Invasive Electrophysiology Research Articles

Ventricular arrhythmias in association with athletic cardiac remodelling.

Athletes are predisposed to atrial arrhythmias but the association between intense endurance exercise training, ventricular arrhythmias (VAs) and sudden cardiac death is less well established. Thus, it is unclear whether the 'athlete's heart' promotes specific arrhythmias or whether it represents a more general pro-arrhythmogenic phenotype. Whilst direct causality has not been established, it appears possible that repeated exposure to high-intensity endurance exercise in some athletes contributes to formation of pro-arrhythmic cardiac phenotypes that underlie VAs. Theories regarding potential mechanisms for exercise-induced VAs include repeated bouts of myocardial inflammation and stretch-induced cellular remodelling. Small animal models provide some insights, but larger animal and human data are sparse. The current clinical approach to VAs in athletes is to differentiate those with and without structural or electrical heart disease. However, if the athlete's heart involves a degree of pro-arrhythmogenic remodelling, then this may not be such a simple dichotomy. Questions are posed by athletes with VAs in combination with extreme remodelling. Some markers, such as scar on magnetic resonance imaging, may point toward a less benign phenotype but are also quite common in ostensibly healthy athletes. Other clinical and invasive electrophysiology features may be helpful in identifying the at-risk athlete. This review seeks to discuss the association between athletic training and VAs. We will discuss the potential mechanisms, clinical significance and approach to the management of athletes with VAs.

Reasons for gender inequities in invasive electrophysiology: a survey on family issues and career paths of female and male electrophysiology fellows in Germany.

Female physicians are underrepresented in invasive electrophysiology (EP) for multiple reasons. Despite an increasing focus on the topic, it is unclear what aspects are predominant. We conducted a survey on career paths of current or former EP fellows in Germany to elucidate how gender and family affected their careers. 231 fellows (24.2% female) were invited. 110 participants completed the survey (30.9% female, mean age 41.0 ± 5.0 years, and 79.1% with children). Female and male participants with children reported similar career goals and achievements before parenthood, but afterwards women changed their career paths more often. Major reasons were personal priorities followed by lack of flexibility at work and at home. Women covered the majority of childcare. At the time of the survey, 80.0% of women and 96.4% of men with a former career goal of invasive EP were active in invasive EP. Independent of age, women were in lower-level positions, had accomplished fewer professional achievements, were less satisfied with their work and had fewer children. 56.5% of women did not feel supported by their employers regarding family issues. 82.6% reported there was no satisfactory day care. 69.6% were unable to continue to follow their career during pregnancy, mostly due to restrictions by employers (75.0%). Dedicated policies for pregnant workers or support programmes were scarce. Beside the distribution of childcare at home, lack of flexibility and support by employers as well as working and fluoroscopy restrictions during pregnancy hamper women in EP and should be addressed.

A pan-Europe comparative review of allied profession roles in cardiac science

Abstract Introduction Over the last 75 years, Cardiac Science (CS) has evolved into a widely practised Allied Profession (AP) throughout Europe. Despite this prominence, there are limited comparative works on AP titles, regulation, scope of practice (SoP) and training routes. The recognition of CS as a profession in the United Kingdom dates from 1948 when the Society for Cardiac Science and Technology (SCST) was established. In the UK, the AP role has evolved into Cardiac Physiologists with education at bachelor’s degree level and Clinical Scientists at master’s level. The SoP has also developed over time, leading to more advanced training and practice. Similar progression in professional titles, SoP, education and training routes also occurred in other European countries. Purpose To compare Allied Professions in Cardiac Science (APCS) including professional nomenclature, regulation, education, SoP, and pan-European identity. Methods Data were collected from November 2023 to January 2024. European and country databases were scrutinised to determine nomenclature, professional status, regulation, and educational requirements. Online translation was used when information was not available in English. Results The analysis of databases revealed 15 APCS roles (Table 1). In 60% of the countries, the role is officially recognised by a professional body that provides advocacy, education, training, and defines SoP (Figure 1). Moreover, 47% of countries operate a mandatory licensing or registration scheme. In 33% of countries, APCS roles are incorporated within the Biomedical Science profession. In the remaining countries, nine alternate titles are used to describe the discipline. In most cases (66%), education is at bachelor’s level, while in others, particularly where recognition is more limited, it is at a vocational level. In four countries (Austria, Ireland, Iceland, and The Netherlands), SoP is broadly in line with the UK, covering electrocardiography, echocardiography, haemodynamics for invasive procedures, implantable devices, and electrophysiology. Conversely, in other countries SoP varies and can include nuclear medicine (Sweden and Denmark) or perfusion and respiratory (Italy and Portugal). Some countries restrict SoP to defined roles such as pacemaker or echo technicians (Spain, Luxembourg, and Switzerland). Notably, Finland, France, and Norway, as well as most Eastern European countries do not recognise APCS roles. Conclusion While APCS roles are widely acknowledged in Europe, they lack visibility compared to other health professions. The variability in professional titles, education, and SoP constrain the development of a unified identity. Collaborative works connecting APCS roles across Europe may enhance identity, improve quality of care and raise the profile of this discipline.

