IntroductionAtrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with catheter ablation increasingly recommended as first-line therapy. Despite its effectiveness, 15% to 20% of patients require reassessment within the first month post-procedure. Standard follow-up relies on scheduled consultations and intermittent monitoring, which may delay recognition of recurrence or complications. Remote patient monitoring through conversational agents may address these gaps, yet evidence on feasibility and implementation in post-ablation care remains limited. This study aims primarily to evaluate the feasibility, usability, and acceptability of PROMBot-HSM-AF (Chatbot Platform to Collect Patient-reported Outcomes After AF Ablation, Santa Marta Hospital) during the first 3 months following AF catheter ablation.Methods and analysisPROMBot-HSM-AF is a single-center, open-label, randomized controlled pilot (feasibility) trial with two parallel groups, conducted at Santa Marta Hospital, Lisbon, Portugal. Seventy-six patients undergoing AF ablation will be randomized in a 1:1 ratio to either chatbot-supported follow-up or standard care. The primary feasibility parameters are: recruitment rate (proportion of eligible patients consenting), retention rate at 3 months, and chatbot engagement rate (proportion of chatbot prompts answered). Acceptability and usability will be assessed using behavioral indicators (engagement and retention), the System Usability Scale (SUS), the Post-Study System Usability Questionnaire (PSSUQ), and semi-structured interviews with patients and healthcare professionals. Quantitative data will be analyzed descriptively with exploratory between-group comparisons. Semi-structured interviews with patients and healthcare professionals will be analyzed using thematic content analysis.ConclusionsThis pilot trial will provide preliminary evidence on the feasibility and acceptability of integrating a chatbot-based platform into routine post-ablation care. Findings will inform refinement of the intervention and future effectiveness research in this population. The study addresses a critical gap in remote patient monitoring for post-procedural care.Clinical Trial Registrationhttps://clinicaltrials.gov/study/NCT07237178, identifier NCT07237178.

Syncope is a common cause of emergency department visits and is associated with heterogeneous clinical practice and substantial hospital resource use. We primarily aimed to quantify the direct per-patient hospital costs of syncope. Secondary aims were to characterize patterns of resource utilization, determine the cost structure by care pathway and functional component, and identify determinants of total per-patient cost. Additionally, we estimated the potential emergency department cost savings resulting from adherence to the 2018 European Society of Cardiology syncope guidelines. We conducted an observational, retrospective cohort study at a private hospital in Lisbon, Portugal, from 1 January to 31 December 2023, including pediatric (< 18 years) and adult (≥ 18 years) patients with a principal emergency department diagnosis of syncope (ICD-9-CM 780.2/992.1). Direct costs were assessed by micro-costing (bottom-up approach) from the hospital perspective (base year 2023), with patient-level analysis. Total per-patient cost was modeled using a generalized linear model as a function of age, sex, etiology, and total number of comorbidities as predictors. Potential emergency department savings were estimated using a counterfactual simulation of guideline-concordant diagnostic testing. We analyzed 375 patients (mean age 49.4 ± 26.5 years; 60.3

