Electrophysiological Studies Research Articles

Sensorimotor Processing in Elite and Sub-Elite Adolescent Sprinters during Sprint Starts: An Electrophysiological Study.

Most studies on sprint performance have focused on kinematics and kinetics of the musculoskeletal system for adults, with little research on the central sensorimotor transmission and processes, especially for adolescent sprinters. This study aimed to determine whether differences in the integrity of the central auditory system and audiomotor transmissions between the elite and sub-elite adolescent sprinters may affect their performance in the 100 m time. Twenty-nine adolescent junior high school students, including elite national-class and sub-elite regional-class athletes, were assessed. Visual and auditory evoked potentials (VEP and AEP) as well as electroencephalography (EEG) and electromyography (EMG) were recorded and analyzed during a sprint start. The electrophysiological results clearly reveal differences in central auditory transmission between elite and sub-elite groups, and between sexes. There were significant differences between elite and sub-elite groups, and during a sprint start, the EEG activities for elite female and male athletes showed significant time-dependent differences in peak amplitudes following the three auditory cues (ready, set, and gunshot). These findings can provide coaches with a more comprehensive consideration for sports-specific selection based on the athletes' individual conditions, e.g., sensorimotor neuroplastic training for providing precise and efficient training methods to improve young sprinters' performance.

Daily exposure to chlordecone, an organochlorine pesticide, increases cardiac fibrosis and atrial fibrillation vulnerability

ContextChlordecone (CLD) is a carcinogenic organochlorine pesticide. CLD was shown to disturb the activity of cardiac Na+-K+-ATPase and Ca2+-Mg2+-ATPase. Conditions affecting these transmembrane pumps are often associated with cardiac arrhythmias (CA). However, little is known about the role of CLD on atrial fibrillation (AF) incidence, the most common type of CA. Hypotheses1) Daily ingestion of CLD induces arrhythmogenic cardiac remodeling. 2) A phase of CLD withdrawal can reduce CLD-induced AF susceptibility. MethodsAdult male Wistar rats (250 g-275 g) ingested daily-doses of CLD (0 μg/L, 0.1 μg/L, or 1 μg/L) diluted in their quotidian water for 4 weeks. From day (D)29 to D56, all rats received CLD-free water. Vulnerability to AF and cardiac function were evaluated at D28 and D56 by electrophysiological study, echocardiography, and optical-mapping. Levels of genes and proteins related to inflammation, fibrosis, and senescence were quantified by qPCR and immunoassays. ResultsTwenty-eight days of CLD exposure were associated with significantly increased AF vulnerability compared to CLD-free rats. Contamination with 1 μg/L CLD significantly reduced atrial conduction velocity (ERP, APD). CLD-weaning normalized food consumption and weight intake. However, after the CLD-withdrawal period of 28 days, AF inducibility, atrial inflammation (IL6, IL1β), and atrial fibrosis (Masson’s trichrome staining) remained significantly higher in rats exposed to 1 μg/L CLD compared to 0 μg/L. ConclusionsProlonged CLD ingestion provokes atrial conduction slowing and increased risk of AF. Although CLD-weaning, some persistent damages occurred in the atrium like atrial fibrosis and atrial senescence signals, which are accompanied by atrial inflammation and arrhythmogenicity.

Opto-CLIP reveals dynamic FMRP regulation of mRNAs upon CA1 neuronal activation.