Aberrancy masquerading as ventricular tachycardia: Importance of invasive electrophysiology study for diagnosis of wide complex tachycardias

BackgroundDifferentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with aberrancy based on the 12‑lead ECG alone can be imprecise. Implantable cardiac defibrillators (ICD) may be inserted for presumed VT, particularly in patients with syncopal presentation or atypical aberrancy patterns. Accurate diagnosis of these patients facilitated by an electrophysiology study (EPS) may alter diagnosis and management. MethodsWe present a prospective collection of cases across 3 cardiac centers of consecutive patients with WCT presumed to be VT who were referred for consideration of an ICD, and in whom further evaluation including an EPS ultimately demonstrated SVT with aberrancy as the culprit arrhythmia. Results22 patients were identified (17 male, mean age 50±13 years. Available rhythm data at the time of referral was presumptively diagnosed as monomorphic VT in 16 patients and polymorphic VT in 6 patients. Underlying structural heart disease was present in 20 (91%). EPS resulted in a diagnosis of SVT with aberrancy in all cases: comprising AV nodal re-entry tachycardia (n=10), orthodromic reciprocating tachycardia (n=3), focal atrial tachycardia (n=3), AF/AFL (n=3) and 'double fire' tachycardia (n=2). 21 (95%) patients underwent successful ablation. All patients remained free of arrhythmia recurrence at a median of 3.4 years of follow-up. ICD insertion was obviated in 18 (82%) patients, with 1 patient proceeding to ICD extraction. ConclusionSVT with atypical aberrancy may mimic monomorphic or polymorphic VT. Careful examination of all available rhythm data and consideration of an EPS can confirm SVT and obviate the need for ICD therapy.

Family issues in invasive electrophysiology - career paths of female and male EP fellows in Germany

Abstract Introduction Female doctors are underrepresented in invasive electrophysiology (EP) for multiple reasons. Despite an increasing focus on the topic, it is unclear what aspects are predominant and how they should be adressed to support women in EP. Methods We conducted a survey on career paths of current or former EP fellows in Germany to elucidate how gender and family affected their careers. The survey consisted of 11 questions on current work and family status, 20 on status before parenthood and the impact of children on career and 7 on the impact of pregnancy. 231 fellows (24% female) were invited. Results 110 participants completed the survey, 30% female and 70% male, mean age 39±5 and 42±5 years (p=0.012). Women and men had children in 68% and 84%, respectively (p=0.045). Before parenthood, both genders were at similar starting points in terms of working position, clinical experience, research activity and career goals. Of the 87% women and 86% men with a former career goal of invasive EP, 80% and 96% were active in invasive EP at the time of the survey, respectively (p=0.021). Women were in lower-level positions, had done fewer procedures, were less active in research and had achieved fewer degrees and qualifications. Women had fewer children and were less satisfied with their work. The associations were independent of age. Women reported to have changed their career paths after parenthood more often than men (p=0.004). Reasons were mainly changes in personal priorities, followed by lack of flexibility at work and at home. In contrast to men, women reported to cover the majority of childcare at home. Most women and men with children felt supported by their family, but did not feel supported by their employer in terms of work-family conflicts. 82% of employers offered some sort of daycare for children, but only 21% of women and 52% of men stated these were satisfactory. 13% of women and 3% of men received support by dedicated grants or programs. During pregnancy, 70% of women were unable to continue to follow their career. The most common reason was restrictions by their employer. 65% of women were not allowed to continue with invasive procedures, although 91% stated they wanted to. 74% were not allowed to work with radiation, alghough 78% wanted to. Only 22% stated there was a dedicated policy or program for pregnant interventionalists. Conclusion Women had to change their career paths more often than men after parenthood but reassuringly the majority was still able to continue with an invasive EP career. Despite a similar starting point of both genders before parenthood, women were able to accomplish fewer professional achievements and were less satisfied with their work. A fundamental reason seems to be the distribution of childcare at home, but also a lack of flexibility and support by employers as well as working restrictions during pregnancy. These points should be adressed to further support women in EP.