Abstract Introduction Catheter ablation for pulmonary vein isolation (PVI) is an established treatment for atrial fibrillation (AF). Different energy sources—thermal such as cryoablation (CRYO) and radiofrequency (RF), and non-thermal such as pulsed field ablation (PFA)—may have distinct impacts on the cardiac autonomic nervous system (ANS), a factor with potential prognostic implications. This study aimed to compare the effects of PFA, CRYO, and RF on autonomic function and its temporal evolution. Methods We conducted a prospective observational study in 89 patients with predominantly paroxysmal AF undergoing PVI with either pulsed field ablation (PFA; n=11), cryoablation (CRYO; n=45), or radiofrequency (RF; n=33). The combined cohort had a mean age of 59 ± 10 years and was predominantly male (64%). Autonomic function was assessed through heart rate variability (HRV) analysis in time and frequency domains during a tilt table test protocol. Assessments were performed at baseline (pre-ablation) and at 1, 3, and 6 months of follow-up. Results The PFA group demonstrated minimal changes in HRV parameters (ΔHR, ΔSDNN, ΔRMSSD ≈ 0), suggesting preservation of autonomic function. In contrast, groups undergoing thermal ablation (CRYO and RF) showed a significant increase in heart rate and a marked reduction in global HRV indices (SDNN) and parasympathetic markers (RMSSD, PHF) (p<0.01), indicating substantial autonomic denervation. Longitudinal analysis revealed partial recovery of chronotropic response and a progressive increase in low-frequency power at 3 and 6 months in the thermal ablation groups, suggestive of adaptive autonomic remodelling and reinnervation over time. Conclusion Pulsed field ablation demonstrates a superior autonomic safety profile, preserving intrinsic cardiac function compared to thermal energy sources (CRYO and RF), which induce significant denervation. The distinct temporal evolution of autonomic modulation amongst technologies underscores the importance of long-term monitoring and may have implications for ablation strategy selection and arrhythmia recurrence risk stratification.For image description, please refer to the figure legend and surrounding text.

Background and Objective: This systematic review evaluates the current state of Machine Learning (ML) methods for predicting Atrial Fibrillation (AF) recurrence following catheter ablation. With the growing use of ML, a systematic evaluation of performance and key influencing factors such as study design, data types, and reporting is needed. The main objectives are to provide an updated overview of current achievements of ML in this field, anticipate future challenges and opportunities, and derive methodological recommendations based on the findings. Methods: Seven databases were systematically searched, and studies proposing ML algorithms with well-documented implementation, testing, and reporting of performance metrics underwent a qualitative synthesis and risk-of-bias assessment. A meta-analysis of 17 studies was conducted using the Area Under the receiver operating characteristic Curve (AUC) as the most commonly reported performance metric. Results: The mean overall AUC was 0.81, indicating reasonable predictive accuracy, although there was substantial inter-study heterogeneity. Meta-regression identified sample size and input data type (clinical, imaging, or electrophysiological) as significant contributors to this heterogeneity. Subgroup analysis demonstrated that models incorporating complex data modalities achieved higher predictive accuracy and lower heterogeneity compared to those relying solely on simpler clinical variables. Conclusion: This review quantifies the performance of ML algorithms in predicting AF recurrence and establishes a benchmark for future research. It also highlights key challenges, including the lack of standardized datasets and limited generalizability. Incorporating more complex data sources may improve model performance, reduce inconsistencies, and enhance the potential clinical applicability of ML models in guiding patient management.

Catheter ablation is the definitive treatment for Wolff-Parkinson-White (WPW) syndrome, where precise preprocedural localisation of accessory pathways (APs) is critical to optimise outcomes and reduce procedural time. Traditional imaging and ECG techniques often fall short, particularly for septal APs. This study evaluated the diagnostic accuracy of an imageless electrocardiographic imaging (ECGi) system that does not require additional CT or MRI in localising APs for targeted ablation. In this single-centre prospective study, adult and paediatric patients with WPW syndrome referred for AP ablation were consecutively enrolled. Non-invasive electroanatomic mapping was conducted using an imageless ECGi system, which uses a 128-electrode array to record body-surface potentials, a 3D torso model generated via a structured light camera, and an artificial intelligence algorithm to estimate the patient’s biventricular geometry. Epicardial electrograms were computed to obtain epicardial ventricular activation maps. The atrioventricular junction was divided into 11 regions using a modified Pappone classification to support AP localisation, with only the pathway responsible for ventricular pre-excitation being analysed in patients with multiple APs. The differential diagnostic capacity of the 12-lead ECG and ECGi was assessed by comparing the predicted AP locations with the ablation sites in invasive electroanatomical mapping (EAM) across three endpoints: (1) localisation within the same region, (2) within the same or adjacent regions, and (3) correct laterality (right, left, or septal). The study included 14 adult patients (mean age: 34.4 ± 16.4 years, 71.4% male) and six paediatric patients (mean age: 14.3 ± 0.71 years, 100% male). AP distribution included eleven septal pathways, eight left-sided pathways, and 1 Mahaim fibre. ECGi achieved a global accuracy rate of 80.0% in precisely localising APs to the correctly predefined AV region. When allowing for localisation in the adjacent area, the accuracy improved to 95.0%, and the accuracy in identifying laterality (right, left, or septal) was 90.0%. Notably, all mislocalizations were confined to septal pathways, suggesting the potential limitations of the current ECGi configuration in these complex anatomical regions. ECGi’s diagnostic capacity was significantly superior to the 12-lead ECG (p<0.05), which achieved an average accuracy of 45% for precise AP localisation, 70% when including the adjacent region, and 72.5% for laterality. ECGi demonstrates a higher accuracy than the 12-lead ECG for AP localisation in WPW syndrome, supporting its use as a diagnostic tool for pre-ablation planning. Future integration of endocardial and epicardial mapping could improve accuracy for septal APs, further enhancing targeted ablation.

