Search

The electrical arrhythmogenic substrate underlying the most common cardiac arrhythmia atrial fibrillation (AF) may consist of conduction disorders, low-voltage areas, or fractionated potentials. High-density and resolution epicardial mapping (HDREM) approaches have been introduced to quantify and visualize electrophysiological properties of the atria. These approaches are essential for obtaining innovative insights into arrhythmogenic substrates and identifying novel targets for therapy. The aim of this review is to summarize and discuss the (1) contribution of HDREM studies to the knowledge on atrial arrhythmogenesis and (2) future applications of HDREM of atria in daily clinical practice. [ABSTRACT FROM AUTHOR]

Background: Kawasaki Disease (KD) is self-limited vasculitis, the main consequence of which may be involvement of the coronary arteries, especially in patients without treatment. It is estimated that coronary artery aneurysms occur in 15% to 25% of untreated children. Patients with coronary aneurysms may remain asymptomatic for years. The first symptom may be life-threatening sudden cardiac arrest or myocardial ischaemia. Methods: We report a case of a 17-year-old boy with an insignificant past medical history who presented with sudden cardiac arrest. Results: During diagnostics, channelopathies, structural heart defects, drug abuse, and myocardial infarction were excluded. The patient underwent coronary angiography, confirmed by CT angiogram of the coronary vessels, which revealed most likely ruptured, clotted, well-calcified aneurysm of the left anterior descending artery (LAD) with collateral circulation, probably a consequence of untreated Kawasaki disease in early childhood. Conclusions: Complications of KD should be considered in the differential diagnosis of sudden cardiac arrest, especially in a young person. [ABSTRACT FROM AUTHOR]

Ventricular arrhythmias originating from the papillary muscle of the ventricles are complex clinical problems. Catheter ablation has the potential to cure these arrhythmias. However, the procedure is usually challenging due to the specific anatomy, catheter instability and difficulty in localization of the origin of the arrhythmias. Intracardiac echocardiography (ICE) has been reported to be the suitable imaging method for assessing the location of focus in papillary muscles. We used transthoracic echocardiography (TTE), as a noninvasive cost-effective imaging supporting modality, in combination with 3D mapping to guide the exact localization and successful ablation of papillary muscle-originating premature ventricular contractions (PVCs). [ABSTRACT FROM AUTHOR]

Electrocardiographic (ECG) R-peak detection is essential for every sensor-based cardiovascular health monitoring system. To validate R-peak detectors, comparing the predicted results with reference annotations is crucial. This comparison is typically performed using tools provided by the waveform database (WFDB) or custom methods. However, many studies fail to provide detailed information on the validation process. The literature also highlights inconsistencies in reporting window size, a crucial parameter used to compare predictions with expert annotations to distinguish false peaks from the true R-peak. Additionally, there is also a need for uniformity in reporting the total number of beats for individual or collective records of the widely used MIT-BIH arrhythmia database. Thus, we aim to review validation methods of various R-peak detection methodologies before their implementation in real time. This review discusses the impact of non-beat annotations when using a custom validation method, allowable window tolerance, the effects of window size deviations, and implications of varying numbers of beats and skipping segments on ECG testing, providing a comprehensive guide for researchers. Addressing these validation gaps is critical as they can significantly affect validatory outcomes. Finally, the conclusion section proposes a structured concept as a future approach, a guide to integrate WFDB R-peak validation tools for testing any QRS annotated ECG database. Overall, this review underscores the importance of complete transparency in reporting testing procedures, which prevents misleading assessments of R-peak detection algorithms and enables fair methodological comparison. [ABSTRACT FROM AUTHOR]

This paper introduces a novel deep learning model for ECG signal classification using feature fusion. The proposed methodology transforms the ECG time series into a spectrogram image using a short-time Fourier transform (STFT). This spectrogram is further processed to generate a histogram of oriented gradients (HOG) and local binary pattern (LBP) features. Three separate 2D convolutional neural networks (CNNs) then analyze these three image representations in parallel. To enhance performance, the extracted features are concatenated before feeding them into a gated recurrent unit (GRU) model. The proposed approach is extensively evaluated on two ECG datasets (MIT-BIH + BIDMC and MIT-BIH) with three and five classes, respectively. The experimental results demonstrate that the proposed approach achieves superior classification accuracy compared to existing algorithms in the literature. This suggests that the model has the potential to be a valuable tool for accurate ECG signal classification, aiding in the diagnosis and treatment of various cardiovascular disorders. [ABSTRACT FROM AUTHOR]

Background: Approximately half of all women develop palpitations during pregnancy, with a quarter experiencing arrhythmias. While most presentations are benign, some cases can result in sudden cardiac death or serious symptom development. Considering such clinical presentation, healthcare providers must acquire knowledge in this area to provide comprehensive prenatal, perinatal, and postnatal care. However, no study could be located that focused on women's life experiences of such complications during or in the post-pregnancy period. Objectives: The study aims to share the results of a study that explored the life experience of one woman who developed non-sustained ventricular tachycardia during her third pregnancy that lasted into the postpartum period. Methods: Using narrative inquiry self-study methodology, a woman's experiences were explored to uncover the challenges she faced in coping with such complications during a period of transition for herself and her family. This methodology allowed for an in-depth understanding of how these complications could affect all aspects of her life. Results: Four narrative threads were produced: (1) diagnostic challenges and delayed recognition; (2) impact on maternal identity and family dynamics; (3) navigating healthcare systems and treatment decisions; and (4) long-term adaptation and resilience. Conclusions: The intention was to add to this topic area to ensure future researchers, current and future healthcare providers, and patients have literature they can refer to when studying, providing care for, or experiencing similar health complications. Acquiring this knowledge can aid healthcare professionals to ensure appropriate care is provided, risks are minimized, and their recovery is well supported. [ABSTRACT FROM AUTHOR]

Background: Antiarrhythmic therapy for recurrent ventricular arrhythmias (VAs) in patients having undergone catheter ablation and in whom amiodarone and/or beta-blockers were ineffective or contraindicated is a controversial issue. Purpose: The present study sought to compare the efficacy and tolerability of oral procainamide and mexiletine in patients with recurrent ventricular arrhythmias when the standard therapy strategy failed. Methods: All patients with an implantable cardioverter defibrillator (ICD) treated with oral procainamide or mexiletine for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in two cardiology divisions between January 2010 and January 2020 were enrolled. Patients were divided into group A (oral procainamide) and group B (mexiletine) and the two groups were compared to each other. The primary endpoint was the efficacy of therapy; the secondary endpoint was the discontinuation of therapy. All events that occurred during procainamide or mexiletine treatment were compared with a matched duration period before the initiation of the therapy. Antiarrhythmic therapy was considered effective when a ≥80% reduction of the sustained ventricular arrhythmias burden recorded by the ICD was achieved. Results: A total of 68 consecutive patients (61 males, 89.7%; mean age 74 ± 10 years) were included in this retrospective analysis. After a median follow-up of 19 months, 38 (56%) patients had a significant reduction in the VA burden. After multivariable adjustment, therapy with procainamide was independently associated with an almost 3-fold higher efficacy on VA suppression compared to mexiletine (HR 2.54, 95% CI 1.06–6.14, p = 0.03). Only three patients (9%) treated with procainamide presented severe side effects (dyspnea or hypotension) requiring discontinuation of therapy compared with six patients (18%) treated with mexiletine who interrupted therapy because of severe side effects (p = 0.47). Conclusions: Compared to mexiletine, oral procainamide had a higher efficacy for the treatment of recurrent and refractory VAs, and showed a good profile of tolerability. [ABSTRACT FROM AUTHOR]

Intermittent hypoxia (IH) has been extensively studied in recent years, demonstrating adverse and beneficial effects on several physiological systems. However, the precise mechanism underlying its cardiac effects on the heart remains unclear. This study aims to explore the effect of treatment on atrial fibrillation under IH conditions, providing data that can potentially be used in the treatment of heart disease. An atrial fibrillation (AF) model was induced by injecting monocrotaline (MCT, 60 mg/kg) into rats. The study included 32 rats divided into four groups: Control, Control + IH, AF, and AF + IH. We evaluated molecular changes associated with AF using ELISA and Western blot and performed electrophysiological experiments to evaluate AF. Arrhythmia-related calcium and fibrosis markers were investigated. Phosphorylation levels of CaMKII, Phospholamban, and RyR2 all increased in the AF group but decreased in the IH-exposed group. Additionally, fibrosis marker expressions such as SMA, MMP2, MMP9, and TGF-β increased in the AF group but were significantly downregulated with IH treatment. Connexin 43 and AQP4 expression were restored in the IH-treated group. These findings suggest that IH may prevent AF by downregulating the expression of calcium-handling proteins and fibrosis-associated proteins in an AF-induced rat model. [ABSTRACT FROM AUTHOR]