Using AI to identify left ventricular ejection fraction from the ECG: The SOLOMAX (SOciaL NetwOrk of MedicAl Experiences) project

Aim: The interest in machine learning-based algorithms in the cardiovascular field is rapidly growing, especially for diagnostic and prognostic purposes. Recent evidence has demonstrated that certain electrocardiographic (ECG) parameters are predominantly associated with systolic function, estimated as left ventricular ejection fraction (LVEF) by echocardiography, albeit with still relatively low accuracy. Consequently, this study aims to develop an AI-based model capable of predicting LVEF from ECG data in an Italian population. Methods: Within the SOLOMAX project, we collected paired ECG-Echocardiography exams from 105 patients (64.82±16.02y;62.86%male). Precisely, we excluded patients with atrial fibrillation at the time of the ECG, PMK or electrostimulated rhythm, valve prostheses, previous cardiac surgery, O2 therapy or COPD, previous ablation or invasive electrophysiology procedures, currently hospitalized for Takotsubo or ACS, heart failure exacerbation, inotropic therapy, ACS over the last 3 months. We recorded anthropometric, clinical, biochemical, ECG, and Echocardiography parameters. The collected data was studied using AI-based techniques to create a new model to predict LVEF from ECG. Using an approach based on evolutionary algorithms, genetic programming was used. This approach solves a symbolic regression problem through genetic algorithms and provides a mathematical model of the relationship between ECG parameters and LVEF. The formula obtained was then used to build a simple explainable classifier, which provides a global interpretation of the link between ECG parameters and LVEF. Results: The performance of the proposed approach and the reliability of the results were assessed using the k-fold cross-validation method and by estimating standard metrics derived from the confusion matrix associated with a binary classifier, that is, accuracy, sensitivity, specificity, precision, and F-Measure. The proposed approach consistently demonstrated its ability to distinguish patients with preserved LVEF from those with reduced LVEF. Each metric averaged across all experiments scored approximately 95%. Furthermore, in the expression generated by the AI model, the axes of the P, QRS, and T waves play a prominent role, as they are likely to provide a better interpretation of the three-dimensional cardiac geometry and, consequently, cardiac function. Conclusions: AI applied to ECG data can be used to create cost-effective diagnostic and predictive tools for assessing LVEF. Indeed, the obtained formula highlights the relationship between ECG parameters and LVEF, as well as its complexity, which can aid in detecting heart diseases.

The Effect of the Use of Activation 3D Mapping on the Patient X-Ray Load During Radiofrequency Ablation of Typical Atrial Flutter

Supraventricular macro re-entry tachyarrhythmias occupy the leading places among all types of tachyarrhythmias. The most common in this category is typical atrial flutter (AFL). This heart rhythm disorder has a negative impact on the patients’ quality of life. Its complications can lead to disability and death due to possible thromboembolism. Therapeutic treatment is limited in effectiveness. The main method of intervention is catheter radiofrequency ablation (RFA). The standard approach of RFA of AFL is performed without the use of navigation systems under fluoroscopy guidance. However, this results in an increased radiation exposure to the patient and the medical personnel. Modern technologies in the field of invasive electrophysiology make it possible to create anatomical models of heart and reproduce the spread of electrical excitation. However, the routine use of additional navigation methods remains controversial.
 The aim. To compare the duration of RFA of typical AFL and radiation exposure with the use of anatomical and propagation mapping.
 Materials and methods. This study is based on the analysis of the treatment results obtained for 53 patients at the National Amosov Institute of Cardiovascular Surgery in the period from 2014 to 2023. Depending on imaging methods, the patients were divided into two groups. The first group included 27 patients with an anatomical mapping of the right atrium. The second group included 26 patients with propagation mapping.
 Results. In all the patients we have achieved a bidirectional conduction block through cavotricuspid isthmus. In the first group, the total duration of confirming the diagnosis and creating the anatomical model was 312 ± 26 seconds. The mean time to the moment of AFL termination and restoration of sinus rhythm was 230 ± 19 seconds. The average duration of the procedure was 41.5 ± 3.5 minutes, the average fluoroscopy time was 120 ± 10 seconds, the average dose area product (DAP) was 15 ± 1.3 Gy·cm2. In the second group, the average time for creating a 3D propagation model of right atrium and verifying the diagnosis was 748 ± 65 seconds. The average time from the first application to the termination of tachycardia was 227 ± 20 seconds. The average duration of the procedure was 55 ± 4.7 minutes, X-ray time was 93 ± 8 seconds, average DAP was 13 ± 1.1 Gy·cm2. The duration of the procedure in the second group was significantly longer (p = 0.03), however, the radiation exposure and DAP were not statistically different (p = 0.31) between the observation groups.
 Conclusions. The use of propagation mapping increases the time of the procedure by 24.5% and does not give a significant advantage in reducing the radiation exposure. The use of a navigation system during cavotricuspid isthmus RFA is recommended for concomitant radical treatment of complex supraventricular arrhythmias, such as atrial fibrillation.

