidence interval [CI] 0.56-1.13), including after propensity score matching (HR 0.76; 95% CI 0.51-1.15). However, a trend towards greater benefit of complete LVA ablation was observed with increasing LA diameter (Pinteraction=0.099). Leaving LVA ablation incomplete to avoid complications appears reasonable. Although complete LVA ablation showed no overall superiority, LA enlargement may represent a clinically relevant factor for patient stratification.

Hemodynamic depression is common after carotid artery stenting (CAS), but whether its two phenotypes, persistent hypotension and bradycardia, reflect shared or distinct autonomic responses remains unclear. We aimed to characterize perioperative autonomic changes associated with these outcomes via continuous Holter monitoring. In this prospective, single-center cohort, consecutive CAS patients were enrolled, and a prospective subcohort underwent Holter monitoring from 24 hours before to 24 hours after stenting. Sympathetic activity index (SAI) and parasympathetic activity index (PAI) were derived from heartbeat series to reflect autonomic modulation. Persistent hypotension was defined as systolic blood pressure<90 mmHg or vasopressor requirement for ≥6 hours, and persistent bradycardia as heart rate<60 beats/min for ≥6 hours within 24 hours after CAS. Exploratory mediation-style analysis examined the extent to which autonomic changes accounted for each outcome. Among 735 enrolled patients, 301 had valid recordings for autonomic analysis. In this monitored subcohort, CAS was associated with a reciprocal autonomic shift, with decreased SAI and increased PAI (both p<0.001). Reduced SAI statistically explained a larger proportion of the modeled association with bradycardia (88.9%; residual association p=0.570), whereas autonomic indices explained only a modest proportion of the modeled association with hypotension (SAI 20.0%; PAI 16.1%; both mediation p<0.001), with a significant residual association remaining (p<0.001). CAS was associated with sympathetic withdrawal and parasympathetic activation. These exploratory findings suggest that bradycardia was more tightly associated with heart rate-derived autonomic changes than hypotension, which was less fully captured by SAI/PAI and may involve additional factors.

Atrial fibrillation (AF) is a major predictor of heart failure, stroke, and mortality. Traditional Holter monitors and event recorders are limited by short recording times. Wearable electrocardiographic (ECG) and photoplethysmographic (PPG) devices enable continuous monitoring and large-scale AF screening. This review assesses their diagnostic performance, clinical usefulness, and implementation challenges. Following PRISMA guidelines, PubMed, Embase, and Web of Science were searched for studies from 2010-2025. Included studies had ≥30 participants and reported AF detection accuracy or clinical outcomes. Studies evaluating PPG devices required ECG verification as the reference standard. Wearable ECG patches showed high sensitivity (92-98%) and specificity (85-97%) and detected more AF episodes than short-duration Holter monitoring. PPG-based smartwatches demonstrated moderate-to-high accuracy in irregular pulse detection, further improved by AI-assisted algorithms. Limitations included motion artifacts, false positives, adherence issues, clinician data burden, and limited evidence for stroke prevention. Wearable ECG devices are reliable for clinical AF detection. PPG-based devices are best used for screening, with subsequent ECG confirmation according to international AF management guidelines.