Arrhythmia is the main cause of sudden cardiac death, and ECG signal analysis is a common method for the noninvasive diagnosis of arrhythmia. In this paper, we propose an arrhythmia classification model based on the combination of a channel attention mechanism (SE module), convolutional neural network (CNN), and long short-term memory neural network (LSTM). The data of this model use the MIT-BIH arrhythmia database, and after noise reduction of raw ECG data by the EEMD denoising algorithm, a CNN-LSTM is used to learn features from the data, and the fusion channel attention mechanism is used to adjust the weight of the feature map. The CNN-LSTM-SE model is compared with the LSTM, CNN-LSTM, and LSTM-attention models, and the models are evaluated using Precision, Recall, and F1-Score. The classification performance of the tested CNN-LSTM-SE classification prediction model is better, with a classification accuracy of 98.5%, a classification precision rate of more than 97% for each label, a recall rate of more than 98%, and an F1-score of more than 0.98. It meets the requirements of arrhythmia classification prediction and has a certain practical value. [ABSTRACT FROM AUTHOR]

Na+-K+ ATPase is an integral component of cardiac sarcolemma and consists of three major subunits, namely the α-subunit with three isoforms (α1, α2, and α3), β-subunit with two isoforms (β1 and β2) and γ-subunit (phospholemman). This enzyme has been demonstrated to transport three Na and two K ions to generate a trans-membrane gradient, maintain cation homeostasis in cardiomyocytes and participate in regulating contractile force development. Na+-K+ ATPase serves as a receptor for both exogenous and endogenous cardiotonic glycosides and steroids, and a signal transducer for modifying myocardial metabolism as well as cellular survival and death. In addition, Na+-K+ ATPase is regulated by different hormones through the phosphorylation/dephosphorylation of phospholemman, which is tightly bound to this enzyme. The activity of Na+-K+ ATPase has been reported to be increased, unaltered and depressed in failing hearts depending upon the type and stage of heart failure as well as the association/disassociation of phospholemman and binding with endogenous cardiotonic steroids, namely endogenous ouabain and marinobufagenin. Increased Na+-K+ ATPase activity in association with a depressed level of intracellular Na+ in failing hearts is considered to decrease intracellular Ca2+ and serve as an adaptive mechanism for maintaining cardiac function. The slight to moderate depression of Na+-K+ ATPase by cardiac glycosides in association with an increased level of Na+ in cardiomyocytes is known to produce beneficial effects in failing hearts. On the other hand, markedly reduced Na+-K+ ATPase activity associated with an increased level of intracellular Na+ in failing hearts has been demonstrated to result in an intracellular Ca2+ overload, the occurrence of cardiac arrhythmias and depression in cardiac function during the development of heart failure. Furthermore, the status of Na+-K+ ATPase activity in heart failure is determined by changes in isoform subunits of the enzyme, the development of oxidative stress, intracellular Ca2+-overload, protease activation, the activity of inflammatory cytokines and sarcolemmal lipid composition. Evidence has been presented to show that marked alterations in myocardial cations cannot be explained exclusively on the basis of sarcolemma alterations, as other Ca2+ channels, cation transporters and exchangers may be involved in this event. A marked reduction in Na+-K+ ATPase activity due to a shift in its isoform subunits in association with intracellular Ca2+-overload, cardiac energy depletion, increased membrane permeability, Ca2+-handling abnormalities and damage to myocardial ultrastructure appear to be involved in the progression of heart failure. [ABSTRACT FROM AUTHOR]

Simple Summary: Myxomatous mitral valve disease (MMVD) is the most common cardiac disease in dogs. It affects the mitral valve apparatus and progresses slowly with age. In some breeds, especially small dogs, i.e., Cavalier King Charles Spaniels, the disease seems to progress faster than in others. According to the guidelines published by the American College of Veterinary Internal Medicine, canine MMVD can be categorized into four stages. Dogs that are affected by MMVD but have not developed clinical signs of heart failure belong to stage B. This stage is further divided into stages B1 and B2, based on the dimensions of the left-sided cardiac chambers. Specifically, stage B1 is assigned if the dimensions of the left-sided cardiac chambers are not remodeled enough to require medical treatment. When they become enlarged enough to need therapy, the disease progresses to stage B2. Although previous studies have investigated electrocardiographic abnormalities and disturbances in autonomic balance in canine MMVD, information in that regard is still limited, especially in the preclinical stages of the disease. Therefore, the present study investigated whether an increase in the dimensions of the left-sided cardiac chambers in dogs with preclinical MMVD (stage B2) would predispose them to cardiac arrhythmias and/or autonomic imbalances. A comparison of electrocardiographic findings from stage B1 and stage B2 dogs showed no statistically significant predisposition to arrhythmias in subjects with enlarged left-sided cardiac chambers. Moreover, the autonomic balance remains adequate in stage B2, as well as in stage B1. Myxomatous mitral valve disease (MMVD) is the most prevalent cardiac disease in dogs. This study aimed to compare the arrhythmogenic profile and heart rate variability (HRV) of dogs with MMVD in stages B1 and B2. Electrocardiographic exams and the medical records of 60 dogs were analyzed, and HRV, P wave dispersion, QT interval dispersion, and QT interval instability parameters were determined. The results showed significantly increased values in stage B2 compared with stage B1 (p < 0.05) regarding P wave maximum and minimum duration (Pmax and Pmin) and short-term instability (STI). In contrast, no statistically significant differences were observed regarding HRV parameters, P wave dispersion, or QT interval dispersion. Our findings showed that cardiac remodeling in stage B2 could not significantly alter the sympathovagal balance and showed little interference with the predisposition of arrhythmias in dogs with MMVD. [ABSTRACT FROM AUTHOR]

Background/Objectives: Risk assessment in pediatric myocarditis is challenging, particularly when left ventricular ejection fraction (LVEF) is preserved. This study aimed to evaluate LV myocardial deformation using speckle-tracking echocardiography (STE)-derived longitudinal +strain (LS) and assessed its diagnostic and prognostic value in children with myocarditis. Methods: Retrospective STE-derived layer-specific LV LS analysis was performed on echocardiograms from patients within the multicenter, prospective registry for pediatric myocarditis "MYKKE". Age- and sex-adjusted logistic regression and ROC analysis identified predictors of cardiac arrhythmias (ventricular tachycardia, ventricular fibrillation, atrioventricular blockage III°) and major adverse cardiac events (MACE: need for mechanical circulatory support (MCS), cardiac transplantation, and/or cardiac death). Results: Echocardiograms from 175 patients (median age 15 years, IQR 7.9–16.5 years; 70% male) across 13 centers were included. Cardiac arrhythmias occurred in 36 patients (21%), and MACE in 28 patients (16%). Impaired LV LS strongly correlated with reduced LVEF (r > 0.8). Impaired layer-specific LV LS, reduced LVEF, LV dilatation, and increased BSA-indexed LV mass, were associated with the occurrence of MACE and cardiac arrhythmias. In patients with preserved LVEF, LV LS alone predicted cardiac arrhythmias (p < 0.001), with optimal cutoff values of −18.0% for endocardial LV LS (sensitivity 0.69, specificity 0.94) and –17.0% for midmyocardial LV LS (sensitivity 0.81, specificity 0.75). Conclusions: In pediatric myocarditis, STE-derived LV LS is not only a valuable tool for assessing systolic myocardial dysfunction and predicting MACE but also identifies patients at risk for cardiac arrhythmias, even in the context of preserved LVEF. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF), the most common arrhythmia, is associated with increased morbidity, mortality, and healthcare costs. Evidence indicates that rhythm control offers superior cardiovascular outcomes compared to rate control, especially when initiated early after the diagnosis of AF. Catheter ablation remains the single best therapy for AF; however, it is not free from severe complications and only a small percentage of AF patients in the Western world ultimately receive ablation. Ensuring that AF ablation is safe, effective, and efficient is essential to make it accessible to all patients. With the limitations of traditional thermal ablative energies, pulsed field ablation (PFA) has emerged as a novel non-thermal energy source. PFA targets irreversible electroporation of cardiomyocytes to achieve cell death without damaging adjacent structures. Through its capability to create rapid, selective lesions in myocytes, PFA presents a promising alternative, offering enhanced safety, reduced procedural times, and comparable, if not superior, efficacy to thermal energies. The surge of new evidence makes it challenging to stay updated and understand the possibilities and challenges of PFA. This review aims to summarize the most significant advantages of PFA and how this has translated to the clinical arena, where four different catheters have received CE-market approval for AF ablation. Further research is needed to explore whether adding new ablation targets, previously avoided due to risks associated with thermal energies, to pulmonary vein isolation can improve the efficacy of AF ablation. It also remains to see whether a class effect exists or if different PFA technologies can yield distinct clinical outcomes given that the optimization of PFA parameters has largely been empirical. [ABSTRACT FROM AUTHOR]