Historical development of diagnosis of bradyarrhythmias : The early years of clinical electrophysiology in Germany

The introduction of His bundle electrography by Benjamin Scherlag (New York) in 1969, together with programmed stimulation of the heart by Philip Coumel (Paris) in 1967, and Hein Wellens (Amsterdam) in 1972, were decisive turning points on the way to invasive electrophysiology and the development of an independent, now distinctly interventional subspecialty of cardiology. The main topic of the 1970s was bradycardic arrhythmias, promoted by pacemaker therapy, which had been introduced just over 10years earlier. The recording of the potentials of the bundle of His and other recording locations in the atria and ventricles allowed adifferentiated assessment of the excitation process and the refractory periods. High-rate atrial stimulation to determine sinus node recovery time and premature stimulation to determine sinoatrial conduction time were developed to analyze sinoatrial node function. This article describes the introduction of His bundle electrography in agradually increasing number of centers in Germany and their scientific contribution.

Arrhythmic Mitral Valve Prolapse and Sports Activity: Pathophysiology, Risk Stratification, and Sports Eligibility Assessment.

Although mitral valve prolapse (MVP) is the most prevalent valvular abnormality in Western countries and generally carries a good prognosis, a small subset of patients is exposed to a significant risk of malignant ventricular arrhythmias (VAs) and sudden cardiac death (SCD), the so-called arrhythmic MVP (AMVP) syndrome. Recent work has emphasized phenotypical risk features of severe AMVP and clarified its pathophysiology. However, the appropriate assessment and risk stratification of patients with suspected AMVP remains a clinical conundrum, with the possibility of both overestimating and underestimating the risk of malignant VAs, with the inappropriate use of advanced imaging and invasive electrophysiology study on one hand, and the catastrophic occurrence of SCD on the other. Furthermore, the sports eligibility assessment of athletes with AMVP remains ill defined, especially in the grey zone of intermediate arrhythmic risk. The definition, epidemiology, pathophysiology, risk stratification, and treatment of AMVP are covered in the present review. Considering recent guidelines and expert consensus statements, we propose a comprehensive pathway to facilitate appropriate counseling concerning the practice of competitive/leisure-time sports, envisioning shared decision making and the multidisciplinary "sports heart team" evaluation of borderline cases. Our final aim is to encourage an active lifestyle without compromising patients' safety.

Clonal Hematopoiesis of Indeterminate Potential With Loss of Tet2 Enhances Risk for Atrial Fibrillation Through Nlrp3 Inflammasome Activation.

Clonal hematopoiesis of indeterminate potential (CHIP), a common age-associated phenomenon, associates with increased risk of both hematological malignancy and cardiovascular disease. Although CHIP is known to increase the risk of myocardial infarction and heart failure, the influence of CHIP in cardiac arrhythmias, such as atrial fibrillation (AF), is less explored. CHIP prevalence was determined in the UK Biobank, and incident AF analysis was stratified by CHIP status and clone size using Cox proportional hazard models. Lethally irradiated mice were transplanted with hematopoietic-specific loss of Tet2, hematopoietic-specific loss of Tet2 and Nlrp3, or wild-type control and fed a Western diet, compounded with or without NLRP3 (NLR [NACHT, LRR {leucine rich repeat}] family pyrin domain containing protein 3) inhibitor, NP3-361, for 6 to 9 weeks. Mice underwent in vivo invasive electrophysiology studies and ex vivo optical mapping. Cardiomyocytes from Ldlr-/- mice with hematopoietic-specific loss of Tet2 or wild-type control and fed a Western diet were isolated to evaluate calcium signaling dynamics and analysis. Cocultures of pluripotent stem cell-derived atrial cardiomyocytes were incubated with Tet2-deficient bone marrow-derived macrophages, wild-type control, or cytokines IL-1β (interleukin 1β) or IL-6 (interleukin 6). Analysis of the UK Biobank showed individuals with CHIP, in particular TET2 CHIP, have increased incident AF. Hematopoietic-specific inactivation of Tet2 increases AF propensity in atherogenic and nonatherogenic mouse models and is associated with increased Nlrp3 expression and CaMKII (Ca2+/calmodulin-dependent protein kinase II) activation, with AF susceptibility prevented by inactivation of Nlrp3. Cardiomyocytes isolated from Ldlr-/- mice with hematopoietic inactivation of Tet2 and fed a Western diet have impaired calcium release from the sarcoplasmic reticulum into the cytosol, contributing to atrial arrhythmogenesis. Abnormal sarcoplasmic reticulum calcium release was recapitulated in cocultures of cardiomyocytes with the addition of Tet2-deficient macrophages or cytokines IL-1β or IL-6. We identified a modest association between CHIP, particularly TET2 CHIP, and incident AF in the UK Biobank population. In a mouse model of AF resulting from hematopoietic-specific inactivation of Tet2, we propose altered calcium handling as an arrhythmogenic mechanism, dependent on Nlrp3 inflammasome activation. Our data are in keeping with previous studies of CHIP in cardiovascular disease, and further studies into the therapeutic potential of NLRP3 inhibition for individuals with TET2 CHIP may be warranted.

