Post-acute exercise cardiovagal modulation in older male adults with and without type 2 diabetes.

PURPOSE: We examined heart rate variability (HRV) and baroreflex sensitivity (BRS) disease- and age-related response at 10-and 60-min after an acute high-intensity interval (HIIE) and moderate continuous exercise (MICE) in older adults with and without type 2 diabetes mellitus (T2DM) and healthy young adults. METHODS: Twelve older male adults with (57-84 years) and without T2DM (57-76 years) and 12 healthy young male adults (20-40 years) completed an isocaloric acute bout of HIIE, MICE, and a non-exercise condition in a randomized order. Time and Wavelets-derived frequency domain indices of HRV and BRS were obtained in a supine position and offline over 2-min time-bins using Matlab. RESULTS: HIIE but not MICE reduced natural logarithm root mean square of successive differences (Ln-RMSSD) (d = - 0.85; 95% CI - 1.15 to - 0.55 ms, p < 0.001), Ln-high-frequency power (d = - 1.60; 95% CI - 2.24 to - 0.97 ms2; p < 0.001), and BRS (d = - 6.32; 95% CI - 9.35 to - 3.29 ms/mmHg, p < 0.001) in adults without T2DM (averaged over young and older adults without T2DM), returning to baseline 60 min into recovery. These indices remained unchanged in older adults with T2DM after HIIE and MICE. Older adults with T2DM had lower resting Ln-RMSSD and BRS than aged-matched controls (Ln-RMSSD, d = - 0.71, 95% CI - 1.16 to - 0.262 ms, p = 0.001; BRS d = - 3.83 ms/mmHg), 95% CI - 6.90 to - 0.76, p = 0.01). CONCLUSIONS: Cardiovagal modulation following acute aerobic exercise is intensity-dependent only in adults without T2DM, and appears age-independent. These findings provide evidence of cardiac autonomic impairments in older adults with T2DM at rest and following aerobic exercise.

The Effect of Cardiac Rehabilitation in Paediatric Fontan Circulation Patients: A Prospective Intervention Study.

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.

Prevalence, Management, and Outcomes of Atrial Fibrillation in Paediatric Patients: Insights from a Tertiary Cardiology Centre.

Background and Objectives: Atrial fibrillation (AF) is increasingly recognised in paediatric patients, presenting unique challenges in management due to its association with various underlying heart conditions. This study aimed to evaluate the prevalence, management strategies, and outcomes of AF in this population. Materials and Methods: A retrospective analysis was conducted at a tertiary paediatric cardiology centre, including patients aged ≤18 years diagnosed with AF between January 2015 and December 2023. The study focused on demographic details, clinical presentations, treatments, and outcomes. Descriptive statistics were employed to assess treatment efficacy, recurrence rates, and complications. Results: The study included 36 paediatric patients (median age: 15 years, IQR: 13-17; 58% male). Of these, 52.8% had acquired heart disease, 16.7% had congenital heart anomalies, and 16.7% presented with lone AF. The initial management strategies involved electrical cardioversion in 53.3% of patients and pharmacological conversion with amiodarone in 46.7%. Rhythm control therapy was administered to over 80% of the cohort, and 63.9% were placed on oral anticoagulation, predominantly for rheumatic and congenital heart diseases. The overall success rate of rhythm control was 96.2%, with an AF recurrence rate of 3.8%. Ischemic stroke was the most common complication, occurring in three patients, all with underlying rheumatic heart disease. Conclusions: AF in paediatric patients is predominantly associated with rheumatic and congenital heart diseases, though a significant proportion of patients present with lone AF. Despite effective rhythm control in most cases, neurological complications, particularly ischemic strokes in patients with underlying heart disease, remain a critical concern. These findings underscore the need for more comprehensive studies to better understand the aetiology, risk factors, and optimal management strategies for paediatric AF.

Cardiovagal Modulation in Young and Older Male Adults Following Acute Aerobic Exercise.