Neuronal diversity and function are intricately linked to the dynamic regulation of RNA metabolism, including splicing, localization, and translation. Electrophysiologic studies of synaptic plasticity, models for learning and memory, are disrupted in Fragile X Syndrome (FXS). FXS is characterized by the loss of FMRP, an RNA-binding protein (RBP) known to bind and suppress translation of specific neuronal RNAs. Since molecular studies have demonstrated that synaptic plasticity in CA1 excitatory hippocampal neurons is protein-synthesis dependent, together these observations have suggested a potential role for FMRP in synaptic plasticity in FXS. To explore this model, we developed a new experimental platform, Opto-CLIP, to integrate optogenetics with cell-type specific FMRP CLIP and RiboTag in CA1 hippocampal neurons, allowing investigation of FMRP-regulated dynamics after neuronal activation. We tracked changes in FMRP binding and ribosome-associated RNA profiles 30 minutes after neuronal activation. Our findings reveal a significant reduction in FMRP-RNA binding to transcripts encoding nuclear proteins, suggesting FMRP translational inhibition may be de-repressed to allow rapid translational responses required for neuronal homeostasis. In contrast, FMRP binding to transcripts encoding synaptic targets were generally stable after activation, but all categories of targets demonstrated variability in FMRP translational control. Opto-CLIP revealed differential regulation of subsets of transcripts within CA1 neurons rapidly after depolarization, and offers promise as a generally useful platform to uncover mechanisms of RBP-mediated RNA regulation in the context of synaptic plasticity.

Impact of resident training on cardiac electrophysiological procedures

BackgroundModern management of cardiac arrhythmias often requires interventions in which young physicians must acquire a high level of expertise. However, concerns have been raised about the increase in side effects during procedures performed with resident involvement. AimThis study aims to identify the effects of resident training on cardiac electrophysiological procedures within a university centre. MethodsIn a single-centre study, cardiac arrhythmia procedures were reviewed retrospectively, and resident involvement was scrutinized. Univariate and multivariable models were built for the following outcomes: fluoroscopy time; operative time; length of hospitalization after procedure; and adverse events. ResultsWe reviewed 991 procedures, 574 without and 417 with resident involvement (650 cardiac pacemakers or defibrillators, 120 generator replacements, 188 electrophysiological studies and 153 radiofrequency ablations). Resident involvement was associated with an increase in fluoroscopy time: +1.7±0.4minutes (P<0.01) for pacemaker implantation; and +2.5±0.9minutes (P=0.01) for electrophysiological studies. Operative time was longer for electrophysiological studies (+10.8±4.9minutes; P=0.03) and pacing implantation (+8.4±2.2minutes; P<0.01). There was no significant association between resident training and adverse events (7.67 vs. 9.83%; P=0.28). ConclusionsCardiac electrophysiological procedures performed with resident involvement have a good safety profile. However, resident training modestly, but significantly, prolongs fluoroscopy time and operative time.

Characterization of a novel SCN5A mutation associated with long QT syndrome and arrhythmogenic right ventricular cardiomyopathy in a family.

Sudden cardiac death represents a significant diagnostic challenge for forensic pathologists, particularly in inherited arrhythmia syndromes or cardiomyopathies resulting from genetic defects. Molecular autopsies can reveal the underlying molecular etiology in such cases. In this study, we investigated a family with a history of sudden cardiac death to elucidate the molecular basis responsible for sudden cardiac death. The proband underwent a comprehensive forensic examination. Family members received thorough clinical evaluations, including electrocardiogram, Holter monitoring, echocardiography, and cardiac magnetic imaging. Whole exome sequencing and genetic analysis were performed on the deceased and her parents. In addition, Western blotting and patch-clamp recordings were employed to evaluate the expression and function of the mutant protein in vitro. Forensic examination diagnosed arrhythmogenic right ventricular cardiomyopathy (ARVC) as the cause of sudden death. Genetic analysis identified a novel missense mutation in SCN5A (p.V1323L), which was assessed as likely pathogenic by the ACMG guideline. Another family member carrying the mutation manifested long QT syndrome and mild cardiac fibrosis. The cellular electrophysiological study demonstrated that the mutation resulted in an enhanced late sodium current, suggesting it was a gain-of-function mutation. This study characterizes a novel SCN5A mutation that putatively causes long QT syndrome and may contribute to the development of ARVC. Our work expands the pathogenic spectrum of SCN5A variants and underscores the importance of molecular autopsy in sudden death cases, especially in those with suspected genetic disorders.