Genetics has assumed a pivotal role in clarifying the pathophysiology of cardiomyopathies, facilitating molecular diagnosis, and enabling effective family screening. The advent of next-generation sequencing has revolutionized genetic testing by enabling cost-effective, high-throughput analysis. It is imperative for cardiovascular physicians to mainstream genetic testing into their clinical decision-making. Although a definitive genotype-phenotype correlation may not always be evident, several genotypes have emerged as valuable risk predictors for disease severity and progression. European guidelines emphasize the importance of genetic tests for predicting clinical outcome in cardiomyopathies. While further research is essential to bridge existing gaps in the genetic evidence on cardiomyopathies, there is considerable potential for significant advancements.

It is unknown whether type 2 diabetes mellitus (T2DM) influences the vascular function response to aerobic exercise. We examined brachial artery flow-mediated dilation (FMD) and flow-mediated slowing (FMS) of pulse wave velocity (PWV), 10-and 60-min after a high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) in adults with and without T2DM. Twelve older male adults with T2DM (57-84 years), and twenty-four healthy young and older adults (12 per group, aged 20-40 years and 57-76 years, respectively), completed an acute bout of HIIE, MICE, and a non-exercise condition. FMD was evaluated by the same researcher following standardized guidelines. FMS was calculated from the manufacturer's PWV beta formulas. Central arterial stiffness was estimated via carotid-femoral PWV (cfPWV). %FMD was reduced (d= - 5.94%, 95% CI: - 10.50 to - 1.38%, p = 0.002), whereas %FMS increased (d = 4.55%, 95% CI: 0.62 to 8.48%, p = 0.01), 10-min after HIIE only in adults with T2DM, normalizing 60-min into recovery. Conversely, %FMD was increased (d = 5.33%, 95% CI: 0.76 to 9.89%, p = 0.009) 10-min after MICE only in adults with T2DM. cfPWV remained unchanged following HIIE and MICE in all groups. We report disease-associated vascular function responses to aerobic exercise suggesting both HIIE and MICE uncover transient vascular alterations in older adults with T2DM.