We compared response patterns of cardiovagal modulation through heart-rate variability (HRV) and baroreflex sensitivity (BRS) indices at 10 and 60 min after an acute bout of high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) in active young and older adults. Twelve young (aged 20-40 years) and older (aged 57-76 years) healthy and active male adults performed an isocaloric acute bout of HIIE, MICE, or a non-exercise condition in a randomized order. HRV and BRS indices were analyzed offline with R-R intervals obtained from a supine position. HIIE decreased natural logarithm (Ln) standard deviation of NN intervals (d=-0.53; 95% CI: -0.77 to -0.30 ms, p<0.001), Ln-root mean square of successive differences (d=-0.85; 95% CI: -1.09 to -0.61 ms, p<0.001), Ln-high-frequency power (d=-1.60; 95% CI: -2.11 to -1.10 ms2; p<0.001), and BRS (d=-6.28; 95% CI: -8.91 to -3.64 ms/mmHg, p<0.001) after exercise in young and older adults, whereas MICE did not. Indices returned to baseline after 60 min. We found no evidence of age-associated response patterns in HRV or BRS to a single bout HIIE or MICE in active participants. HIIE reduced cardiovagal modulation in active young and older adults, returning to baseline values 60 min into recovery.

Hypothalamic Ion Channels in Hypertension.

Hypertension is a prevalent and major health problem, involving a complex integration of different organ systems, including the central nervous system (CNS). The CNS and the hypothalamus in particular are intricately involved in the pathogenesis of hypertension. In fact, evidence supports altered hypothalamic neuronal activity as a major factor contributing to increased sympathetic drive and increased blood pressure. Several mechanisms have been proposed to contribute to hypothalamic-driven sympathetic activity, including altered ion channel function. Ion channels are critical regulators of neuronal excitability and synaptic function in the brain and, thus, important for blood pressure homeostasis regulation. These include sodium channels, voltage-gated calcium channels, and potassium channels being some of them already identified in hypothalamic neurons. This brief review summarizes the hypothalamic ion channels that may be involved in hypertension, highlighting recent findings that suggest that hypothalamic ion channel modulation can affect the central control of blood pressure and, therefore, suggesting future development of interventional strategies designed to treat hypertension.

Vascular function long term after Kawasaki disease: another piece of the puzzle?

BACKGROUND: Kawasaki disease is an acute systemic vasculitis. Cardiac complications are frequent and include endothelial dysfunction in patients with coronary anomalies. Thus far, endothelial dysfunction in patients with no coronary lesions is poorly understood. Our aim was to access the vascular function in adolescents and young adults long term after Kawasaki disease, but without coronary aneurysms or any other cardiac risk factors. METHODS: We carried out a single-centre prospective study in a Portuguese population. We evaluated two groups of subjects: (1) Kawasaki disease patients over 11 years of age, diagnosed >5 years ago, with no coronary lesions or any other risk factors for cardiovascular disease; (2) control group of individuals without cardiovascular risk factors. Patients and controls were clinically assessed. Endo-PAT and carotid intima-media thickness assessment were performed to determine vascular function. RESULTS: In total, 43 Kawasaki disease patients were assessed and compared with 43 controls. Kawasaki disease patients presented a decreased reactive hyperaemia index compared with controls (1.59±0.45 versus 1.98±0.41; p<0.001). Augmentation index was similar in both groups (-4.5±7 versus -5±9%; p 0.6). The mean carotid intima-media thickness was not significantly increased in the Kawasaki disease group. There were no statistically significant changes with regard to laboratory data. CONCLUSIONS: Children with Kawasaki disease may have long-term sequelae, even when there is no discernible coronary artery involvement in the acute stage of the disease. Further research is needed to assess whether known strategies to improve endothelial function would bring potential benefits to Kawasaki disease patients.

Bridging thoracic endovascular aneurysm repair for a late rupture following aortic coarctation angioplasty.