Background. Left ventricular hypertrabeculation (LVHT) is a myocardial disorder with different clinical manifestations, from total absence of symptoms to heart failure, arrhythmias, sudden cardiac death (SCD), and thromboembolic events. It is challenging to distinguish between the benign and pathological forms of LVHT. The aim of this study was to describe the arrhythmic manifestations of LVHT in a large group of pediatric patients and to correlate them with genetic results or other clinical markers. Methods. We retrospectively enrolled 140 pediatric patients with diagnosis of LVHT followed at our Institution from 2013 to 2023. Data regarding family history, instrumental exams, cardiac magnetic resonance, genetic testing and outcomes were collected. Most of them had isolated LVHT (80.7%); in other patients, mixed phenotypes (hypertrophic or dilated cardiomyopathy or congenital heart disease) were present. Results. Arrhythmias were found in 33 children (23.6%): 13 (9.3%) supraventricular tachyarrhythmias; 14 (10%) ventricular arrhythmias (five frequent PVCs (premature ventricular contractions), eight patients with ventricular tachycardia (VT), one ventricular fibrillation (VF)); two (1.4%) sinus node disfunctions; two (1.4%) complete atrio-ventricular blocks (AVB), three (2.1%) paroxysmal complete AVB, one (0.7%) severe I degree AVB. Three patients received an ICD (implantable cardioverter defibrillator). Comparison between LVHT patients with (33 pts) and without (107 pts) arrhythmias as regards genetic testing showed a statistical significance for the presence of class 4 or 5 genetic variants and arrhythmic manifestation (p = 0.037). Conclusions. In our pediatric cohort with LVHT, good outcomes were observed, but arrhythmias were not so rare (23.6%); no SCD occurred. [ABSTRACT FROM AUTHOR]

It is documented that maternal diseases or treatments influence a newborn's clinical status at birth. If a prenatal medical history is not available, or if signs or symptoms of a mother's disease are revealed for the first time during pregnancy or postpartum, their effects on the newborn may be misattributed. Objective: The objective of this study is to emphasize the paramount importance of prenatal care, for both mothers and newborns, as a lack of maternal signs and symptoms during pregnancy does not exclude a potential severe neonatal condition. Materials and methods: We present a series of three cases of pregnant women who gave birth to very sick preterm newborns that required admission to the Neonatal Intensive Care Unit (NICU). The mothers were asymptomatic during pregnancy and unaware of their subclinical disease. The newborns' complications, considered initially as consequences of prematurity or infection, subsequently revealed transient autoimmune disease in two of the cases (myasthenia gravis and hyperthyroidism) and a severe form of thrombophilia in the third case. Results: The newborns' diagnosis preceded maternal diagnosis and contributed to the identification of the maternal pathology; adequate treatment was prescribed, with favorable short- and long-term outcomes. Conclusions: Prenatal exams and investigations throughout pregnancy are a good opportunity to detect subclinical diseases or predispositions. As newborns usually develop non-specific signs, one should have experience and pay attention to differentiating among etiologies. Our paper takes a reversed approach to the usual medical diagnosis pathway: from infant to mother instead of from mother to infant, proving that inter-specialty collaboration can work bi-directionally. [ABSTRACT FROM AUTHOR]

Premature ventricular contractions (PVCs) are a common arrhythmia characterized by ectopic excitations within the ventricles. Accurately estimating the ablation site using an electrocardiogram (ECG) is crucial for the initial classification of PVC origins, typically focusing on the right and left ventricular outflow tracts. However, finer classification, specifically identifying the left cusp (LC), anterior cusp (AC), and right cusp (RC), is essential for detailed preoperative planning. This study aims to improve the accuracy of cardiac waveform source estimation and classification in 27 patients with PVCs originating from the pulmonary valve. We utilized an anatomical human model and electromagnetic simulations to estimate wave source positions from 12-lead ECG data. Time-series source points were identified for each measured ECG waveform, focusing on the moment when the distance between the estimated wave source and the pulmonary valve was minimal. Computational analysis revealed that the distance between the estimated wave source and the pulmonary valve was reduced to less than 1 cm, with LC localization achieving errors under 5 mm. Additionally, 74.1% of the subjects were accurately classified into the correct origin (LC, AC, or RC), with each origin demonstrating the highest percentage of subjects corresponding to the targeted excitation origin. Our findings underscore the novel potential of this source localization method as a valuable complement to traditional waveform classification, offering enhanced diagnostic precision and improved preoperative planning for PVC ablation procedures. [ABSTRACT FROM AUTHOR]

Electrophysiological aspects of cardiac amyloidosis (CA) are still poorly explored compared to other aspects of the disease. However, electrocardiogram (ECG) abnormalities play an important role in CA diagnosis and prognosis and the management of arrhythmias is a crucial part of CA treatment. Low voltages and a pseudonecrosis pattern with poor R-wave progression in precordial leads are especially common findings. These are useful for CA diagnosis and risk stratification, especially when combined with clinical or echocardiographic findings. Both ventricular and supraventricular arrhythmias are common in CA, especially in transthyretin amyloidosis (ATTR), and their prevalence is related to disease progression. Sustained and non-sustained ventricular tachycardias' prognostic role is still debated, and, to date, there is a lack of specific indications for implantable cardiac defibrillator (ICD). On the other hand, atrial fibrillation (AF) is the most common supraventricular arrhythmia with a prevalence of up to 88% of ATTR patients. Anticoagulation should be considered irrespective of CHADsVA score. Furthermore, even if AF seems to not be an independent prognostic factor in CA, its treatment for symptom control is still crucial. Finally, conduction disturbances and bradyarrhythmias are also common, requiring pacemaker implantation in up to 40% of patients. [ABSTRACT FROM AUTHOR]

Objectives: Arterial hypertension (AH) is one of the major risk factors for cardiovascular diseases. An association between untreated AH and arrhythmia is observed. Cardiac magnetic resonance (CMR) assesses myocardial fibrosis by detecting foci of late gadolinium enhancement (LGE). Clinical significance of LGE at the right ventricular insertion point (RVIP) is not fully established. This study aimed to assess the relationship between the presence of LGE at the RVIP determined by CMR and the incidence of arrhythmia in a group suffering from arterial hypertension. Methods: The study group consisted of 81 patients with AH (37 men and 44 women, age: 56.7 ± 7.1 years). All subjects underwent CMR and 24 h Holter ECG monitoring. Two subgroups were distinguished in the study group based on the criterion of the presence of LGE at the RVIP in CMR. The RVIP+ subgroup consisted of patients with LGE at the RVIP, while the RVIP− group consisted of patients without LGE at the RVIP. Results: The RVIP+ subgroup was characterized by higher maximum and minimum heart rates in 24 h Holter ECG recordings compared to the RVIP− subgroup (p < 0.05). The RVIP+ subgroup had a statistically significantly higher number of single premature supraventricular beats, supraventricular tachycardias, and single premature ventricular beats than the RVIP− subgroup (p < 0.05). Regression analysis documented that a longer duration of AH (counted from diagnosis) as well as the occurrence of LGE at the RVIP (assessed by CMR) are independent risk factors for arrhythmia (p < 0.05). Conclusions: Due to the possibility of detecting LGE at the RVIP, CMR may be a useful diagnostic method in estimating the risk of arrhythmias in the group of patients with AH. [ABSTRACT FROM AUTHOR]