Thromboembolism prophylaxis practices of pediatric and congenital electrophysiologists during invasive electrophysiology studies: A PACES survey.

Thromboembolic events related to invasive electrophysiology studies, while rare, can have devastating consequences. Use of systemic anticoagulation for a pediatric or adult-congenital invasive electrophysiology study is recommended, however there is no established standard of practice in this population. To report on procedural practices for thromboembolism prophylaxis during invasive electrophysiology studies for pediatric patients and adults with congenital heart disease. An anonymous web-based survey was sent to the members of the Pediatric and Congenital Electrophysiology Society. The survey focused on pre-procedural, intra-procedural, and post-procedural thromboembolism prophylaxis practices during invasive electrophysiology studies. Significant practice variation was defined as <90% concordance among respondents. Survey was completed by 73 members; 52 (71%) practicing in the United States, 65 (89%) practicing in an academic institution, and 14 (19%) in an institution that performs more than 200 invasive electrophysiology procedures annually. Responses showed significant variation in practice. Prior to an invasive electrophysiology procedure, 25% discontinue aspirin while 47% discontinue anticoagulants. Heparin is given for all procedures by 32%. When heparin is administered, the first dose is given by 32% after sheaths are placed, 42% after crossing into the systemic atrium, and 26% just prior to systemic-side ablation. Most target an activated clotting time between 200-300 seconds. Post systemic-side ablation, 58% do not initiate a heparin infusion. Post-procedural oral agents were initiated on day of procedure by 34% of respondents and on post-procedure day 1 by 53%. If treating with aspirin, 74% use low-dose (3-5mg/kg or 81mg daily), and 68% treat for 4-6weeks. There is significant variation in thromboembolism prophylaxis for invasive EP studies among pediatric and congenital electrophysiologists. Further studies are needed to optimize the management of thromboembolism prophylaxis in this population.

Praziquantel activates a native cation current in Schistosoma mansoni

IntroductionPraziquantel (PZQ), an anthelmintic drug discovered in the 1970s, is still used to treat schistosomiasis and various other infections caused by parasitic flatworms. PZQ causes a triad of phenotypic effects on schistosome worms – rapid depolarization, muscle contraction, and damage throughout the worm tegument. The molecular target mediating these effects has been intimated as a Ca2+-permeable ion channel, but native currents evoked by PZQ have not been reported in any schistosome cell type. The properties of the endogenous PZQ activated conductance therefore remain unknown. MethodsHere, invasive electrophysiology was used to probe for responses to PZQ from different locales in a living schistosome worm.Results and discussionNo direct response was seen in tegument-derived vesicles, or from the sub-tegumental muscle layer despite the presence of voltage-operated currents. However, PZQ rapidly triggered a sustained, non-selective cation current in recordings from neuronal tissue, targeting both the anterior ganglion and the main longitudinal nerve cord. The biophysical signature of this PZQ-evoked current resolved at single channel resolution matched that of a transient receptor potential ion channel named TRPMPZQ, recently proposed as the molecular target of PZQ. The endogenous PZQ-evoked current was also inhibited by a validated TRPMPZQ antagonist. PZQ therefore is a neuroactive anthelmintic, causing a sustained depolarization through ion channels with the characteristics of TRPMPZQ.