Introduction: Vasovagal syncope is a prevalent condition marked by transient loss of consciousness due to abrupt decreases in systemic blood pressure and/or heart rate. Despite its clinical impact, the underlying haemodynamic mechanisms remain poorly defined, and data on age-related differences are limited and sometimes contradictory. Objectives: This study aimed to characterise haemodynamic adaptation patterns during a head-up tilt (HUT) test in adult (≥18 years) and paediatric (<18 years) patients with recurrent reflex syncope, compared with healthy adult controls. We sought to identify distinct temporal haemodynamic signatures and clarify potential age-related differences in syncope mechanisms. Methods: In this prospective observational study, participants underwent continuous beat-to-beat monitoring of cardiac output (CO), stroke volume (SV), heart rate (HR), and total peripheral resistance (TPR) during HUT. Linear mixed-effects models were used to examine time-by-group interactions, and post-hoc analyses were adjusted for multiple comparisons. Effect sizes and confidence intervals (CIs) were reported to quantify the magnitude of differences. Results: A total of 187 fainters (paediatric n = 81, adult n = 106) and 108 non-fainters (including 30 healthy controls) were studied. Compared to adult fainters, paediatric fainters showed a 24% larger decline in CO from baseline (mean difference of 1.1 L/min [95% CI: 0.5–1.7], p = 0.003) and a 15–20 bpm higher peak HR (p = 0.001) during presyncope. Both subgroups experienced significant drops in TPR, which were more pronounced in paediatric fainters (effect size = 0.27, 95% CI: 0.12–0.42). Non-fainters (including controls) maintained relatively stable haemodynamics, with no significant decrease in CO or TPR (p > 0.05). Age-related comparisons indicated a heavier reliance on HR modulation in paediatric fainters, leading to an earlier transition from compensated to pre-syncopal states. Conclusions: These findings demonstrate that paediatric fainters exhibit more abrupt decreases in CO and TPR than adults, alongside higher HR responses during orthostatic stress. Targeted interventions that address this heightened chronotropic dependency—such as tilt-training protocols or strategies to improve venous return—may be particularly beneficial in younger patients. An age-specific approach to diagnosis and management could improve risk stratification, minimise recurrent episodes, and enhance patient outcomes.

We examined the inter-day repeatability of cardiovagal baroreflex sensitivity (BRS) and heart rate variability (HRV) metrics during a dual-intensity cycling protocol in healthy young males and females. Forty young adults (20 males, 20 females; age: 18–31 years) completed two randomized reclined cycling bouts at a moderate (50

BackgroundArterial stiffness and cardiac autonomic function are crucial indicators of cardiovascular health. Acute exercise and age impact these parameters, but research often focuses on specific exercise activities, lacking ecological validity.MethodsWe examined the acute effects of commercially available group fitness classes (indoor cycling, resistance training, combined exercise) on arterial stiffness and vagal-related heart rate variability (HRV) indices in twelve young and twelve middle-aged adults. Participants attended four sessions, including exercise and control conditions, with measurements taken at rest and during recovery.ResultsMiddle-aged, but not young adults, showed reductions in central and peripheral systolic blood pressure 20-min into recovery across all exercise modalities (range: -7 to -8 mmHg p < 0.05). However, arterial stiffness remained unchanged. Similarly, vagal-related HRV indices (range: -0.51 to -0.90 ms, p < 0.05) and BRS (-4.03, p < 0.05) were reduced immediately after exercise, with differences persisting 30 min into recovery only after indoor cycling. Resistance and combined exercise elicited similar cardiovagal modulation and delayed baroreflex sensitivity recovery to cycling exercise, despite higher energy expenditure during indoor cycling (+87 to +129 kcal, p < 0.05).ConclusionAcute group fitness classes induce age-dependent alterations in blood pressure, but not in arterial stiffness or cardiovagal modulation. While the overall cardiovascular effects were generally consistent, differences in autonomic recovery were observed between exercise modes, with prolonged effects seen after indoor cycling. This suggests that exercise prescription should consider both age and exercise modality, as well as recovery time. The findings also emphasize the importance of ecological validity in exercise interventions, highlighting that acute effects on cardiovascular health in real-world settings may differ from those observed in controlled laboratory environments (ID: NCT06616428).