Fetal sinus bradycardia (FSB) is usually a benign antenatal finding but it can be a marker of an underlying serious condition that manifests in later life. The aim of this study was to report the antenatal course and postnatal outcome of FSB. This study was a retrospective review of all cases of persistent FSB, defined as a fetal heart rate (FHR) < 3rd percentile for gestational age (GA) with 1:1 atrioventricular conduction on at least two consecutive fetal echocardiograms, diagnosed between January 2014 and December 2024 at the Brompton Centre for Fetal Cardiology, London, UK. Cases of isomerism were excluded, but fetuses with congenital heart disease (CHD) and normal situs were included. Antenatal data retrieved included GA at diagnosis, indication for referral, family history of any CHD or inherited arrythmia, maternal history of medication or medical conditions, fetal echocardiographic findings and sequential FHR measurements. Postnatal data included the results of 12-lead electrocardiography, echocardiography, 24-h Holter monitoring, genetic testing and final diagnosis. The final cohort comprised 34 cases with persistent FSB, resulting in 33 live births and one termination of pregnancy for multiple extracardiac anomalies. Indications for referral included fetal bradycardia (n = 20), suspected CHD (n = 5), maternal anti-Ro antibodies (n = 1) and a family history of long QT syndrome (LQTS) (n = 5), cardiomyopathy (n = 2) or CHD (n = 1). Associated structural cardiac abnormalities were present in seven fetuses, including biventricular hypertrophy related to hypothyroidism (n = 2), hypertrophic cardiomyopathy (n = 1), hypoplastic left heart syndrome(n = 1), bilateral superior vena cava (n = 1), left ventricular non-compaction (LVNC) (n = 1) and a small ventricular septal defect (n = 1). Postnatal diagnoses included LQTS (n = 10), sinus-node dysfunction (SND) (n = 6), LVNC (n = 2), Albright's hereditary osteodystrophy with hypothyroidism (n = 2), histiocytoid cardiomyopathy (n = 1), catecholaminergic polymorphic ventricular tachycardia (n = 1) and myotonic muscular dystrophy (n = 1). The remaining 11 cases were classified as 'normal'. Genetic reports were available in 22 patients, of whom seven had mutations in KCNQ1, three in KCNH2, two in GNAS1 and one each in NDUFB11, RYR2, CDH7 and DMPK; one patient had a variant of unknown significance and five had normal results. Cascade testing detected affected family members in 2/4 de-novo cases of LQTS and in the one case of catecholaminergic polymorphic ventricular tachycardia. Only one neonate, who had SND (anti-Ro related), required a pacemaker at 4 years of age. FSB could be the first manifestation of serious underlying cardiac conditions, including inherited arrhythmia syndromes, cardiomyopathy and SND, and needs careful antenatal and postnatal evaluation. Cascade testing allows the identification of potentially at-risk first-degree relatives, thereby enabling prompt intervention and appropriate management. © 2026 International Society of Ultrasound in Obstetrics and Gynecology.

Atrial standstill represents a rare cardiac arrhythmia characterised by the complete absence of atrial electrical and mechanical activity. Early diagnostic recognition coupled with comprehensive genetic counselling assumes paramount importance. Herein, we report a rare case of a patient who presented with bradycardia at an early age and demonstrated aggressive atrial standstill during a pacemaker upgrade, which challenged the therapeutic strategy. A 5-year-old girl was initially diagnosed with bradycardia. Holter monitoring confirmed severe bradycardia with prolonged sinus arrest episodes. Subsequently, the patient underwent single-chamber pacemaker implantation. During a planned dual-chamber upgrade at age 11, despite systematic exploration of multiple anatomical sites within the right atrium, adequate atrial capture could not be achieved. Intracardiac electrophysiological assessment demonstrated a complete absence of electrical activity in the bi-atrium. While speckle-tracking echocardiography revealed mildly reduced global longitudinal strain with impairment noted in the lateral myocardial segments, indicating potential injuries from ventricular demand pacing. Genetic test identified a compound heterozygous variant of SCN5A c.2431C>T and c.2893C>T. The protein structure of SCN5A has been built and named AF-P21333-F1, and the molecular function of the variant site has been annotated. Additionally, murine scRNA-seq data (GSE132658) revealed cardiac Scn5a expression is confined to the conductive bundles and fibres rather than cardiomyocytes, and the loss-of-function caused aggressive atrial standstill. This case provides valuable insights into genotype-phenotype correlations in SCN5A-associated atrial standstill, emphasises the importance of comprehensive electrophysiological assessment during device implantation, and underscores considerations for physiological pacing strategies in paediatric patients requiring lifelong device dependency.