A child with recurrent headache, fever and diffuse meningeal enhancement on MRI.

Juvenile neurolupus presents primarily with neuropsychiatric manifestations which may also be the initial presentation. Such primary neuropsychiatric SLE (NPSLE) events are a consequence either of microvasculopathy and thrombosis, or of autoantibodies and inflammatory mediators. Diagnosis of NPSLE requires the exclusion of other causes, and clinical assessment directs the selection of appropriate investigations. These investigations include measurement of autoantibodies, analysis of cerebrospinal fluid, electrophysiological studies, neuropsychological assessment and neuroimaging to evaluate brain structure and function. In our patient, the disease presented with chronic headache initially diagnosed as migraine, followed by fever and paraparesis. Fundoscopy showed retinal haemorrhages. Investigations revealed anaemia, neutrophilic leucocytosis, thrombocytopenia and raised inflammatory markers (ESR 119mm/h CRP 58mg/L) and high globulin. MRI brain showed diffuse meningeal enhancement resembling meningitis but CSF analysis was normal. ANA and dsDNA were positive with low C3, C4. All diffuse meningeal enhancements may not be meningitis and one needs to corroborate all the clinical, biochemical and imaging analyses to come to a diagnosis.

Physiological analyses of swallowing changes due to chronic obstructive pulmonary disease in anesthetized male rats.

Chronic obstructive pulmonary disease (COPD) was previously known as chronic bronchitis and emphysema. It has various main symptoms, such as dyspnea, chronic cough, and sputum, and is often accompanied by dysphagia. Although many published clinical reports have described COPD-related dysphagia, the physiological mechanisms underlying swallowing changes due to COPD remain unclear. Therefore, we analyzed how COPD affects the swallowing reflex using COPD model rats. We performed an electrophysiological study of respiration and swallowing using COPD model induced by intratracheal administration of porcine pancreatic elastase and lipopolysaccharide in Sprague-Dawley male rats. To identify the respiration and swallowing responses, electromyographic activity was recorded from the diaphragm, digastric (Dig), and thyrohyoid (TH) muscles. We confirmed COPD using micro-computed tomography analysis and hematoxylin and eosin staining of the lungs. The duty cycle was defined as the ratio of the inspiration duration to the total respiratory duration. In COPD model rats, the duty cycle was significantly higher than that in control rats. The frequency of the swallowing reflex evoked by electrical stimulation of the superior laryngeal nerve during the inspiration phase was higher in COPD model rats than in control rats. Furthermore, long-term COPD altered Dig and TH muscle activity without pathological muscle change. Our results suggest that COPD increases the frequency of swallowing initiation during the inspiration phase. Furthermore, long-term COPD affects swallowing-related muscle activity without pathological muscle changes. These physiological changes may increase the risk of developing dysphagia. Further studies are necessary to clarify the mechanisms contributing to the functional changes in respiration and swallowing in COPD.

A novel ionic model for matured and paced atrial-like human iPSC-CMs integrating [formula omitted] and [formula omitted] currents

This work introduces the first atrial-specific in-silico human induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs) model, based on a set of phenotype-specific IKur,IKCa and IK1 membrane currents. This model is built on novel in-vitro experimental data recently published by some of the co-authors to simulate the paced action potential of matured atrial-like hiPSC-CMs. The model consists of a system of stiff ordinary differential equations depending on several parameters, which have been tuned by automatic optimization techniques to closely match selected experimental biomarkers. The new model effectively simulates the electronic in-vitro hiPSC-CMs maturation process, transitioning from an unstable depolarized membrane diastolic potential to a stable hyperpolarized resting potential, and exhibits spontaneous firing activity in unpaced conditions. Moreover, our model accurately reflects the experimental rate dependence data at different cycle length and demonstrates the expected response to a specific current blocker. This atrial-specific in-silico model provides a novel computational tool for electrophysiological studies of cardiac stem cells and their applications to drug evaluation and atrial fibrillation treatment.