UNLABELLED: Introduction Thoracic endovascular aneurysm repair has been employed to treat late complications after aortic coarctation correction. However, its use in children has seldomly been reported. Case report We present the case of a 15-year-old child who presented with a ruptured aneurysm of the descending aorta complicated later by an aortic-oesophageal fistula following aortic coarctation stenting that was managed with multiple bridging endovascular interventions until a definitive repair was performed. CONCLUSION: Thoracic endovascular aneurysm repair may be used successfully as a bridging intervention to a definitive repair in children with life-threatening aortic complications following aortic coarctation repair.

Successful catheter ablation of a left anterior accessory pathway from the non-coronary cusp of the aortic valve.

Left anterior accessory pathways are considered to be rare findings. Catheter ablation of accessory pathways in this location remains a challenging target, and few reports about successful ablation of these accessory pathways are available. We describe our experience regarding a case of a manifest left anterior accessory pathway ablation using radiofrequency energy at the junction of the left coronary cusp with the non-coronary cusp.

An insight into the autonomic and haemodynamic mechanisms underlying reflex syncope in children and adolescents: a multiparametric analysis.

Around 15% of children and adolescents experience at least one episode of syncope until adulthood. Excluding cardiac disease, the majority of syncopes are of reflex origin and benign in nature. In this situation, a tilt test is conducted to reproduce symptoms and to evaluate cardiovascular adaptations to orthostatism, but its mechanisms are not yet well defined. Here, we investigated haemodynamics and autonomic activity during tilt in young patients. Patients (n=113) with unexplained syncope were enrolled. Tilt followed a standard protocol without provocative agents. A positive response (fainters) was defined as a sudden development of syncope or presyncope associated with hypotension, bradycardia, or both. Haemodynamic parameters, autonomic activity, and baroreflex sensibility were evaluated. Data were analysed on baseline; immediately after tilting; on tilt adaptation; before fainting or before tilt-down for non-fainters; and on tilt-down. A total of 45 patients experienced syncope after a mean time of 18 minutes. During tilting up, fainters showed lower blood pressure and peripheral resistance values, which decreased progressively with time together with baroreflex sensibility. Sympathetic tone increased massively along time till syncope. No changes in cardiac output and heart rate were observed. Results show a strong effort of the autonomic nervous system to adapt to orthostatic stress through different magnitudes of sympathetic output, which was maximal before syncope without apparent modifications of parasympathetic tone. These changes suggest an imbalance between both branches of the autonomic nervous system, not enabling a time-progressive adaptation and leading the subject to faint.

Linking Sleep Disorders to Atrial Fibrillation: Pathways, Risks, and Treatment Implications.

Sleep is a complex biobehavioural process essential for overall health, with various dimensions including duration, continuity, timing, and satisfaction. This study investigated the intricate relationships between common sleep disorders such as insomnia and obstructive sleep apnoea (OSA) and their impact on atrial fibrillation (AF), a prevalent arrhythmia with significant health implications. Using a comprehensive review of the current literature, this study examined the pathophysiological mechanisms linking sleep disorders to cardiovascular risks, focusing on autonomic nervous system disturbances, inflammation, and oxidative stress associated with OSA. These findings indicate that sleep disorders significantly elevate the risk of AF through mechanisms such as increased sympathetic activity and structural cardiac remodelling. Additionally, this study highlights the potential benefits of treating sleep disorders, particularly with continuous positive airway pressure (CPAP) therapy, in reducing AF recurrence and improving cardiovascular outcomes. This conclusion emphasises the importance of integrated therapeutic approaches that address both sleep disorders and AF to enhance patient outcomes and quality of life. Future research should explore these connections to develop more effective and holistic treatment strategies.

AFTER-CA: Autonomic Function Transformation and Evaluation Following Catheter Ablation in Atrial Fibrillation.

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.