Novel training concept utilizing a real world-like EP simulator

Abstract Background Training in the field of invasive cardiac electrophysiology (EP) is challenging and requires intellectual skills related to the interpretation of intracardiac electrograms. Classic approach to education of young electrophysiologists focused solely on theoretical knowledge and overseen procedures in patients as no real life like simulation of complete diagnostic and therapeutic EP studies was available. Purpose The purpose of this study was to assess a novel tool for EP training based on fully interactive, online simulator providing real clinical experience to the users. Methods EP Simulator replicates EP recording system routinely used in cardiac electrophysiology laboratories and therefore enable easier transition from training to clinical situation. Users are able to access a fully functional system with simulated surface electrocardiogram and intracardiac electrograms mimicking signals recorded by a catheter located at high right atrium, His bundle, coronary sinus, and right ventricular apex. Normal electrophysiology study and the following cardiac arrhythmias are available for simulation: sick sinus syndrome, AV conduction blocks, atrial ectopy, atrial flutter and fibrillation, atrio-ventricular and atrio-ventricular nodal reentrant tachycardia and ventricular tachycardias. Evaluation by 40 electrophysiologists (mean experience 8±6y) from 16 countries was collected via online questionnaire. Results Realism of ECG signals was described as excellent or very good by 90% of responders, realism of intracardial signals by 82.5%. Realism of signal interactions and user experience was judged as excellent or very good by 75% and 70%, respectively. 100% of users agree definitely or mostly that EP Simulator helps to translate theoretical into practical knowledge. 97.5% of responders would include it in EP training programs as it is extremely or very useful for training purposes in opinion of 87.5%. 72.5% of responders think that training on EP simulator can potentially reduce rate of complications. In 87.5% the overall experience of EP simulator was completely or mostly satisfying and it would be recommended by 100% of respondents. Conclusion EP simulator is a feasible tool for training of young electrophysiologist and it may be potentially included in cardiologist curriculum. We should particularly emphasize the positive respondents’ evaluation of EP simulator overall realism. Further systematic evaluation of the training progress is needed.

Abstract 15963: A Novel SGK1 Inhibitor (SGK1-I), Prevents Obesity-Related Atrial Fibrillation

Introduction: Obesity is an important risk factor for atrial fibrillation. We have previously demonstrated the protective effect of genetic SGK1 inhibition in a mouse model of obesity-related atrial fibrillation (AF). SGK1-I is a novel and potent SGK1 inhibitor that has been shown to reduce late sodium current and has currently entered clinical trials as a potential treatment of long QT syndrome. Hypothesis: We sought to assess the efficacy of pharmacologic SGK1 inhibition in a mouse model of obesity-related AF. Methods: Wild type C57/Bl6 mice were fed a high fat diet containing 60% cholesterol (by calories) compounded with (HFD-SGK1i) or without (HFD) SGK1-I for 10 weeks. After feeding, the mice were assayed with invasive electrophysiology studies (EPS), optical mapping, and biochemical assays. Results: There were no significant differences in rate of weight gain, final body weight, fasting glucose, glucose tolerance, or tail-cuff blood pressure between the two groups of mice throughout the study. During EPS, there were no differences in nodal (sinus and atrio-ventricular) function or tissue (atrial/ventricular) refractory periods. However, HFD-SGK1i mice were significantly protected from obesity-related inducible AF during EPS, with a lower rate of AF inducibility (5.7% versus 1.5%, p&lt;0.0001) and a lower total AF burden (35±54 versus 5.5±10.7 s, p=0.04). Optical mapping revealed abbreviated right (RA), but not left (LA), atrial action potential duration (APD) and attenuated inter-atrial APD differences in HFD-SGK1i mice as compared to HFD mice. In this context, Western blotting data demonstrated greater RA (versus LA) SGK1 activity/expression resulting from HFD, suggesting that SGK1 signaling may contribute to inter-atrial heterogeneity caused by HFD. Finally, protein expression of NLRP3 inflammasome components, Caspase-1 and ASC, as well as TGF-β expression were decreased in the SGK1-1 group; consistent with anti-inflammatory and anti-fibrotic signaling resulting from SGK1-I treatment. Conclusion: SGK1-I protects mice from obesity-related AF. These data further highlight SGK1 and its inhibition as a compelling target in cardiac arrhythmogenesis.