Ventricular tachycardia poses a significant therapeutic challenge. It can manifest over a spectrum from minimal palpitation symptoms to sudden cardiac death. This makes large-scale trials on the treatment of ventricular tachycardia difficult to perform. The mechanism of ventricular tachycardia must also be understood before embarking on treatment. Patients with or without structural heart disease will have different mechanisms for the onset and propagation of these arrhythmias. Catheter ablation is an established management option for ventricular tachycardia; however, it is not always successful and anti-arrhythmic medications are often necessary to control these life-threatening arrhythmias. Although anti-arrhythmics can suppress ventricular tachycardias they also carry side effects. In certain substrates, some of these medications can exacerbate arrhythmias or heart failure. For these reasons, a multifaceted approach to treating ventricular tachycardia is necessary. This paper is a comprehensive review of the comprehensive management strategies for ventricular tachycardia. Anti-arrhythmic medications have an important role and their use in various cardiomyopathies and channelopathies is reviewed in detail. We also review the promising effects of gene therapy and artificial intelligence on different substrates for ventricular tachycardia. [ABSTRACT FROM AUTHOR]

Echocardiography is recommended as a first-line diagnostic tool in patients with premature ventricular contractions (PVCs). However, standard echocardiography is not always able to identify early signs of myocardial dysfunction and cardiac magnetic resonance (CMR) may offer additional information. Since CMR has lower accessibility and higher cost compared to echocardiography, we wanted to evaluate how additional echocardiographic parameters, not included in routine examinations, perform compared to CMR in detecting signs of cardiomyopathy in PVC patients with normal findings at a standard echocardiogram. We compared CMR findings and results from an extended echocardiographic examination in thirty-nine patients who had a high PVC burden. The additional echocardiographic parameters were global longitudinal strain, mechanical dispersion, ventricular–arterial coupling, integrated backscatter and left atrial activation time. Eleven patients had pathological findings at CMR. The additional echocardiographic parameters did not significantly differ between patients with or without CMR findings. However, several patients with normal CMR findings showed signs of ventricular dysfunction when evaluated with the additional echocardiographic parameters, which suggests that these could possibly offer supplementary information in the assessment of PVC patients. [ABSTRACT FROM AUTHOR]

Background: There are many types of arrhythmias which may threaten health that are well-known or opaque. The purpose of this pilot study was to examine how different cardiac health risk factors rank together in association with arrhythmias in young, middle-aged, and older adults. Methods: The analytic sample included 101 adults aged 50.6 ± 22.6 years. Several prominent heart-health-related risk factors were self-reported. Mean arterial pressure and body mass index were collected using standard procedures. Hydraulic handgrip dynamometry measured strength capacity. A 6 min single-lead electrocardiogram evaluated arrhythmias. Respiratory sinus arrhythmias (RSAs) and ectopic heart beats were observed and specified for analyses. Classification and Regression Tree analyses were employed. Results: A mean arterial pressure ≥ 104 mmHg was the first level predictor for ectopic beats, while age ≥ 41 years was the first level predictor for RSAs. Age, heart rate, stress and anxiety, and physical activity emerged as important variables for ectopic beats (p < 0.05), whereas age, sodium, heart rate, and gender were important for RSAs (p < 0.05). Conclusions: RSAs and ectopic arrhythmias may have unique modifiable and non-modifiable factors that may help in understanding their etiology for prevention and treatment as appropriate across the lifespan. [ABSTRACT FROM AUTHOR]

Hypokalemic paralysis is a clinical syndrome characterized by acute flaccid paralysis with concomitant hypokalemia. Complications, such as acute respiratory failure and cardiac arrhythmias, can be fatal. If treated appropriately, the patient can recover without any sequelae. We present a rare case of life-threatening hypokalemic paralysis following the ingestion of an unknown substance. At presentation, her serum potassium concentration was 1.9 mmol/L. A review of the patient's history confirmed the ingestion of barium chloride. She was diagnosed with acute barium poisoning characterized by high serum and urine barium levels. Aggressive potassium repletion was administered intravenously and orally. Her serum potassium concentration dropped to 1.5 mmol/L and peaked at 5.4 mmol/L following treatment. The patient achieved a complete recovery and was discharged without sequelae. Barium can competitively block the potassium inward rectifier channels and interfere with the efflux of intracellular potassium, leading to severe hypokalemia. Our report illustrates a rare presentation of acute barium intoxication and a differential diagnosis indicating hypokalemic paralysis. We also discuss the pathophysiological features and compare the clinical findings with cases of rebound hyperkalemia. [ABSTRACT FROM AUTHOR]

Objectives: this study aims to evaluate the prevalence of various arrhythmias and other electrocardiographic patterns within the group of individuals with overweight and obesity. Methods: One hundred eighty-one adults (90 females and 91 males) were qualified for inclusion in the experimental group. All participants had a body mass index (BMI) exceeding 25 kg/m2 (98 patients with obesity and 83 with overweight). The mean BMI in the obesity group was 33.6 kg/m2, and all participants had class 1 obesity. The control group comprised 69 individuals (56 females and 13 males) with normal BMI. The basic measurements were performed, and the participants filled out questionnaires describing their health conditions and lifestyles. Each participant underwent an electrocardiographic (ECG) examination and a 24 h Holter ECG examination. Results: In patients with class 1 obesity compared to the control patients, the average numbers of premature ventricular beats (PVBs) and premature supraventricular beats (SPBs) were statistically significantly higher (p = 0.030 and p = 0.042). There was a positive correlation between body weight and PVB (p = 0.028) and between body weight and SPB (p = 0.028). Moreover, BMI and waist circumference were correlated with SPB (p = 0.043 and p = 0.031). In the backward stepwise multivariate regression model considering 24 h Holter ECG monitoring, concerning SPB as the dependent variable, it was observed that BMI (especially obesity class 1), type 2 diabetes, and thyroid disease exhibited the highest regression coefficients. Conclusions: obesity, even in class 1, might be a factor in a more frequent occurrence of abnormalities in electrocardiographic tests. [ABSTRACT FROM AUTHOR]

The emergence of gene therapy offers opportunities for treating a myriad of genetic disorders and complex diseases that previously had limited or no treatment options. The key basic strategies for gene therapy involve either the addition, inhibition, or introduction of a new gene, with a crucial component being the use of a delivery vector to effectively target cells. Particularly promising is the application of gene therapy for the treatment of inherited arrhythmia syndromes, conditions associated with significant mortality and morbidity that have limited treatment options, and a paucity of disease modifying therapy. This review aims to summarize the utility of gene therapy for the treatment of inherited arrhythmia syndromes by exploring the current state of knowledge, limitations, and future directions. [ABSTRACT FROM AUTHOR]

(1) Background: The aim of this review was to identify and summarize adverse cardiovascular health events associated with the simultaneous consumption of energy drinks (ED) and alcohol. Potential prevention strategies and the implementation of research toward the underlying mechanisms for these pathologies were highlighted to emphasize the need for further investigation and to encourage more attention to this field. (2) Methods: The PubMed database was searched for case reports linked with adverse cardiovascular events after simultaneous ED and alcohol consumption. Inclusion criteria were: the reported age of the patient is between 16 and 35 years and confirmed co-consumption of EDs and alcohol. All relevant articles that met the inclusion criteria were fully read and all relevant data was extracted. The extracted data was summarized and presented in this review of cases. (3) Results: In total, 10 cases were identified. The analysis showed that mainly young adults (median age = 24.5 years), in particular men (80%) were affected. The three parts of the cardiovascular system affected were heart rhythm (42%), myocardial function (33%), and coronary arteries (25%). In 3 cases the outcome was fatal. Moreover, preexisting health conditions and/or potential trigger factors were present in 60% of selected cases. (4) Conclusions: This review of case reports suggests that the simultaneous consumption of EDs and alcohol can lead to adverse cardiovascular health events and even incidents with fatal outcomes were reported. Potential trigger factors and preexisting health conditions seem to increase the probability of adverse cardiovascular health events. Consumers should be informed about the potential risks and follow responsible consumption behavior to prevent future health events. More systematic studies are needed to determine the acute effects on the cardiovascular system in young adults. [ABSTRACT FROM AUTHOR]