Feasibility of transthoracic echocardiographic guidance for multicatheter electrophysiological mapping studies in horses.

Improved characterization of arrhythmias is based on minimally invasive catheterizations. However, these catheterizations have been poorly explored in horses because apart from 3-dimensional (3D) mapping systems, continuous guidance of the catheter's position with adequate detail is difficult using current imaging modalities. Position multiple electrophysiology catheters simultaneously at predetermined strategical positions in the heart using transthoracic echocardiographic guidance. Eight adult healthy horses. Observational study. Two electrophysiological studies were performed: 1 procedure with catheters positioned in the right heart in the standing sedated horse and 1 procedure under general anesthesia with catheters positioned in the left heart. Except for the coronary sinus catheter, each catheter positioning was simultaneously guided by right-parasternal transthoracic echocardiography and 3D electro-anatomical mapping. For each catheter position, a central imaging plane was taken as the starting point, after which the imaging probe was shifted, rotated, and angulated to visualize the catheter over its entire length, including its distal electrode. Catheter positionings in the right heart and left ventricle were successfully guided in the majority of the horses whereas catheter positionings in the left atrium, and especially the pulmonary veins, were challenging to guide echocardiographically. Ultrasound guidance of catheters to specific positions useful for electrophysiological mapping was feasible in the right heart and left ventricle but challenging for the left atrium. This approach creates a perspective for minimally invasive arrhythmia diagnosis without the need for a 3D mapping system. Left parasternal views and intracardiac echocardiography might provide better guidance for left atrial positions.

Abstract Tu079: The Calcium Handling Machinery and Electrophysiology is Remodeled in Friedreich’s Ataxia

Background: Friedreich's ataxia (FA) is a progressive neurodegenerative disorder. FA is caused by a deficiency in the frataxin protein due to an expansion of GAA repeats in the first intron of the frataxin gene. Reduced frataxin protein expression is thought to negatively affect mitochondrial function, leading to increased oxidative damage. Although FA is considered a neurodegenerative disorder, it is not completely understood why most patients present with left ventricular systolic dysfunction and die from cardiac events. Objective: The objective of our study is to determine whether abnormal calcium handling is a molecular mechanism of cardiac dysfunction in FA. Methods: We used the frataxin knock-out (KO) mouse model of FA as well as human heart samples from donors with FA and from unaffected donors. The expression of calcium-handling proteins was assessed using proteomics and westernblot. We used echocardiography and telemetric ECG to assess cardiac function in the mice. We also performed in-vivo programmed electrical stimulation (PES) to assess ventricular arrhythmogenesis in the mouse heart. Results: Proteomics and western blot showed that SERCA2, Ryr2, PLN, CASQ2, and CaMKII were downregulated and that the phosphorylation of Ryr2 and PLN (Ser16 and Thr17) were also significantly decreased in left ventricular tissue from humans with FA and from KO mice. The mitochondrial calcium handling proteins VDAC and MCU were upregulated in left ventricular tissue from humans with FA and from KO mice. On telemetric ECG, the RR tended to prolong in the KO animals compared to wild types (p=0.053), and heart rate variability analysis indicated heightened cardiac parasympathetic input. Echocardiography showed that the ejection fraction and fractional shortening were significantly decreased and left ventricular wall thickness and diameter were significantly increased in the KO mice. In PES, ventricular arrhythmogenesis was greater in KO mice compared to wild types. Conclusions: The reduced expression of calcium handling proteins may contribute to cardiac contractile and electrophysiological abnormalities in FA. Keywords: Friedreich's ataxia, SERCA2, Ryr2, PLN, CASQ2, and CaMKII.