Conflicting data exist about whether race/ethnicity affects risk of atrial fibrillation (AF) but less is known about how race/ethnicity is associated with AF burden in paroxysmal AF. We identified members of Kaiser Permanente Northern and Southern California healthcare systems who underwent 14-day continuous ambulatory electrocardiographic monitoring (ZIO® XT Patch, iRhythm Technologies, Inc.) between October 2011-October 2016 and had paroxysmal AF during monitoring. Self-reported race/ethnicity, other demographics, and stroke risk factors were obtained from electronic health records. Multivariable models evaluated the association of race/ethnicity with log-transformed AF burden (i.e., percentage of analyzable time in AF). Among 1069 adults with paroxysmal AF confirmed on continuous electrocardiographic monitoring, mean age was 69.1 years, with 45% women, 4% Black, 13% Asian/Pacific Islander, and 11% Hispanic. Median AF burden was 4% (IQR:1-13%) and varied by race/ethnicity: White (3.6%), Black (1.4%), Asian/Pacific Islander (5.7%), Hispanic (2.5%). In multivariable analyses, compared to White patients, Black patients had lower AF burden (adjusted relative estimate: -58%, 95%CI:-78% to -21%), while Asian/Pacific Islander patients had higher AF burden (adjusted relative estimate: 57%, 95%CI:7% to 130%). These findings have implications about the utility of extended continuous electrocardiographic monitoring for better understanding AF and for personalizing management across diverse populations.

BackgroundBrachycephalic obstructive airway syndrome (BOAS) affects the upper airways of brachycephalic dogs and might alter heart rate variability (HRV).Hypothesis/ObjectivesThis study aimed to evaluate HRV in dogs with BOAS during wakefulness and sleep.AnimalsForty-six client-owned dogs: 34 brachycephalic (with and without BOAS) and 12 non-brachycephalic controls.MethodsA prospective cross-sectional study utilizing 24-h Holter monitoring and segments recorded during wakefulness and sleep. The evaluated variables included heart rate, mean RR interval, the longest sinus pause, and HRV indices calculated over 24 h, as well as during segments of wakefulness and sleep: corrected standard deviation of NN intervals (cSDNN), corrected root mean square of successive differences (cRMSSD), the vagal tone index (VVTI), and Poincaré plot analysis.ResultsIn the 24-h Holter analysis, BOAS dogs showed significantly higher values than controls, particularly in cSDNN (0.365 [IQR: 0.306-0.465] vs 0.246 [IQR: 0.208-0.359] ms, P = .0058) and cRMSSD (0.476 [IQR: 0.409-0.599] vs 0.312 [IQR: 0.259-0.462] ms, P = .0119). Sleep was associated with higher cSDNN, cRMSSD, and VVTI in all groups (StateSleep estimates: 0.105 [95% CI, 0.062-0.149], 0.426 [95% CI, 0.264-0.588], and 1.758 [95% CI, 1.378-2.139], respectively; all P < .001), with no significant group-by-state interaction for these variables. Presence of BOAS was moderately correlated with the longest sinus pause (r = 0.4197, P = .0023), cSDNN (r = 0.4600, P = .0006), and cRMSSD (r = 0.4214, P = .0018).Conclusions and clinical importanceThe presence of BOAS influences autonomic modulation more than the dogs’ craniofacial conformation. Differences in HRV were more pronounced in awake dogs, likely due to chronic respiratory alterations and intermittent hypoxia.

BackgroundPreparticipation cardiovascular evaluation (PPE) is widely recommended to reduce the risk of sudden cardiac events in athletes; however, the optimal screening protocol remains debated. Although resting ECG and echocardiography are commonly used, intermittent arrhythmias may remain undetected.ObjectiveTo assess whether the addition of 24-hour ambulatory ECG (Holter) monitoring, including during sleep and training, increases the detection of potentially pathological cardiovascular findings.Design and settingsThis observational cross-sectional study included athletes (aged 14–42 years) from a Spanish elite multisport professional club undergoing pre-season PPE during the 2023–2024. All athletes completed a standardised evaluation comprising medical history and physical examination, resting 12-lead ECG, transthoracic echocardiography and 24-hour wireless Holter monitoring performed during daily activities including at least one training session. Detection rates of potentially pathological findings were compared across screening test combinations.ParticipantsOf 343 athletes recruited, 299 (79.6% male; mean age 22 years) were included in the final analysis.ResultsPotentially pathological findings prompting further evaluation were identified in 34 athletes (11.3%). The addition of any single test to medical history and physical examination significantly increased detection rates. Holter monitoring identified more intermittent arrhythmic events, particularly during exercise or sleep, whereas resting ECG more frequently detected repolarisation abnormalities. Echocardiography primarily contributed to the identification of structural abnormalities. Following a comprehensive evaluation, only one athlete was disqualified from competition.ConclusionsIn elite athletes, integrating Holter monitoring into PPE improved the detection of intermittent arrhythmias that may be missed by a resting ECG alone, and providing complementary diagnostic information and representing a useful adjunct to echocardiography in comprehensive cardiovascular screening strategies, particularly in selected high-risk athletic populations. Future longitudinal studies are warranted to determine the clinical significance of these findings.