Recent epidemiological studies have shown that patients with right-sided breast cancer (RBC) treated with X-ray irradiation (IR) are more susceptible to developing cardiovascular diseases, such as arrhythmias, atrial fibrillation, and conduction disturbances after radiotherapy (RT). Our aim was to investigate the mechanisms induced by low to moderate doses of IR and to evaluate changes in the cardiac sympathetic nervous system (CSNS), atrial remodeling, and calcium homeostasis involved in cardiac rhythm. To mimic the RT of the RBC, female C57Bl/6J mice were exposed to X-ray doses ranging from 0.25 to 2 Gy targeting 40% of the top of the heart. At 60 weeks after RI, Doppler ultrasound showed a significant reduction in myocardial strain, ejection fraction, and atrial function, with a significant accumulation of fibrosis in the epicardial layer and apoptosis at 0.5 mGy. Calcium transient protein expression levels, such as RYR2, NAK, Kir2.1, and SERCA2a, increased in the atrium only at 0.5 Gy and 2 Gy at 24 h, and persisted over time. Interestingly, 3D imaging of the cleaned hearts showed an early reduction of CSNS spines and dendrites in the ventricles and a late reorientation of nerve fibers, combined with a decrease in SEMA3a expression levels. Our results showed that local heart IR from 0.25 Gy induced late cardiac and atrial dysfunction and fibrosis development. After IR, ventricular CSNS and calcium transient protein expression levels were rearranged, which affected cardiac contractility. The results are very promising in terms of identifying pro-arrhythmic mechanisms and preventing arrhythmias during RT treatment in patients with RBC. [ABSTRACT FROM AUTHOR]

Myocardial ischaemia reperfusion injury (IRI) occurring from acute coronary artery disease or cardiac surgical interventions such as bypass surgery can result in myocardial dysfunction, presenting as, myocardial "stunning", arrhythmias, infarction, and adverse cardiac remodelling, and may lead to both a systemic and a localised inflammatory response. This localised cardiac inflammatory response is regulated through the nucleotide-binding oligomerisation domain (NACHT), leucine-rich repeat (LRR)-containing protein family pyrin domain (PYD)-3 (NLRP3) inflammasome, a multimeric structure whose components are present within both cardiomyocytes and in cardiac fibroblasts. The NLRP3 inflammasome is activated via numerous danger signals produced by IRI and is central to the resultant innate immune response. Inhibition of this inherent inflammatory response has been shown to protect the myocardium and stop the occurrence of the systemic inflammatory response syndrome following the re-establishment of cardiac circulation. Therapies to prevent NLRP3 inflammasome formation in the clinic are currently lacking, and therefore, new pharmacotherapies are required. This review will highlight the role of the NLRP3 inflammasome within the myocardium during IRI and will examine the therapeutic value of inflammasome inhibition with particular attention to carbon monoxide, nitric oxide, and hydrogen sulphide as potential pharmacological inhibitors of NLRP3 inflammasome activation. [ABSTRACT FROM AUTHOR]

This review examines the relationship between the physiological demands of diving and premature ventricular complexes (PVCs) in divers. In the general population, some individuals have a greater tendency to experience PVCs, often without awareness or a clear understanding of the triggering factors. With the increasing availability and popularity of both scuba and apnoea diving, more people, including those with a predisposition to PVCs, are engaging in these activities. The underwater environment, with its unique stressors, may increase the risk of arrhythmogenic events, particularly PVCs. Here, we review the prevalence, pathophysiology, and aggravating factors of PVCs in divers, emphasising the need for a comprehensive cardiovascular assessment. Evidence suggests a higher prevalence of PVCs in divers compared with the general population, influenced by factors such as age, dive depth, gas bubbles, cold water immersion, pre-existing cardiovascular diseases, and lifestyle factors. The change in environment during diving could potentially trigger an increased frequency of PVCs, especially in individuals with a pre-existing tendency. We discuss diagnostic strategies, management approaches, and preventive measures for divers with PVCs, noting that although guidelines for athletes can be adapted, individual assessment is crucial. Significant knowledge gaps are identified, highlighting the need for future research to develop evidence-based guidelines and understand the long-term significance of PVCs in divers. This work aims to evaluate potential contributing factors to PVCs in divers and identify individuals who may be at higher risk of experiencing major adverse cardiovascular events (MACEs). This work aims to improve diver safety by promoting collaboration between cardiologists and diving medicine specialists and by identifying key areas for future investigation in this field. This work aims to improve the safety and well-being of divers by understanding the cardiovascular challenges they face, including pressure changes, cold water immersion, and hypoxia. We seek to elucidate the relationship between these challenges and the occurrence of PVCs. By synthesising current evidence, identifying knowledge gaps, and proposing preliminary recommendations, we aim to encourage collaboration between cardiologists and diving medicine specialists to optimise the screening, management, and risk stratification of PVCs in the diving population. [ABSTRACT FROM AUTHOR]

One of the recent advancements in the field of cardiac electrophysiology is pulsed field ablation (PFA). PFA is a novel energy modality that does not rely on thermal processes to achieve ablation which, in turn, results in limited collateral damage to surrounding structures. In this review, we discuss the mechanisms, safety, efficacy, and clinical applications of PFA for the management of atrial and ventricular arrhythmias. We also summarize the published pre-clinical and clinical studies regarding this new technology. [ABSTRACT FROM AUTHOR]

Background/Objectives: Most data on radiofrequency (RF) effects come from ex vivo or in vitro studies that quantify lesions using width and/or depth, while electrophysiologists use manufacturers' indirect indices. The objective of this study was to evaluate RF lesion volume by high-resolution MRI of excised lesions in an in vivo porcine model, comparing a low-energy long-duration (LE) (20 W, 50 s) RF application strategy with a high-energy short-duration (HE) (50 W, 20 s) one. Methods: Eighteen piglets were divided into LE (n = 9) and HE groups (n = 9). RF applications were performed at four locations in both atria. Animals were sacrificed after 5–7 days, and RF lesion specimens were excised, fixed, and analyzed by 9.4 Tesla MRI. RF lesion volume, variability (variance), depth, and any extracardiac lesions were compared between the groups. Results: Seventy RF applications were performed (36 LE, 34 HE). MRI analyzed 26 LE and 28 HE samples. The HE group showed 35% higher volume than the LE group (100.2 mm3 (±81.2) in LE vs. 178.3 mm3 (±163.7) in HE, p = 0.033). RF volume variance was 6.6 mm3 in LE and 40.3 mm3 in HE. The HE group had more complications (seven vs. zero, p = 0.02) and extracardiac lesions (18 vs. 14, p = 0.613). Conclusions: There was large and unpredictable variability in RF injury on the atrial wall, even under controlled conditions, which could explain arrhythmia recurrences. The greatest lesion variability was found during HE applications. The dose/effect relationship of RF needs careful study for treating cardiac arrhythmias. [ABSTRACT FROM AUTHOR]

Background/Objectives: Limited data are available regarding the prognostic impact of premature ventricular complex (PVC) burden in patients with atrial fibrillation (AF). We sought to compare clinical outcomes in patients with AF according to PVC burden via 24 h Holter monitoring. Methods: From January 2010 to December 2020, 4834 oral anticoagulant (OAC)-naïve non-valvular AF (NVAF) patients who underwent 24 h Holter monitoring were included for analysis. Results: Among the 4834 OAC-naïve NVAF patients, 2835 patients (58.6%) exhibited at least one PVC within a 24 h monitoring period, and 120 patients (2.5%) displayed a daily PVC burden exceeding 10%. In the follow-up echocardiography, patients with a daily PVC burden of ≥10% exhibited lower left ventricular ejection fraction, larger left atrial volume, and higher right ventricular systolic pressure and E/e' than those with a daily PVC burden of <10%. The risk of ischemic stroke (adjusted HR 2.332, p = 0.015) and heart failure admission (adjusted HR 2.147, p = 0.010) were significantly higher in the patients with a daily PVC burden of ≥10% than in those with a daily PVC burden of <10%. However, the incidence of cardiac death was not significantly different between the two groups. A daily PVC burden of ≥10% was independently associated with the risk of ischemic stroke in the OAC-naïve NVAF patients, irrespective of the CHA2DS2–VASc score, AF type, and left atrial size. Conclusions: The current results suggest that evaluating and monitoring the burden of PVCs in patients with NVAF is an important aspect of predicting stroke and heart failure admission. [ABSTRACT FROM AUTHOR]

Ranolazine is an anti-anginal medication that has demonstrated antiarrhythmic properties by inhibiting both late sodium and potassium currents. Studies have shown promising results for ranolazine in treating both atrial fibrillation and ventricular arrhythmias, particularly when used in combination with other medications. This review explores ranolazine's mechanisms of action and its potential role in cardiac arrhythmias treatment in light of previous clinical studies. [ABSTRACT FROM AUTHOR]