Ventricular stimulation in patients with myotonic dystrophy type 1 may not predict future ventricular arrhythmias

Myotonic dystrophy type 1 (DM1) is associated with progressive conduction disease. Furthermore, DM1 patients are at risk ventricular arrhythmias (VAs), although prediction remains difficult. The 2022 Heart Rhythm Expert Consensus Statement gives a IIb recommendation to the use of electrophysiology study (EPS) to risk-stratify patients for VAs. The utility of EPS in predicting the development of VAs, however, has not been explored in this patient population. The study sought to examine the natural history of DM1 patients with positive and negative ventricular stimulation (v-stim) during EPS. Patients with a history of DM1 undergoing EPS with associated v-stim from 2008 to present were retrospectively identified. From 2008 to 2022, 26 consecutive DM1 patients presented for EPS with v-stim. Four v-stim protocols were positive for sustained or hemodynamically significant ventricular tachycardia (VT), one of which was induced with 600 doubles, the others with triple extrastimuli. A total of 22 of 26 subjects received a device implant, with 18 receiving permanent pacemakers and 4 implantable cardioverter-defibrillators. All 4 of the patients with positive v-stims underwent ICD implantation. After a mean of 5.7 years of follow-up, 7 patients had sustained VT, 6 of whom had negative v-stims. Of the 4 patients with positive v-stims, only 1 developed sustained VT in follow-up. Other than baseline QT interval at time of EPS, no baseline characteristics were significantly different between patients with and without subsequent VT. In this single center, v-stim in DM1 patients did not predict clinical VAs, as a vast majority of DM1 patients who developed VAs had negative v-stims.

Safety and feasibility of cardiac electrophysiology procedures in ambulatory surgery centers

BackgroundDespite their improved safety, by and large, cardiac electrophysiology procedures including catheter ablation (CA), are presently performed in hospital outpatient departments. ObjectiveThis large multicenter study investigated the safety and outcomes associated with various cardiac electrophysiology procedures performed at 6 ambulatory surgery centers (ASCs), primarily during the coronavirus disease 2019 pandemic under the Center for Medicare and Medicaid Services Hospitals Without Walls program. MethodsWe retrospectively analyzed the outcomes from consecutive electrophysiology procedures performed in ASCs with same-day discharge, including transesophageal echocardiography, cardioversion, cardiac implantable electronic device (CIED) implantation, electrophysiology studies, and CA for atrial fibrillation (AF), atrial flutter (AFL)/supraventricular tachycardia, ventricular premature complexes (VPCs), and atrioventricular node. ResultsAltogether, 4037 procedures were performed, including 779 transesophageal echocardiography/cardioversion procedures (19.3%), 1453 CIED implantation procedures (36.0%), 26 electrophysiology studies (0.6%), and 1779 CA procedures (44.1%) for AF (75.4%), AFL/supraventricular tachycardia (18.8%), VPC (4.7%), and atrioventricular node (1.1%). Overall, 80.2% of CA procedures were for left-sided atrial arrhythmias (AF/atypical AFL) requiring transseptal catheterization. Left-sided VPC ablation procedures (42.2%) were performed using a transseptal/retrograde approach. Adverse event rates were low, but comparable between CIED implantation and CA (0.76% vs 0.73%; P = .93), as were the incidences of urgent/unplanned postprocedure hospitalization (0.48% vs 0.45%; P = .89), respectively. Moreover, the adverse event rates in ASCs vs hospital outpatient departments did not differ for CIED (0.76% vs 0.65%; P = .71) or CA (0.73% vs 0.80%; P = .79). ConclusionThe results from this large multicenter study suggest that ASCs represent a safe and effective setting to perform a variety of cardiac electrophysiology procedures including CA. These findings bear important implications for healthcare delivery and policy.

Conflicting responses with simultaneous atrioventricular pacing. What is the mechanism?