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia, presenting a significant global healthcare challenge due to its rising incidence, association with increased morbidity and mortality, and economic burden. This arrhythmia is driven by a complex interplay of electrical, structural, and autonomic remodelling, compounded by genetic predisposition, systemic inflammation, and oxidative stress. Despite advances in understanding its pathophysiology, AF management remains suboptimal, with ongoing debates surrounding rhythm control, rate control, and anticoagulation strategies. Animal models have been instrumental in elucidating AF mechanisms, facilitating preclinical research, and advancing therapeutic development. This review critically evaluates the role of animal models in studying AF, emphasizing their utility in exploring electrical, structural, and autonomic remodelling. It highlights the strengths and limitations of various models, from rodents to large animals, in replicating human AF pathophysiology and advancing translational research. Emerging approaches, including optogenetics, advanced imaging, computational modelling, and tissue engineering, are reshaping AF research, bridging the gap between preclinical and clinical applications. We also briefly discuss ethical considerations, the translational challenges of animal studies and future directions, including integrative multi-species approaches, omics technologies and personalized computational models. By addressing these challenges and addressing emerging methodologies, this review underscores the importance of refining experimental models and integrating innovative technologies to improve AF management and outcomes.

Cardiomyopathies may present as a manifestation of various inherited syndromes. Recognizing the rarity and diagnostic challenges of syndromic and metabolic cardiomyopathies is crucial, as their identification holds significant implications for targeted treatment and enables the use of specific risk stratification tools. Genetics has assumed a pivotal role in clarifying the pathophysiology of cardiomyopathies, facilitating molecular diagnosis, and enabling effective family screening. The advent of next-generation sequencing has revolutionized genetic testing, enabling cost-effective, high-throughput analyses, facilitating the diagnosis of these rare conditions, and allowing the provision of specific management and therapeutics.

Background and Objectives: Despite advances in the surgical management of patients with Fontan circulation, their exercise capacity and quality of life remain significantly impaired. Exercise-based cardiac rehabilitation (CR) offers promising improvements in these areas, but the implementation and adherence to these programmes are often inconsistent. This systematic review and meta-analysis aimed to evaluate the safety, efficacy, and optimal exercise modalities for Fontan patients. Materials and Methods: A systematic search of PubMed, Scopus, Web of Science, and Cochrane Library was conducted on 24 August 2023. Studies were screened and assessed for quality using the Cochrane RoB Tool 2 and STROBE checklist. Meta-analysis was performed using a continuous random-effects model to determine the effectiveness of various CR interventions, including aerobic exercise training (AET), resistance training, and inspiratory muscle training (IMT). Results: A total of 26 studies (7 RCTs, 19 cohorts) comprising 22 distinct cohorts were included, with a total sample size of 428 Fontan patients. The interventions ranged from 4 weeks to 24 months and included AET (18 studies), resistance training (11 studies), and IMT (6 studies). The meta-analysis revealed significant improvements in exercise capacity, with a pooled mean difference in peak VO2 of 1.947 (95% CI: 1.491 to 2.402, p < 0.001). Subgroup analyses showed that combined AET and resistance training had the most robust effect, with a mean difference of 2.11 (95% CI: 1.57 to 2.65, p < 0.001). Home-based interventions showed significant benefits, while supervised and hybrid interventions did not show statistically significant differences. Publication bias was identified, particularly in home-based interventions, where smaller studies demonstrated larger effect sizes, as confirmed by Egger’s test (Intercept = 2.417, 95% CI: 1.498 to 3.337, p = 0.001). However, no significant bias was detected in supervised or hybrid interventions, which displayed symmetrical distributions in funnel plots and non-significant Egger’s test results. Conclusions: CR appears to be an effective intervention for improving exercise capacity in Fontan patients, particularly when combining AET with resistance training. Home-based programmes offer promising results, though the potential for publication bias, especially in smaller studies, warrants cautious interpretation of these findings. Further research is needed to refine protocols, explore long-term outcomes, and determine the underlying mechanisms, particularly for patients with more severe clinical presentations. The low incidence of adverse events across the studies reinforces the safety of these interventions.