Anatomical and radiographic stroke topography predicts ventricular and atrial ectopic burden.

Cardiac complications are a significant cause of morbidity and mortality in patients with β-thalassemia major (TM). Early detection of subclinical cardiac involvement remains challenging, as conventional echocardiography and electrocardiography often fail to identify early dysfunction. Heart rate variability (HRV) reflects autonomic regulation of the heart and may serve as a sensitive marker for early cardiac impairment. To evaluate HRV in children with β-TM without clinical cardiac manifestations. A cross-sectional study was conducted on 40 children with β-TM and 40 age- and sex-matched healthy controls. All participants underwent full clinical assessment, laboratory investigations, and 24-hour ambulatory Holter monitoring. HRV parameters were analyzed in both time and frequency domains using Cardioscan CS12 software. Statistical comparisons between groups and correlations with hemoglobin and serum ferritin levels were performed using SPSS version 27. Children with β-TM showed significantly higher minimum and maximum heart rates and markedly lower HRV indices, including standard deviation of all normal-to-normal intervals (SDNN), standard deviation of the 5-minutes average normal-to-normal intervals, SDNN index, root mean square of successive differences, and percentage of normal-to-normal intervals differing by > 50 ms, compared with controls (P < 0.001). High-frequency (HF) power was significantly decreased, whereas the low-frequency/HF ratio was elevated (P < 0.001), indicating sympathetic predominance. Arrhythmias were recorded in 47.5% of patients, though HRV parameters did not differ significantly between those with and without arrhythmia. No correlation was found between HRV indices and hemoglobin or serum ferritin levels. Children with β-TM demonstrate significant autonomic imbalance, reflecting early cardiac involvement even before the onset of clinical symptoms. Routine HRV assessment could provide a valuable, non-invasive tool for early detection and risk stratification in pediatric thalassemia management.

ABSTRACTBackgroundVariants in MYO6 are well known causes of hereditary deafness and have occasionally been linked to cardiac abnormalities, including hypertrophic cardiomyopathy and prolonged QT interval. However, supraventricular tachycardia (SVT) has not previously been associated with this gene.AimTo describe a neonate with congenital deafness, paroxysmal SVT, and QT prolongation carrying a novel homozygous MYO6 variant.MethodsA 2‐month‐old male infant with bilateral congenital sensorineural hearing loss presented with recurrent paroxysmal SVT. Clinical evaluation included ECG, Holter monitoring, echocardiography, and laboratory studies. Whole‐exome sequencing followed by Sanger validation was performed to identify genetic alterations.ResultsThe infant experienced repeated SVT episodes responsive to adenosine and was noted to have a prolonged QTc interval of 569 ms in sinus rhythm. Echocardiography showed mild LV enlargement with preserved function and no structural anomalies. Genetic testing revealed a novel homozygous frameshift variant in MYO6 (c.2496_2497delAC; p.H833Qfs*5).ConclusionWhile causality cannot be confirmed, this observation raises the possibility that MYO6 dysfunction may contribute to arrhythmogenic susceptibility in addition to its established role in auditory function. Further studies are warranted to clarify the relationship between MYO6 variants and cardiac conduction abnormalities.