A 60-year-old woman presented with recurrent episodes of palpitations, documented short RP, narrow QRS tachycardia and absence of preexcitation in the electrocardiogram during sinus rhythm. During an electrophysiology study, programmed stimulation induced a narrow QRS tachycardia with cycle length of 380 ms, VA interval of 164 ms and earliest atrial activation in the His region. Ventricular overdrive pacing failed to entrain the atrium even with isoprenaline infusion and atrial burst pacing repeatedly terminated the tachycardia. Difference in AH interval with pacing and SVT was 27 msec. Simultaneous atrial and ventricular pacing was done with atrial pacing from the high right atrium and showed a His signal as the first return electrogram suggestive of atrioventricular nodal reentrant tachycardia (AVNRT). The manoeuvre was repeated with atrial pacing from the proximal coronary sinus and showed an atrial signal as the first return electrogram suggestive of atrial tachycardia (AT). What is the explanation for the conflicting results of the two pacing maneuvers?

Behavioral and electrophysiological study in Colossoma macropomum treated with different concentrations of Nepeta cataria oil in an immersion bath revealed a therapeutic window for anesthesia.

The purpose of this study was to characterize the activity of essential oils from Nepeta Cataria (EON) at concentrations of 125 L-1, 150 L-1, 175 L-1, and 200 L-1 on the behavior of loss of the posture reflex and recovery of the posture reflex and electrocardiographic activity and recording of the opercular beat of Colossoma macropomum during immersion bathing for a period of 5min, in order to obtain a window for safe use during anesthesia. The fish (23.38 ± 3.5g) were assigned to the following experiments: experiment 1 (latency to loss and recovery of the posture reflex): (a) 125 L-1, (b) 150 L-1, (c) 175 L-1, and (d) 200 L-1 (n = 9) per group. Experiment 2 (electrocardiographic and heartbeat recordings): (a) control group; (b) vehicle control group (2ml of alcohol per liter of water), (c) 125 L-1, (d) 150 L-1, (e) 175 L-1, and (f) 200 L-1 (n = 9), per group. All the concentrations used showed efficacy in inducing loss of the posture reflex and reversibility with recovery of the posture reflex, but the electrocardiographic recordings indicated morphographic changes such as bradycardia during induction and p wave apiculation during recovery at the highest concentrations tested. In this way, we suggest a safe use window for short-term anesthesia with EON in the concentration range of 125 to 150 L-1 for juvenile Colossoma macropomum.

Cardiac Arrhythmias and Their Management: An In-Depth Review of Current Practices and Emerging Therapies.

Cardiac arrhythmias encompass a range of conditions characterized by abnormal heart rhythms, affecting millions globally and significantly contributing to morbidity and mortality. This review provides a comprehensive analysis of the current practices and emerging therapies in managing cardiac arrhythmias, covering their definition, classification, epidemiology, and the critical importance of effective management. It explores the pathophysiology underlying various arrhythmias, including the mechanisms of arrhythmogenesis, such as re-entry, automaticity, and triggered activity. The review details the latest diagnostic tools, including ECG, Holter monitoring, and electrophysiological studies, and discusses the clinical presentation of different arrhythmias, from supraventricular to ventricular types and bradyarrhythmias. We examine current pharmacological and non-pharmacological treatment strategies, such as antiarrhythmic drugs, catheter ablation, and device therapy, highlighting their efficacy and limitations. Furthermore, the review delves into emerging therapies, including advanced catheter ablation techniques, novel antiarrhythmic agents, gene therapy, and innovative device technologies like leadless pacemakers and subcutaneous implantable cardioverter-defibrillators (ICDs). Special considerations for managing arrhythmias in diverse populations, including pediatrics, the elderly, and pregnant women, are discussed. Additionally, the review explores future directions in arrhythmia management, emphasizing personalized medicine, artificial intelligence applications, and the integration of advanced technologies in diagnosis and treatment. By synthesizing current knowledge and prospects, this review aims to enhance understanding and promote advancements in the field, ultimately improving patient outcomes with cardiac arrhythmias.

Assessment of Upper Limb Nerves in Coronary Artery Disease Patients Undergoing Coronary Artery Bypass Graft.