Abstract 17087: Novel Machine Learning Models to Enhance and Automate Cardiovascular Outpatient Triage for Patients With Atrial Fibrillation

Introduction: Atrial fibrillation (AF) is the most prevalent arrhythmia, placing a substantial burden on the healthcare system. Patients with AF are cared for in a variety of settings including primary care and cardiology clinics, while some require cardiac electrophysiology (EP) clinics offering specialized drugs or procedures. Appropriate triage of AF referrals to these specific clinics will lead to timely and appropriate care and reduce inefficiency in the health system. Goal: To develop a machine learning (ML) model to triage AF referrals to a large Cardiology center to either the Cardiology or EP clinic based on likelihood of requiring an invasive EP procedure or initiation of antiarrhythmic drug. Methods: We retrospectively analyzed 6,755 patients who were referred to CV with referral diagnosis of AF (mean age 70 ± 11 years, 66% male). We employed multiple input variables to predict the suitability for EP clinic defined as need for initiating an antiarrhythmic drug or an invasive EP procedure. These encompassed patient demographics, relevant comorbidities, medications, prior procedures, medical notes analyzed using natural language processing (NLP), and Holter monitoring data. Results: For internal referrals, XG boost model performed the best with AUC at 79%, accuracy at 72%, and F1 score at 68%. This model produces true positive (TP) at 68% and true negative (TN) at 74%, which was better in comparison with triaging using NLP only (AUC = 69%, TP = 58%, TN = 61%), Holter only (AUC = 52%, TP = 51%, TN = 77%), and NLP/Holter (AUC = 67%, TP = 60%, TN = 60%). When supplementing ML model with Holter readings on average HR ≥ 100 and maximum HR ≥ 150, the results can be improved to TP at 70% and TN at 73%. Conclusions: Our model effectively identifies patients who are more likely to require specialized EP care, enabling the automation and increased efficiency of the AF referral triage process. Prospective validation studies are paramount in determining the true value of this tool.

Hypertrophic Cardiomyopathy and Ventricular Preexcitation in the Young: Cause and Accessory Pathway Characteristics.

The cause of hypertrophic cardiomyopathy (HCM) in the young is highly varied. Ventricular preexcitation (preexcitation) is well recognized, yet little is known about the specificity for any cause and the characteristics of the responsible accessory pathways (AP). Retrospective cohort study of patients <21 years of age with HCM/preexcitation from 2000 to 2022. The cause of HCM was defined as isolated HCM, storage disorder, metabolic disease, or genetic syndrome. Atrioventricular AP (true AP) were distinguished from fasciculoventricular fibers (FVF) using standard invasive electrophysiology study criteria. AP were defined as high risk if any of the following were <250 ms: shortest preexcited RR interval in atrial fibrillation, shortest paced preexcited cycle length, or anterograde AP effective refractory period. We identified 345 patients with HCM and 28 (8%) had preexcitation (isolated HCM, 10/220; storage disorder, 8/17; metabolic disease, 5/19; and genetic syndrome, 5/89). Six (21%) patients had clinical atrial fibrillation (1 with shortest preexcited RR interval <250 ms). Twenty-two patients underwent electrophysiology study which identified 23 true AP and 16 FVF. Preexcitation was exclusively FVF mediated in 8 (36%) patients. Five (23%) patients had AP with high-risk conduction properties (including ≥1 patient in each etiologic group). Multiple AP were seen in 8 (36%) and AP plus FVF in 10 (45%) patients. Ablation was acutely successful in 13 of 14 patients with recurrence in 3. One procedure was complicated by complete heart block after ablation of a high-risk midseptal AP. There were significant differences in QRS amplitude and delta wave amplitude between groups. There were no surface ECG features that differentiated AP from FVF. Young patients with HCM and preexcitation have a high likelihood of underlying storage disease or metabolic disease. Nonisolated HCM should be suspected in young patients with large QRS and delta wave amplitudes. Surface ECG is not adequate to discriminate preexcitation from a benign FVF from that secondary to potentially life-threatening AP.

Robotic-Assisted Solutions for Invasive Cardiology, Cardiac Surgery and Routine On-Ward Tasks: A Narrative Review.

Robots are defined as programmable machines that can perform specified tasks. Medical robots are emerging solutions in the field of cardiology leveraging recent technological innovations of control systems, sensors, actuators, and imaging modalities. Robotic platforms are successfully applied for percutaneous coronary intervention, invasive cardiac electrophysiology procedures as well as surgical operations including minimally invasive aortic and mitral valve repair, coronary artery bypass procedures, and structural heart diseases. Furthermore, machines are used as staff-assisting tools to support nurses with repetitive clinical duties i.e., food delivery. High precision and resolution allow for excellent maneuverability, enabling the performance of medical procedures in challenging anatomies that are difficult or impossible using conventional approaches. Moreover, robot-assisted techniques protect operators from occupational hazards, reducing exposure to ionizing radiation, and limiting risk of orthopedic injuries. Novel automatic systems provide advantages for patients, ensuring device stability with optimized utilization of fluoroscopy. The acceptance of robotic technology among healthcare providers as well as patients paves the way for widespread clinical application in the field of cardiovascular medicine. However, incorporation of robotic systems is associated with some disadvantages including high costs of installation and expensive disposable instrumentations, the need for large operating room space, and the necessity of dedicated training for operators due to the challenging learning curve of robotic-assisted interventional systems.