Left Atrial Wall Thickness Estimated by Cardiac CT: Implications for Catheter Ablation of Atrial Fibrillation.

Atrial wall thickness (AWT) is a significant factor in understanding the pathological physiological substrate of atrial fibrillation, with a potentially substantial impact on the outcomes of catheter ablation procedures. Precise measurements of the AWT may provide valuable insights for categorising patients with AF and planning targeted interventions. Objectives: The purpose of this study was to evaluate the characteristics of the left atrium (LA) using non-invasive multidetector computed tomography (MDCT) scans and subsequent three-dimensional (3D) image post-processing using novel software designed to calculate atrial thickness dimensions and mass. Methods: We retrospectively analysed 128 consecutive patients (33.6% females; mean age 55.6 ± 11.2 years) referred for AF ablation (37 with persistent AF and 91 with paroxysmal AF) who underwent preprocedural MDCT. The images were post-processed and analysed using the ADAS software (Galgo Medical), automatically calculating the LA volume and regional wall thickness. In addition, the software employed a regional semi-automatic LA parcellation feature that divided the atrial wall into 12 segments, generating atrial wall thickness (AWT) maps per segment for each patient. Results: This study demonstrated considerable variability in the average thickness of LA walls, with the anterior segments being the thickest across the cohort. Distinct sex-specific differences were observed, with males exhibiting greater anterior and septal wall thickness than females. No significant associations were identified between the average AWT and body mass index, LA volume, or sphericity. Survival analysis conducted over 24 months revealed a meaningful relationship between mean anterior wall thickness and recurrence-free survival, with increased thickness associated with a lower likelihood of AF-free survival. No such relationship was observed for the indexed LA volume. Conclusions: The variability in AWT and its association with recurrence-free survival following AF ablation suggest that AWT should be considered when stratifying patients for AF management and ablation strategies. These findings underscore the need for personalised treatment approaches and further research on the interplay of the structural properties of the left atrium as factors that can serve as important prognostic markers in AF treatment.

Evaluation of left atrial strain imaging and integrated backscatter as predictors of recurrence in patients with paroxysmal, persistent, and long-standing persistent atrial fibrillation undergoing catheter ablation.

BACKGROUND: Impaired left atrial (LA) strain predicts atrial fibrillation (AF) recurrence after catheter ablation (CA), but currently there is no cut-off to guide patient selection for CA. Integrated backscatter (IBS) is a promising tool for noninvasive quantification of myocardial fibrosis. The aim of this study was to compare LA strain and IBS between paroxysmal, persistent, and long-standing persistent AF and evaluate their association with AF recurrence after CA. METHODS: Analysis of consecutive patients with symptomatic paroxysmal and persistent AF who underwent CA. LA phasic strain, strain rate and IBS were assessed by two-dimensional speckle-tracking at baseline. RESULTS: We analyzed 78 patients, 31% with persistent AF (46% long-standing AF), 65% male, mean age 59 ± 14 years, who underwent CA and were followed-up for 12 months. AF recurrence occurred in 22 (28%) patients. LA phasic strain parameters were significantly impaired in patients with AF recurrence and were independent predictors of AF recurrence in a multivariable analysis. LA reservoir strain (LASr) < 18% predicted AF recurrence with 86% sensitivity and 71% specificity, with a higher predictive power compared to LA volume index (LAVI). LASr < 22% in paroxysmal AF and LASr < 12% in persistent AF correlated with AF recurrence. Increased IBS was a predictor of AF recurrence in patients with paroxysmal AF. CONCLUSION: LA phasic strain parameters were predictors of AF recurrence after CA, independently of LAVI and AF subtype. LASr < 18% showed a higher predictive power compared to LAVI. Further studies are needed to investigate the role of IBS as a predictor of AF recurrence.

Epicardial adipose tissue volume assessed by cardiac CT as a predictor of atrial fibrillation recurrence following catheter ablation.

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.