Electrocardiography (ECG) plays a pivotal role in monitoring cardiac health, yet the manual analysis of ECG signals is challenging due to the complex task of identifying and categorizing various waveforms and morphologies within the data. Additionally, ECG datasets often suffer from a significant class imbalance issue, which can lead to inaccuracies in detecting minority class samples. To address these challenges and enhance the effectiveness and efficiency of cardiac arrhythmia detection from imbalanced ECG datasets, this study proposes a novel approach. This research leverages the MIT-BIH arrhythmia dataset, encompassing a total of 109,446 ECG beats distributed across five classes following the Association for the Advancement of Medical Instrumentation (AAMI) standard. Given the dataset's inherent class imbalance, a 1D generative adversarial network (GAN) model is introduced, incorporating the Bi-LSTM model to synthetically generate the two minority signal classes, which represent a mere 0.73% fusion (F) and 2.54% supraventricular (S) of the data. The generated signals are rigorously evaluated for similarity to real ECG data using three key metrics: mean squared error (MSE), structural similarity index (SSIM), and Pearson correlation coefficient (r). In addition to addressing data imbalance, the work presents three deep learning models tailored for ECG classification: SkipCNN (a convolutional neural network with skip connections), SkipCNN+LSTM, and SkipCNN+LSTM+Attention mechanisms. To further enhance efficiency and accuracy, the test dataset is rigorously assessed using an ensemble model, which consistently outperforms the individual models. The performance evaluation employs standard metrics such as precision, recall, and F1-score, along with their average, macro average, and weighted average counterparts. Notably, the SkipCNN+LSTM model emerges as the most promising, achieving remarkable precision, recall, and F1-scores of 99.3%, which were further elevated to an impressive 99.60% through ensemble techniques. Consequently, with this innovative combination of data balancing techniques, the GAN-SkipNet model not only resolves the challenges posed by imbalanced data but also provides a robust and reliable solution for cardiac arrhythmia detection. This model stands poised for clinical applications, offering the potential to be deployed in hospitals for real-time cardiac arrhythmia detection, thereby benefiting patients and healthcare practitioners alike. [ABSTRACT FROM AUTHOR]

Simple Summary: Cardiac fibrosis is a common manifestation of heart disease that leads to the deterioration of cardiac function and the development of cardiac arrhythmias. Atrial fibrillation (AF) is particularly influenced by cardiac fibrosis, which is considered one of the primary factors in its development. Various diagnostic techniques can be employed to assess myocardial fibrosis, including cardiac imaging and the evaluation of circulating biomarkers. Among these biomarkers, galectin-3 (Gal-3) is notable for its involvement in inflammation and tissue fibrosis associated with cardiac disease. In humans, several studies have reported that an increased serum Gal-3 concentration is a risk factor for AF. In this study, we evaluated the serum concentration of Gal-3 in 26 dogs with AF associated with acquired cardiac diseases. A total of 17 cardiac healthy dogs and 30 dogs with cardiac disease but without AF served as controls. Our findings indicated no significant difference in Gal-3 concentrations between healthy dogs and dogs with cardiac disease, regardless of the presence of AF. Gal-3 showed a significant positive correlation with age. The results of this study suggest that Gal-3 does not have an important role for the development of AF in dogs, but it is associated with advanced age. Galectin-3 (Gal-3) is a lectin associated with fibrosis and inflammation, and increased circulating concentrations are considered a risk factor for atrial fibrillation (AF) in humans. This retrospective study aimed to evaluate the serum concentration of Gal-3 in dogs with cardiac disease, both with and without AF. Dogs with AF associated with acquired heart diseases were selected, while cardiac healthy dogs and dogs with heart diseases but without AF served as controls. We statistically compared the serum concentration of Gal-3, which was assessed using a commercial canine-specific ELISA kit, among healthy dogs and dogs with heart disease with and without AF. Additionally, associations between Gal-3 and clinical and echocardiographic variables were evaluated. A total of 73 dogs were included, of which 17/73 (23.3%) were cardiac healthy and 56/73 (76.7%) had heart disease, with 26/56 (46.4%) having AF. No significant difference in Gal-3 concentration was found between cardiac healthy dogs (3.90 ± 1.65 ng/mL) and dogs with heart disease, either with or without AF (3.37 ± 1.04 ng/mL, p = 0.436 and 4.68 ± 1.80 ng/mL, p = 0.332, respectively). Gal-3 showed a significant positive correlation with age (r = 0.47, p < 0.001) and a negative correlation with body weight (r = −0.45, p < 0.001). The results of this study suggest that Gal-3 does not have an important role in the development of AF in dogs, but it is associated with advanced age. [ABSTRACT FROM AUTHOR]

Many patients with a hematologic malignancy have other pre-existing conditions at the time of consideration of an allogeneic stem cell transplant (allo-HSCT). Among these, mild-to-moderate chronic kidney disease (CKD) is a common comorbid condition that can potentially impact the rates of non-relapse mortality among transplant patients. While the risk of severe CKD on allo-HSCT is well recognized, there remains a paucity of data in terms of the impact of mild-to-moderate CKD on patient outcomes in this setting. Using data from the National Inpatient Sample database, we aimed to investigate the impact of mild-to-moderate CKD on hospitalization outcomes for patients undergoing an allo-HSCT. Multivariate analysis revealed that CKD patients had a 31% higher risk of all-cause mortality (OR = 1.31, 95% CI: 1.01–1.70; p = 0.04) and a higher risk of other common hospitalization complications, including acute kidney injury, acute pulmonary edema, cardiac arrhythmias, and septic shock. While this study has limitations, including its retrospective nature and lack of specific medication data, it underscores the importance of considering CKD as a significant risk factor in allo-HSCT outcomes. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most prevalent arrhythmia characterized by intermittent and asymptomatic episodes. However, traditional detection methods often fail to capture the sporadic and intricate nature of AF, resulting in an increased risk of false-positive diagnoses. To address these challenges, this study proposes an intelligent AF detection and diagnosis method that integrates Complementary Ensemble Empirical Mode Decomposition, Power-Normalized Cepstral Coefficients, Bi-directional Long Short-term Memory (CEPNCC-BiLSTM), and photoelectric volumetric pulse wave technology to enhance accuracy in detecting AF. Compared to other approaches, the proposed method demonstrates faster preprocessing efficiency and higher sensitivity in detecting AF while effectively filtering out false alarms from photoplethysmography (PPG) recordings of non-AF patients. Considering the limitations of conventional AF detection evaluation systems that lack a comprehensive assessment of efficiency and accuracy, this study proposes the ET-score evaluation system based on F-measurement, which incorporates both computational speed and accuracy to provide a holistic assessment of overall performance. Evaluated with the ET-score, the CEPNCC-BiLSTM method outperforms EEMD-based improved Power-Normalized Cepstral Coefficients and Bi-directional Long Short-term Memory (EPNCC-BiLSTM), Support Vector Machine (SVM), EPNCC-SVM, and CEPNCC-SVM methods. Notably, this approach achieves an outstanding accuracy rate of up to 99.2% while processing PPG recordings within 5 s, highlighting its potential for long-term AF monitoring. [ABSTRACT FROM AUTHOR]

Arrhythmias range from mild nuisances to potentially fatal conditions, detectable through electrocardiograms (ECGs). With advancements in wearable technology, ECGs can now be monitored on-the-go, although these devices often capture noisy data, complicating accurate arrhythmia detection. This study aims to create a new deep learning model that utilizes generative adversarial networks (GANs) for effective noise removal and ResNet for precise arrhythmia classification from wearable ECG data. We developed a deep learning model that cleans ECG measurements from wearable devices and detects arrhythmias using refined data. We pretrained our model using the MIT-BIH Arrhythmia and Noise databases. Least squares GANs were used for noise reduction, maintaining the integrity of the original ECG signal, while a residual network classified the type of arrhythmia. After initial training, we applied transfer learning with actual ECG data. Our noise removal model significantly enhanced data clarity, achieving over 30 dB in a signal-to-noise ratio. The arrhythmia detection model was highly accurate, with an F1-score of 99.10% for noise-free data. The developed model is capable of real-time, accurate arrhythmia detection using wearable ECG devices, allowing for immediate patient notification and facilitating timely medical response. [ABSTRACT FROM AUTHOR]

Exposing cells to intense and brief electric field pulses can modulate cell permeability, a phenomenon termed electroporation. When applied in medical treatments of diseases like cancer and cardiac arrhythmias, depending on level of cellular destruction, it is also referred to as irreversible electroporation (IRE) or Pulsed Field Ablation (PFA). For ablation device testing, several pulse parameters need to be characterized in a comprehensive manner to assess lesion boundary and efficacy. Overly aggressive voltages and application numbers increase animal burden. The potato tuber is a widely used initial model for the early testing of electroporation. The aim of this study is to characterize and refine bench testing for the ablation outcomes of PFA in this simplistic vegetal model. For in vitro assays, several pulse parameters like voltage, duration, and frequency were modulated to study effects not only on 2D ablation area but also 3D depth and volume. As PFA is a relatively new technology with minimal thermal effects, we also measured temperature changes before, during, and after ablation. Data from experiments were supplemented with in silico modeling to examine E-field distribution. We have estimated the irreversible electroporation threshold in Solanum Tuberosum to be at 240 V/cm. This bench testing platform can screen several pulse recipes at early stages of PFA device development in a rapid and high-throughput manner before proceeding to laborious trials for IRE medical devices. [ABSTRACT FROM AUTHOR]