Shared Decision Making and Cardioneuroablation Allow Discontinuation of Permanent Pacing in Patients with Vagally Mediated Bradycardia.

Safe discontinuation of pacemaker therapy for vagally mediated bradycardia is a dilemma. The aim of the study was to present the outcomes of a proposed diagnostic and therapeutic process aimed at discontinuing or not restoring pacemaker therapy (PPM) in patients with vagally mediated bradycardia. The study group consisted of two subgroups of patients with suspected vagally mediated bradycardia who were considered to have PPM discontinued or not to restore their PPM if cardioneuroablation (CNA) would successfully treat their bradycardia. A group of 3 patients had just their pacemaker explanted but reimplantation was suggested, and 17 patients had preexisting pacemakers implanted. An invasive electrophysiology study was performed. If EPS was negative, extracardiac vagal nerve stimulation (ECVS) was performed. Then, patients with positive ECVS received CNA. Patients with an implanted pacemaker had it programmed to pace at the lowest possible rate. After the observational period and control EPS including ECVS, redo-CNA was performed if pauses were induced. The decision to explant the pacemaker was obtained based on shared decision making (SDM). After initial clinical and electrophysiological evaluation, 17 patients were deemed eligible for CNA (which was then performed). During the observational period after the initial CNA, all 17 patients were clinically asymptomatic. The subsequent invasive evaluation with ECVS resulted in pause induction in seven (41%) patients, and these patients underwent redo-CNA. Then, SDM resulted in the discontinuation of pacemaker therapy or a decision to not perform pacemaker reimplantation in all the patients after CAN. The pacemaker was explanted in 12 patients post-CNA, while in 2 patients explantation was postponed. During a median follow-up of 18 (IQR: 8-22) months, recurrent syncope did not occur in the CNA recipients. Pacemaker therapy in patients with vagally mediated bradycardia could be discontinued safely after CNA.

Extensive topographic remapping and functional sharpening in the adult rat visual pathway upon first visual experience.

Understanding the dynamics of stability/plasticity balances during adulthood is pivotal for learning, disease, and recovery from injury. However, the brain-wide topography of sensory remapping remains unknown. Here, using a first-of-its-kind setup for delivering patterned visual stimuli in a rodent magnetic resonance imaging (MRI) scanner, coupled with biologically inspired computational models, we noninvasively mapped brain-wide properties-receptive fields (RFs) and spatial frequency (SF) tuning curves-that were insofar only available from invasive electrophysiology or optical imaging. We then tracked the RF dynamics in the chronic visual deprivation model (VDM) of plasticity and found that light exposure progressively promoted a large-scale topographic remapping in adult rats. Upon light exposure, the initially unspecialized visual pathway progressively evidenced sharpened RFs (smaller and more spatially selective) and enhanced SF tuning curves. Our findings reveal that visual experience following VDM reshapes both structure and function of the visual system and shifts the stability/plasticity balance in adults.

Cardiac tamponades related to interventional electrophysiology procedures are associated with higher risk of short-term hospitalization for pericarditis but favourable long-term outcome.

To investigate the association of iatrogenic cardiac tamponades as a complication of invasive electrophysiology procedures (EPs) and mortality as well as serious cardiovascular events in a nationwide patient cohort during long-term follow-up. From the Swedish Catheter Ablation Registry between 2005 and 2019, a total of 58 770 invasive EPs in 44 497 patients were analysed. From this, all patients with periprocedural cardiac tamponades related to invasive EPs were identified (n = 200; tamponade group) and matched (1:2 ratio) to a control group (n = 400). Over a follow-up of 5 years, the composite primary endpoint-death from any cause, acute myocardial infarction, transitory ischaemic attack (TIA)/stroke, and hospitalization for heart failure-revealed no statistically significant association with cardiac tamponade [hazard ratio (HR) 1.22 (95% CI, 0.79-1.88)]. All single components of the primary endpoint as well as cardiovascular death revealed no statistically significant association with cardiac tamponade. Cardiac tamponade was associated with a significantly higher risk with hospitalization for pericarditis [HR 20.67 (95% CI, 6.32-67.60)]. In this nationwide cohort of patients undergoing invasive EPs, iatrogenic cardiac tamponade was associated with an increased risk of hospitalization for pericarditis during the first months after the index procedure. In the long-term, however, cardiac tamponade revealed no significant association with mortality or other serious cardiovascular events.