Postictal generalized EEG suppression is not associated with periictal cardiac autonomic instability in people with convulsive seizures.

PURPOSE: Postictal generalized EEG suppression (PGES) seems to be a pathophysiologic hallmark in ictal recordings of sudden unexpected death in epilepsy (SUDEP). It has recently been suggested that presence and duration of PGES might be a predictor of SUDEP risk. Little is known about the etiology of PGES. METHODS: We conducted a retrospective case-control study in 50 people with convulsive seizures (CS) recorded on digital video-electroencephalography (EEG). One CS per individual was reviewed for presence and duration of PGES by two independent observers: Preictal and postictal heart rate (HR) (1 min before seizure onset and 1, 3, 5, 15, and 30 min after seizure end) and frequency domain measures of heart rate variability (HRV), including the ratio of low frequency (LF) versus high frequency (HF) power, were analyzed. The relationship between PGES and periictal autonomic changes was evaluated, as well as its association with several clinical variables. KEY FINDINGS: Thirty-seven individuals (74%) exhibited PGES and 13 (26%) did not. CS resulted in a significant increase of periictal HR and the LF/HF ratio. PGES was associated with neither periictal HR (mean HR difference between PGES+ and PGES- seizures: -2 beats per minute [bpm], 95% confidence interval [CI] -10 to +6 bpm) nor HRV change. There was no association between the duration of PGES and periictal HR change. People with PGES were more likely to be asleep before seizure onset (odds ratio [OR] 4.7, 95% CI 1.2-18.3) and had a higher age of onset of epilepsy (median age 15 vs. 4 years). SIGNIFICANCE: PGES was not associated with substantial changes in measures of cardiac autonomic instability but was more prevalent in CS arising from sleep.

Long-term evaluation of endothelial function in Kawasaki disease patients.

BACKGROUND: Kawasaki disease is an acute systemic vasculitis. Cardiac complications are frequent and include endothelial dysfunction in patients with coronary anomalies. So far, the presence of endothelial dysfunction in patients with no coronary lesions has not been demonstrated. Peripheral arterial tonometry (Endo-PAT) measures the microvascular function in response to local ischaemia and has been validated in adult population, but its use in children is scarce. Aim To evaluate endothelial dysfunction in children as a long-term complication after Kawasaki disease using Endo-PAT. METHODS: We evaluated two groups of subjects: (1) Kawasaki disease patients over 11 years of age, diagnosed for >5 years, with no coronary lesions, or any other risk factors for cardiovascular disease; (2) control group of individuals without cardiovascular risk factors. Patients and controls were clinically accessed. Endo-PAT was performed to determine reactive hyperaemia index and augmentation index. RESULTS: A total of 35 individuals (21 males, age 21 ± 6 years) were evaluated (group 1: 19; controls: 16). Kawasaki disease patients presented significant lower reactive hyperaemia index (1.68 ± 0.49 versus 2.31 ± 0.53; p = 0.001). Augmentation index was similar in both groups (-10 ± 7 versus -11 ± 5; p > 0.005). Most patients with Kawasaki disease disclosed endothelial dysfunction (68%) compared with only 12% in controls. CONCLUSIONS: Endo-PAT is feasible and reproducible in the child population. Endothelial dysfunction is a frequent long-term complication in patients after Kawasaki disease with normal appearing coronary arteries. However, these results need validation in a larger population.

Central Autonomic Network Regions and Hypertension: Unveiling Sympathetic Activation and Genetic Therapeutic Perspectives.