In polymicrobial sepsis, the extracellular histones, mainly released from activated neutrophils, significantly contribute to cardiac dysfunction (septic cardiomyopathy), as demonstrated in our previous studies using Echo-Doppler measurements. This study aims to elucidate the roles of extracellular histones and their interactions with Toll-like receptors (TLRs) in cardiac dysfunction. Through ex vivo assessments of ECG, left ventricle (LV) function parameters, and in vivo Echo-Doppler studies in mice perfused with extracellular histones, we aim to provide comprehensive insights into the mechanisms underlying sepsis-induced cardiac dysfunction. Langendorff-perfused hearts from both wild-type and TLR2, TLR3, or TLR4 knockout (KO) mice were examined. Paced mouse hearts were perfused with histones to assess contractility and relaxation. Echo-Doppler studies evaluated cardiac dysfunction after intravenous histone injection. Histone perfusion caused defects in contractility and relaxation, with TLR2 and TLR3 KO mice being partially protected. Specifically, TLR2 KO mice exhibited the greatest reduction in Echo-Doppler abnormalities, while TLR4 KO exacerbated cardiac dysfunction. Among individual histones, H1 induced the most pronounced abnormalities in cardiac function, apoptosis of cardiomyocytes, and LDH release. Our data highlight significant interactions between histones and TLRs, providing insights into histones especially H1 as potential therapeutic targets for septic cardiomyopathy. Further studies are needed to explore specific histone–TLR interactions and their mechanisms. [ABSTRACT FROM AUTHOR]

According to the World Health Organization (WHO), cardiovascular illnesses, including arrhythmia, are the primary cause of mortality globally, responsible for over 31% of all fatalities each year. To reduce mortality, early and precise diagnosis is essential. Although the analysis of electrocardiograms (ECGs) is the primary means of detecting arrhythmias, it depends significantly on the expertise and subjectivity of the health professional reading and interpreting the ECG, and errors may occur in detection. Artificial intelligence provides tools, techniques, and models that can support health professionals in detecting arrhythmias. However, these tools are based only on ECG data, of which the process of obtaining is an invasive, high-cost method requiring specialized equipment and personnel. Smartwatches feature sensors that can record real-time signals indicating the heart's behavior, such as ECG signals and heart rate. Using this approach, we propose a machine learning- and deep learning-based approach for detecting arrhythmias using heart rate data obtained with smartwatches. Heart rate data were collected from 252 patients with and without arrhythmias who attended a clinic in Arequipa, Peru. Heart rates were also collected from 25 patients who wore smartwatches. Ten machine learning algorithms were implemented to generate the most effective arrhythmia recognition model, with the decision tree algorithm being the most suitable. The results were analyzed using accuracy, sensitivity, and specificity metrics. Using Holter data yielded values of 93.2%, 91.89%, and 94.59%, respectively. Using smartwatch data yielded values of 70.83%, 91.67%, and 50%, respectively. These results indicate that our model can effectively recognize arrhythmias from heart rate data. The high sensitivity score suggests that our model adequately recognizes true positives; that is, patients with arrhythmia. Likewise, its specificity suggests an adequate recognition of false positives. [ABSTRACT FROM AUTHOR]

Research on computer-aided arrhythmia classification is actively conducted, but the limited generalization capacity constrains its applicability in practical clinical settings. One of the primary challenges in deploying such techniques in real-world scenarios is the inter-patient variability and the consequent performance degradation. In this study, we leverage our previous innovation, the n-beat-score map (n-BSM), to introduce an adversarial framework to mitigate the issue of poor performance in arrhythmia classification within the inter-patient paradigm. The n-BSM is a 2D representation of the ECG signal, capturing its constituent beat characteristics through beat-score vectors derived from a pre-trained beat classifier. We employ adversarial learning to eliminate patient-dependent features during the training of the beat classifier, thereby generating the patient-independent n-BSM (PI-BSM). This approach enables us to concentrate primarily on the learning characteristics associated with beat type rather than patient-specific features. Through a beat classifier pre-trained with adversarial learning, a series of beat-score vectors are generated for the beat segments that make up a given ECG signal. These vectors are then concatenated chronologically to form a PI-BSM. Utilizing PI-BSMs as the input, an arrhythmia classifier is trained to differentiate between distinct types of rhythms. This approach yields a 14.27% enhancement in the F1-score in the MIT-BIH arrhythmia database and a 4.97% improvement in cross-database evaluation using the Chapman–Shaoxing 12-lead ECG database. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most prevalent form of arrhythmia, with a rising incidence and prevalence worldwide, posing significant implications for public health. In this paper, we introduce an approach that combines the Recurrence Plot (RP) technique and the ResNet architecture to predict AF. Our method involves three main steps: using wavelet filtering to remove noise interference; generating RPs through phase space reconstruction; and employing a multi-level chained residual network for AF prediction. To validate our approach, we established a comprehensive database consisting of electrocardiogram (ECG) recordings from 1008 AF patients and 48,292 Non-AF patients, with a total of 2067 and 93,129 ECGs, respectively. The experimental results demonstrated high levels of prediction precision (90.5%), recall (89.1%), F1 score (89.8%), accuracy (93.4%), and AUC (96%) on our dataset. Moreover, when tested on a publicly available AF dataset (AFPDB), our method achieved even higher prediction precision (94.8%), recall (99.4%), F1 score (97.0%), accuracy (97.0%), and AUC (99.7%). These findings suggest that our proposed method can effectively extract subtle information from ECG signals, leading to highly accurate AF predictions. [ABSTRACT FROM AUTHOR]

Arrhythmias are highly prevalent in adults with congenital heart disease. For the clinician caring for this population, an understanding of pathophysiology, diagnosis, and management of arrhythmia is essential. Herein we review the latest updates in diagnostics and treatment of tachyarrhythmias and bradyarrhythmias, all in the context of congenital anatomy, hemodynamics, and standard invasive palliations for congenital heart disease. [ABSTRACT FROM AUTHOR]

Aim: Cardiac arrhythmias are among the most important pathologies that cause sudden death. The exploration of new therapeutic options against arrhythmias with low undesirable effects is of paramount importance. Methods: However, the convenient and typical animal model for screening the potential lead compound becomes a very critical modality, particularly in anti-arrhythmia. In this study, mice were intraperitoneally (i.p.) injected with BaCl2, CaCl2, and adrenaline to induce arrhythmia, and simultaneously compared with BaCl2-induced rats. Results: Electrocardiogram (ECG) showed that the majority of mice repeatedly developed ventricular bigeminy, ventricular tachycardia (VT), and ventricular fibrillation (VF) after BaCl2-injection as seen in rats. The ECG of mice developed ventricular bigeminy and VT after CaCl2 and AT after adrenaline i.p. injection. Additionally, acute cardiac arrhythmia after BaCl2 i.p. injection could be reverted by drugs (lidocaine and amiodarone) administration. Additionally, the different routes of administration for various chemical-induced arrhythmia in both mice and rats were also retrieved from PubMed and summarized. Comparing this approach with previous studies after the literature review reveals that arrhythmia of BaCl2-induced i.p. mice is compatible with the induction of other routes. Conclusions: This study brings an alternative experimental model to investigate antiarrhythmic theories and provides a promising approach to discovering new interventions for acute arrhythmias. [ABSTRACT FROM AUTHOR]