Background and Objectives: The Fontan procedure, a palliative surgery for univentricular heart physiology, often reduces exercise capacity and quality of life. This study aimed to evaluate the impact of cardiac rehabilitation (CR) on improving outcomes in Fontan patients to inform evidence-based care. Materials and Methods: Fontan patients aged 8–30 participated in a structured CR program for at least three months. The program included weekly aerobic and resistance training sessions with educational and nutritional guidance. Baseline and post-CR assessments included cardiac function, fitness, daily activity, and health-related quality of life (HRQOL). Results: The cohort included ten Fontan patients, of whom six had a right systemic ventricle. CR significantly improved cardiorespiratory fitness, as seen in VO2 max (from 27.92 ± 5.15 to 34.69 ± 1.14 mL/kg/min, p = 0.0089) and percent predicted VO2 (from 0.67 ± 0.18 to 0.90 ± 0.02, p = 0.005). VCO2 increased by +8.68 ± 8.59 mL/kg/min but did not reach statistical significance (p = 0.05). Most haemodynamic and ventilatory parameters showed no significant improvement. All the SF-36 questionnaire domains showed significant HRQOL gains (p < 0.001). High adherence (85–93%), no adverse events, and reduced NT-proBNP levels supported the program’s safety. Conclusions: This study’s findings have important implications for the care of Fontan patients. CR significantly improved exercise capacity and HRQOL in Fontan patients across various anatomies, particularly in the right systemic ventricle. Integrating physical conditioning into standard care could reduce long-term morbidity and mortality; however, further research is needed to refine the protocols and confirm sustained benefits.

Introduction In patients with atrial fibrillation (AF), up to one third have recurrence after a first catheter ablation (CA). Epicardial adipose tissue (EAT) has been considered to be closely related to AF, with a potential role in its recurrence. We aimed to evaluate the association between the volume of EAT measured by cardiac computed tomography (CT) and AF recurrence after CA. Methods Consecutive AF patients underwent a standardized cardiac CT protocol for quantification of EAT, thoracic adipose volume (TAV) and left atrium (LA) volume before CA. An appropriate cut-off of EAT was determined and risk recurrence was estimated. Results 305 patients (63.6 % male, mean age 57.5 years, 28.2 % persistent AF) were followed for 24 months; 23 % had AF recurrence at 2-year mark, which was associated with higher EAT (p = 0.037) and LAV (p < 0.001). Persistent AF was associated with higher EAT volumes (p = 0.010), TAV (p = 0.003) and LA volumes (p < 0.001). EAT was predictive of AF recurrence (p = 0.044). After determining a cut-off of 92 cm3, survival analysis revealed that EAT volumes > 92 cm3 showed higher recurrence rates at earlier time points after the index ablation procedure (p = 0.006), with a HR of 1.95 (p = 0.008) of AF recurrence at 2-year. After multivariate adjustment, EAT > 92 cm3 remained predictive of AF recurrence (p = 0.028). Conclusion The volume of EAT measured by cardiac CT can predict recurrence of AF after ablation, with a volume above 92 cm3 yielding almost twice the risk of arrhythmia recurrence in the first two years following CA. Higher EAT and TAV are also associated with persistent AF.

Background: Catheter ablation (CA) is a well-established treatment for atrial fibrillation (AF). However, its effects on autonomic function and underlying mechanisms remain poorly understood. This study investigated autonomic and haemodynamic changes following CA and explored their potential implications for patient outcomes. Methods: Seventy-eight patients with AF underwent CA and were followed up at one, three, and six months. Autonomic function was assessed using a combination of head-up tilt (HUT), handgrip (HG), and deep breathing (DB) manoeuvres along with baroreflex sensitivity (BRS) and baroreflex effectiveness index (BEI) evaluation. Heart rate (HR), blood pressure (BP), and their variability were measured at each time point. Results: Significant autonomic alterations were observed after ablation, particularly at one month, with reductions in parasympathetic tone and baroreflex function. These changes gradually normalised by six months. Both pulmonary vein isolation (PVI) and cryoablation (CryO) had similar effects on autonomic regulation. Improvements in quality of life, measured by the AFEQT scores, were consistent with these physiological changes. Conclusions: CA for AF induces significant time-dependent autonomic and haemodynamic changes with recovery over six months. These findings underscore the need for ongoing monitoring and personalised post-ablation management. Further research is required to explore the mechanisms driving these alterations and their long-term impacts on patient outcomes.