INTRODUCTION: Hypertension, a leading cause of death, was investigated in this study to understand the role of specific brain regions in regulating blood pressure. The lateral parabrachial nucleus (LPBN), Kolliker-fuse nucleus (KF), and periductal grey matter (PAG) were examined for their involvement in hypertension. METHODS: Lentiviral vectors were used to alter the activity of these brain regions in hypertensive rats. Over a 75-day period, blood pressure, heart rate, reflex responses, and heart rate variability were measured. RESULTS: Decreasing the activity in the LPBN resulted in a reduced sympathetic outflow, lowering the blood pressure and heart rate. In the KF, the sympathetic activity decreased and chemoreflex variation was attenuated, without affecting the blood pressure. Silencing the PAG had no significant impact on blood pressure or sympathetic tone, but decreased cardiac baroreflex gain. DISCUSSION: These findings highlight the significant role of the LPBN in hypertension-related sympathetic activation. Additionally, LPBN and KF neurons appear to activate mechanisms that control respiration and sympathetic outflow during chemoreceptor activation. CONCLUSIONS: The study provided insights into the contribution of the midbrain and pontine regions to neurogenic hypertension and offers potential avenues for future genetic interventions and developing novel treatment approaches.

The TANGO2 disease and the therapeutic challenge of acute arrhythmia management: a case report.

Background: TANGO2-related metabolic encephalopathy and arrhythmia are a rare, newly recognized, and likely under-diagnosed condition. First described in 2016, it is characterized by developmental delay and recurrent metabolic crisis. During these episodes, patients may present QTc prolongation and ventricular arrhythmias. Case summary: A 13-year-old female, with developmental delay, presented with severe rhabdomyolysis and an initially normal electrocardiogram (ECG). Due to the worsening of rhabdomyolysis, QTc prolongation was identified (QTc 570 ms) and oral ß-blocker therapy started. A non-sustained ventricular tachycardia developed, initially managed with magnesium and lidocaine. After a short period, an arrhythmic storm of polymorphic ventricular extrasystoles induced Torsade de Pointes (TdP) was triggered. A temporary percutaneous pacing lead was placed and esmolol infusion started. The electrical instability ran in parallel with the increasing severity of rhabdomyolysis and systolic ventricular function decline. Genetic testing identified a pathogenic variant in homozygosity in the TANGO2 gene. A stable sinus rhythm was achieved with metabolic and serum electrolytes optimization. ECG showed normalization of the QTc interval. Discussion: The full TANGO2-related phenotype emerges over time and the prognosis is linked to the appearance of ECG abnormalities. QT interval prolongation can lead to life-threatening ventricular tachycardias. The arrhythmia mechanism seems to be secondary to metabolite build-up in cardiomyocytes, which can explain the cardiac phenotype during the crisis which subsides after their resolution. In these patients, avoiding bradycardia is fundamental, since long QT-related TdP seems to be triggered by bradycardia and short-long-short ventricular premature beats (VPB). During an acute metabolic crisis, the management of arrhythmias relies on metabolic control.

Orthostatic Stress and Baroreflex Sensitivity: A Window into Autonomic Dysfunction in Lone Paroxysmal Atrial Fibrillation.

The abnormal neural control of atria has been considered one of the mechanisms of paroxysmal atrial fibrillation (PAF) pathogenesis. The baroreceptor reflex has an important role in cardiovascular regulation and may serve as an index of autonomic function. This study aimed to analyze the baroreceptor reflex's role in heart rate regulation during upright tilt (HUT) in patients with lone PAF. The study included 68 patients with lone PAF and 34 healthy individuals who underwent baroreflex assessment. Parameters such as baroreflex sensitivity (BRS), number of systolic blood pressure (BP) ramps, and the baroreflex effectiveness index (BEI) were evaluated. The study found that PAF patients had comparable resting BPs and heart rates (HRs) to healthy individuals. However, unlike healthy individuals, PAF patients showed a sustained increase in BP with an upright posture followed by the delayed activation of the baroreceptor function with a blunted HR response and lower BEI values. This indicates a pronounced baroreflex impairment in PAF patients, even at rest. Our data suggest that together with BRS, BEI could be used as a marker of autonomic dysfunction in PAF patients, making it important to further investigate its relationship with AF recurrence after ablation and its involvement in cardiovascular autonomic remodeling.