Given the continuous changes in the world, with an increasing trend of unhealthy lifestyles, metabolic comorbidities, and increased susceptibility to cardiovascular diseases (CVDs), researchers change their attention to improve not only the therapeutic platform but also current CVD predictive and prognostic tools to improve disease outcomes. As CVD is characterized by an inflammatory paradigm involving, to some degree, the innate and adaptative immune systems, the neutrophil-to-lymphocyte ratio (NLR) emerged as a potential low-cost, rapidly available, and reliable inflammatory marker, with substantial recent evidence showing its potential utility in clinical practice. Thus, in this literature review, we will present an up-to-date discussion of the prognostic role of NLR in the most frequent CVDs, such as acute and chronic coronary disease, atherosclerotic disease, heart failure, cardiac valvopathies, and cardiac arrhythmias with predilection to atrial fibrillation. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia globally. High-power, short-duration radiofrequency (RF) catheter ablation (CA) for AF has recently emerged, reducing ablation times and enhancing patient tolerability with comparable efficacy and safety. While the benefits of general anesthesia (GA) for standard-power, standard-duration CA are well-established, data comparing GA to mild conscious sedation (MCS) for high-power, short-duration CA are limited. Methods: We included patients undergoing high-power, short-duration CA for AF under GA (group 1) or MCS (group 2). Procedural characteristics, success rates, and mid-term outcomes were compared. Results: In total, 131 patients, 47 in the GA group and 84 in the MCS group, were included. CA was performed for paroxysmal AF in 34 patients in group 1 (72.3%) and 68 patients in group 2 (80.9%). We found lower a mean total procedure time (100 [90–120] vs. 160 [130–180] min, p < 0.0001), lower radiation exposure (932.5 [625–1716] vs. 2445 [1228–4791] μGy, p < 0.0001 and 4.5 [3–7.1] 7.3 [4.2–13.5] min, p = 0.0003) and fewer RF applications (71 [54.8–83.8] vs. 103 [88.5–120.5], p < 0.0001) in the GA group. No major complications occurred. The 6-month AF recurrence rate was comparable between the groups (21.2% vs. 33.3%, p = 0.15). Conclusion: In patients undergoing high-power, short-duration RFCA for AF, the use of GA is associated with better procedural efficiency while simultaneously associated with an early recurrence rate comparable to MCS. [ABSTRACT FROM AUTHOR]

Sudden cardiac death (SCD) is responsible for a high percentage of cardiovascular fatalities, with ventricular arrhythmias being the most common cause. Despite numerous clinically available antiarrhythmic drugs (AADs), AADs retain some undesirable arrhythmic effects, and their inappropriate use can lead to severe adverse reactions. The exploration of new therapeutic options against arrhythmias with fewer unreceptive effects is of utmost importance. The ethanolic extracts of seven Cupressaceae species, namely, Chamaecyparis obtusa, Juniperus chinensis (L.) Ant., Sabina chinensis (L.) Ant. cv. Kaizuca, Platycladus orientalis (L.) Franco, Juniperus sabina L., Fokienia hodginsii, and Juniperus chinensis 'Pyramidalis' were investigated for their pharmacological effects on barium chloride (BaCl2)-induced arrhythmia using normal II lead electrocardiogram (ECG) measurements in a mouse model. According to the ECG profiles, pretreatment with C. obtusa, P. orientalis, and J. sabina extracts provoked dose-dependent protection against BaCl2-induced arrhythmia, while pretreatment with the other four species and amiodarone did not exert cardioprotective effects. The treatment effects were confirmed using a rat model. The therapeutic effects of C. obtusa, P. orientalis, and J. sabina extracts on the M2 and M3 receptors but not the M1 receptor were mediated by the inhibition of the M2 receptor blocker (methoctramine tetrahydrochloride), M3 antagonist (4-DAMP), or M1 receptor blocker (pirenzepine dihydrochloride). This first-line evidence illustrates that certain Cupressaceae species possess active antiarrhythmic components. The first line of key findings revealed that active components of certain Cupressaceae species have cardioprotective effects, suggesting that these innovative phytochemicals have promising potential for preventing the occurrence of cardiac arrhythmia and reducing sudden cardiac death. [ABSTRACT FROM AUTHOR]

Simple Summary: Hypertrophic cardiomyopathy is the most common acquired heart disease of cats. Arrhythmias are frequently observed in cats with hypertrophic cardiomyopathy, contributing to the complexity of the condition. Understanding rhythm disturbances associated with feline hypertrophic cardiomyopathy is crucial, as they could contribute to diagnosing the condition, risk stratification, and therapeutic management. By analyzing the current level of knowledge regarding arrythmias associated with feline hypertrophic cardiomyopathy, this study aimed to assess the utility of available diagnostic methods. Even though progress has been made in understanding arrythmias linked to hypertrophic cardiomyopathy, further research is needed to better assess their diagnostic and prognostic value, as well as the potential benefits of anti-arrhythmic therapy for affected cats. Hypertrophic cardiomyopathy (HCM) is a common heart disease in cats, characterized by regional or diffuse hypertrophy of the left ventricular walls, with an uncertain etiology and heterogenous natural history. Several types of rhythm disturbances are often associated with the disease. This study conducts a comprehensive review of the current literature, in order to evaluate the diagnostic and prognostic effectiveness of electrocardiography and Holter monitoring in the management of feline hypertrophic cardiomyopathy. The main subjects of discussion will include general information about HCM and its connection to arrhythmias. We will explore the rhythm disturbances documented in the current literature on Holter monitoring, as well as the techniques used for Holter monitoring. Additionally, the review will cover classical electrocardiography (ECG) and its diagnostic utility. Prognostic indicators and anti-arrhythmic therapy will also be discussed in detail. The findings highlight the importance of understanding arrhythmias in feline HCM for accurate diagnosis, risk assessment, and therapeutic intervention. ECG and Holter monitoring may offer valuable insights into managing feline HCM. [ABSTRACT FROM AUTHOR]

Obesity is a chronic disease that is rapidly increasing in prevalence and affects more than 600 million adults worldwide, and this figure is estimated to increase by at least double by 2030. In the United States, more than one-third of the adult population is either overweight or obese. The global obesity epidemic is a major risk factor for the development of life-threatening arrhythmias occurring in patients with long QT, particularly in conditions where multiple heart-rate-corrected QT-interval-prolonging mechanisms are simultaneously present. In obesity, excess dietary fat in adipose tissue stimulates the release of immunomodulatory cytokines such as interleukin (IL)-6, leading to a state of chronic inflammation in patients. Over the last decade, increasing evidence has been found to support IL-6 signaling as a powerful predictor of the severity of heart diseases and increased risk for ventricular arrhythmias. IL-6′s pro-inflammatory effects are mediated via trans-signaling and may represent a novel arrhythmogenic risk factor in obese hearts. The first selective inhibitor of IL-6 trans-signaling, olamkicept, has shown encouraging results in phase II clinical studies for inflammatory bowel disease. Nevertheless, the connection between IL-6 trans-signaling and obesity-linked ventricular arrhythmias remains unexplored. Therefore, understanding how IL-6 trans-signaling elicits a cellular pro-arrhythmic phenotype and its use as an anti-arrhythmic target in a model of obesity remain unmet clinical needs. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the clinical course and outcomes of post-COVID myocarditis in patients with cardiomyopathies (CMP). This case series includes 10 patients with different CMPs who had COVID-19 (seven men; 48.4 ± 11.4 yr.): left ventricular non-compaction (n = 2), arrhythmogenic right ventricular CMP in combination with a heterozygous form of hemochromatosis (n = 1, HFE), restrictive CMP (n = 1, MyBPC3), laminopathy (n = 1, LMNA), dilated cardiomyopathy (n = 1, MYH7 + MyBPC3), Danon's disease (n = 1, LAMP2) and AL cardiac amyloidosis (n = 3). Myocardial morphological examination with immunohistochemical staining and PCR for SARS-CoV-2 and cardiotropic viruses was performed in six patients, while cardiac MRI and anti-cardiac antibody titres were evaluated in all patients. Post-COVID lymphocytic myocarditis was confirmed morphologically in six patients (with LVNC, RCM, ARCV, Danon's disease, and AL amyloidosis). Spike and nucleocapsid coronavirus proteins were detected in cell infiltrates, endothelium and cardiomyocytes in all biopsies; SARS-CoV-2 RNA was found in five out of six. In four patients, the diagnosis of myocarditis was based on MRI, high titres of anti-cardiac antibodies and clinical data. The mean time from COVID-19 to the diagnosis of myocarditis was 7 (5; 10.5) months. Myocarditis manifested with the onset/increase of arrhythmias and heart failure. Immunosuppressive therapy with corticosteroids was administered to six patients and led to an increase in ejection fraction and improvement of heart failure symptoms in five of them. CMPs are a favourable background for the development of post-COVID myocarditis. The onset or deterioration of heart failure and/or arrhythmias in patients with CMPs after COVID-19 requires the exclusion of myocarditis and, if present, the administration of immunosuppressive therapy. [ABSTRACT FROM AUTHOR]