Background Many patients experience pain in their upper limbs following surgical procedures involving median sternotomy, particularly those undergoing coronary artery bypass grafting (CABG). This type of pain, commonly reported by CABG patients, is often overlooked in hospital settings. Our study aims to address this issue by utilizing electrodiagnostic studies to understand this postoperative discomfort better. Objectives Cardiovascular procedures are standard and are trending toward endovascular interventions. Through this study, we aim to assess the occurrence of neurological issues in the upper limbs after CABGby comparing patients' preoperative and postoperative electrophysiological studies of the upper limb nerves. Materials and methods A prospective study was performed on 32 coronary artery disease (CAD) patients undergoing CABG to determine the effects of surgery on the upper limb nerves (median and ulnar nerves). We performed nerve conduction studies (NCS) and analyzed different parameters of both median and ulnar nerves pre and post-surgery. Results A change was noted in different NCS parameters of the median and ulnar nerves when we comparedthe pre and post-surgical values. The meanlatency of the median nerve sensory increased from a minimum of 3.01 millisecondsat the preoperative level to a maximum of 3.60 milliseconds when assessedtwo weeks post-surgery. The mean amplitude decreased from 16.49 microvolts to a minimum of 12.30 microvolts when assessed two weeks post-surgery. The meanvelocity decreased from 55.83 m/s at the preoperative value to a minimum of 45.03 m/sat the two weeks post-surgery assessment. The ulnar nerve also underwent similar changes. Conclusion The observed changes in latency, amplitude, and velocity might be attributed to various factors, including surgical trauma, inflammation, or alterations in the physiological state post-surgery. The sternotomy technique and the position and extent of opening the sternal retractor determine the prevalence of complications by causing injury to the medial and lateral cords of the brachial plexusafter CABG. Careful preoperative and postoperative assessments of patients may aid in preventing, minimizing, and treating these often undiagnosed complications.

Evaluation of cardiac clues in patients admitted to pediatric cardiology outpatient clinic with syncope

Background: In our study, we aimed to determine the incidence rates of children admitted to the pediatric cardiology outpatient clinic with syncope according to their etiologies; and especially to reveal the clues that distinguish cardiac syncope cases from other cases. Materials and Methods: The study was conducted by obtaining the information of 795 children aged 5-17 years who were diagnosed with syncope in the pediatric cardiology outpatient clinic of our tertiary university hospital between 01.01.2021 and 01.06.2024 from the data in our hospital automation system. Medical history of the patient and his/her family, syncopal event, physical examination findings, 12-lead electrocardiography (ECG), echocardiography, 24-hour rhythm holter and exercise ECG records were analyzed. Results: Cardiac syncope was 14.5% (10.8% arrhythmia and 3.7% structural heart disease) while noncardiac syncope was 85.5% (VVS 60.6%, OH 18.6%, situational 1% and 4.8% idiopathic). The most common conditions associated with cardiac syncope were a history of arrhythmia and heart disease, a family history of sudden death at a young age, and syncope associated with exercise-palpitations-chest pain. Rhythm holter test had a low diagnostic rate, while exercise ECG test had a high diagnostic rate. Conclusion: It is important to diagnose cardiac syncope as it can cause sudden death. Standard 12-lead ECG, echocardiography and rhythm holter examination should be performed in all suspected patients; exercise ECG, head-up tilt test, genetic arrhythmia/cardiomyopathy investigations and electrophysiologic study should be performed in selected cases. In addition, simultaneous ECG monitoring during electroencephalography (EEG) examination in patients presenting with atonic seizures will be very useful in terms of clarifying the etiology.

Electrophysiological differences of randomized deep sedation with dexmedetomidine versus propofol

BackgroundDexmedetomidine and propofol are common sedatives in intensive care units and for interventional procedures. Both may compromise sinus node function and atrioventricular conduction.The objective of this prospective, randomized study is to compare the effect of dexmedetomidine with propofol on sinus node function and atrioventricular conduction.MethodsIn a tertiary care center in Switzerland we included from September 2019 to October 2020 160 patients (65 ± 11 years old; 32% female) undergoing first ablation for atrial fibrillation by cryoballoon ablation or by radiofrequency ablation.Patients were randomly assigned to deep sedation with dexmedetomidine (DEX group) versus propofol (PRO group). A standard electrophysiological study was performed after pulmonary vein isolation with the patients still deeply sedated and hemodynamically stable.ResultsEighty patients each were randomized to the DEX and PRO group. DEX group patients had higher baseline sinus cycle length (1022 vs. 1138 ms; p = 0.003) and longer sinus node recovery time (SNRT400; 1597 vs. 1412 ms; p = 0.042). However, both corrected SNRT and normalized SNRT did not differ. DEX group patients had longer PR interval (207 vs. 186 ms; p = 0.002) and AH interval (111 vs. 95 ms, p = 0.008), longer Wenckebach cycle length of the atrioventricular node (512 vs. 456 ms; p = 0.005), and longer atrioventricular node effective refractory period (390 vs. 344 ms; p = 0.009). QRS width and HV interval were not different. An arrhythmia, mainly atrial fibrillation, was induced in 33 patients during the electrophysiological study, without differences among groups (20% vs. 15%, p = 0.533).ConclusionsDexmedetomidine has a more pronounced slowing effect on sinus rate and suprahissian AV conduction than propofol, but not on infrahissian AV conduction and ventricular repolarization. These differences need to be taken into account when using these sedatives.Trial registrationClinicalTrials.gov number NCT03844841, 19/02/2019

Clinical and molecular insights into A97S variants in hereditary transthyretin amyloid polyneuropathy in South China

Objective This study aims to delineate the clinical profiles of the hereditary transthyretin amyloid polyneuropathy (ATTRv-PN) patients with A97S variant from southern China and the molecular characteristics of this mutant protein. Methods Fifteen ATTRv-PN patients with heterozygous A97S and one patient with homozygous A97S were included in the study. Serum TTR tetramer concentration was quantified through ultra-performance liquid chromatography. Stabilities of A97S-TTR were assessed through in vitro urea-mediated tryptophan fluorescence experiments, and nephelometry was employed in drug response assessment. Results All patients were late-onset (≥50 years) with a mean age of onset at 59.26 ± 5.06 years old. Patients displayed a mixed phenotype featuring sensory-motor neuropathy with autonomic dysfunction and cardiac involvement, such as palpitations and chest pain. Electrophysiological studies showed generally axonal impairment of sensory and motor nerves. Tafamidis-treated patients showed significantly higher TTR tetramer concentrations, approaching healthy controls’ levels. In vitro assessment showed that A97S-TTR was more kinetically stable than the V122I-TTR, and tetramer stabilisers inhibited A97S-TTR amyloid formation by more than 70%. Conclusion This study provides valuable insights into the clinical and molecular characteristics of ATTRv-PN patients with A97S from South China, particularly regarding the differences in disease progression and stability features.

Cognitive assessment in multiple sclerosis patients: electrophysiological and subjective studies

BackgroundMultiple sclerosis (MS) is a persistent inflammatory condition affecting the central nervous system, often associated with cognitive impairment. This impairment frequently presents itself as deficiencies in short-term memory, attention, and information processing speed. This research was designed to investigate P300 in patients with MS and its correlation with their cognitive function and their state of fatigue and depression. This work included two groups: the control group (20 subjects) and the study group (30 MS patients). Evaluation encompassed clinical history, audiological assessment, the Expanded Disability Status Scale (EDSS), the fatigue severity scale, the Beck Depression Inventory, Addenbrooke’s cognitive examination, and P300 component of event-related potentials (ERPs).ResultsThe study group exhibited varying degrees of fatigue and depression. The scores of Addenbrooke’s cognitive evaluation were reduced in the MS group. The MS group exhibited a considerably prolonged P300 latency compared to the control group.ConclusionThis study demonstrates the effectiveness of P300 in assessing cognitive function in persons diagnosed with MS.