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Introduction Methods and Results Conclusion The decremental properties of the nodoventricular pathway (NVP) are uncertain.During short RP supraventricular tachycardia, a His‐refractory premature ventricular contraction (PVC) consistently terminated the tachycardia without atrial capture immediately after the PVC. Whereas a slightly earlier PVC failed to reset the subsequent His but terminated the tachycardia without atrial capture one cycle later.These observations are diagnostic of slow‐fast atrioventricular nodal reentrant tachycardia (AVNRT) with a bystander concealed‐NVP and can be explained by decremental properties in the NVP itself; greater prematurity of the PVC resulted in more decremental conduction over the NVP, causing the AVNRT termination one cycle later. [ABSTRACT FROM AUTHOR]

This document is a collection of references for articles related to the study of cardiac physiology and arrhythmias. The articles cover various topics, including calcium handling abnormalities in atrial fibrillation, the role of specific channels in atrial fibroblasts, the contribution of reactive oxygen species to the Frank-Starling mechanism, optical mapping of contracting hearts, and the role of specific channels in calcium-dependent triggered activity and cardiac arrhythmias. The articles provide valuable insights into the mechanisms and potential treatments for different cardiac conditions. The authors of the articles are funded by various organizations, including the German Cardiac Society, the Canadian Institutes of Health Research, and the Heart and Stroke Foundation of Canada. [Extracted from the article]

Background Methods Results Conclusions One of the most commonly experienced symptoms of premenstrual disorder (PMD) is anxiety, and there is a notable rise in sympathomimetic activity in this patient group. Studies have linked fluctuations in systemic autonomic tone to electrocardiography (ECG) changes. This study aims to investigate the relationship between anxiety, a common symptom of PMD, and alterations in QT dispersion (QTd) and P‐wave dispersion (Pd) in adolescent females.This cross‐sectional study included female adolescents aged 12–18 with regular menstruation for at least 3 months. Participants completed the premenstrual syndrome scale (PMSS) and were divided into two groups, PMD and control, according to the PMSS score. A standard 12‐lead body surface ECG was performed and QTd and Pd values were determined in each participant.Of the 43 participants, 27 were categorized into the PMD group, with a mean age of 15.15 ± 1.43 years. Age at menarche and menstrual cycle patterns were comparable between the PMD and control groups. Statistical analysis revealed significantly higher Pmin (p = 0.010) and Pd values (p < 0.001) in the PMD group compared to controls. A positive correlation between PMSS scores and Pd (p = 0.049) was also observed.Changes in atrial conduction and ventricular repolarization due to the pathophysiology of PMD may increase the risk of developing atrial and ventricular tachyarrhythmias over time. Screening patients with PMD using an ECG may be useful in identifying potentially at‐risk adolescents. [ABSTRACT FROM AUTHOR]

Background: Recently, treatment of equine atrial tachycardia by three‐dimensional electro‐anatomical mapping (3D EAM) and radiofrequency catheter ablation (RFCA) has been described. Myocardial sleeves in the caudal vena cava and pulmonary veins are a potential trigger for initiation and perpetuation of atrial tachycardia and atrial fibrillation in the horse. Isolation of these myocardial sleeves by RFCA may be an effective treatment for these arrhythmias. Objectives: To describe the feasibility of 3D EAM and RFCA to isolate caudal vena cava and pulmonary veins in adult horses using 3D mapping and a contact force (CF)‐guided ablation system. Study design: In vivo experiments. Methods: 3D EAM and RFCA was performed in five horses without cardiovascular disease under general anaesthesia, using the CF‐guided system CARTO®3. Point‐by‐point RFCA aimed for isolation of caudal vena cava and pulmonary veins. Radiofrequency energy was delivered in power‐controlled mode with a target power of 45 W, CF between 10 and 15 g and 30 mL/min irrigation rate, until an ablation‐index of 450–500 was reached. Results: In the right atrium, myocardial sleeves of the caudal vena cava were isolated (n = 5). In the left atrium, isolation of ostium II (n = 3), ostium III (n = 1) and ostium I, II and III en bloc (n = 1) was performed. Successful isolation was confirmed by entrance and exit block. Main limitations: Horses were euthanised at the end of the procedure, so long term effects such as potential reconnection of isolated veins could not be studied. Conclusions: This is the first description of 3D EAM and RFCA with CARTO®3 in horses, thereby showing the technical feasibility and successful caudal vena cava and pulmonary vein isolation. CF measurement allowed monitoring of catheter‐tissue contact, resulting in efficient acute lesion creation as confirmed by entrance and exit block. This is a promising treatment for cardiac arrhythmias in horses. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is a rarely reported arrhythmia in otherwise healthy newborn foals, with a single case of cardioversion using procainamide administration described in the literature. Two neonatal Thoroughbred colts were presented to an equine hospital because of an irregularly irregular tachyarrhythmia and poor latching when trying to nurse. History, physical examination, and initial diagnostic testing including ECG and echocardiography confirmed AF without structural heart disease. The 1st foal converted into normal sinus rhythm after treatment with IV metoprolol and quinidine. The 2nd foal converted to normal sinus rhythm after a single IV dose of metoprolol, intended for rate control. Demeanor and nursing behavior improved markedly after conversion. The 2 foals had normal heart rates and sinus rhythm that persisted for 6 weeks until euthanasia in the 1st foal and for 2 years in the 2nd foal. Rate control and cardioversion should be considered as a treatment for persistent lone AF in neonatal foals. [ABSTRACT FROM AUTHOR]

Aim Materials and Methods Results Conclusions We aimed to investigate the long‐term impact of glucagon‐like peptide‐1 receptor agonists (GLP‐1 RAs) on thyroid function, cardiovascular health, renal outcomes and adverse events in individuals with obesity and without type 2 diabetes (T2D).In this observational cohort study, we used propensity score matching to construct comparable cohorts of individuals with obesity and without T2D who were new to GLP‐1 RA treatment and those who did not receive glucose‐lowering medications. In total, 3,729,925 individuals with obesity were selected from the TriNetX Global Network, with an index event between 1 January 2016 and 31 March 2024. The primary outcomes were safety, cardiovascular, thyroid and clinical biochemical profile outcomes occurring within 5 years following the index event.After propensity score matching, the study included 12,123 individuals in each group. GLP‐1 RA treatment was associated with a significantly lower risk of all‐cause mortality (hazard ratio 0.23; 95% confidence interval 0.15–0.34) and several cardiovascular complications, including ischaemic heart disease, heart failure, arrhythmias, hypertension, stroke and atrial fibrillation (all p < 0.05). GLP‐1 RAs were also associated with a lower risk of acute kidney injury and allergic reactions. These protective effects were consistent across various subgroups and regions.In this large observational study, GLP‐1 RAs showed long‐term protective effects on cardiovascular health, renal outcomes and adverse events in individuals with obesity and without T2D. Our findings suggest that GLP‐1 RAs may offer a comprehensive approach to managing obesity and its related comorbidities, potentially improving overall health and survival in this population. [ABSTRACT FROM AUTHOR]

Background Objectives Methods Results Conclusion Chimeric antigen receptor T‐cell (CAR‐T) therapy has shown promise in treating hematologic malignancies, yet its potential cardiotoxic effects require thorough investigation.We aim to conduct a systematic review and meta‐analysis to examine the cardiotoxic effects of CAR‐T therapy in adults with hematologic malignancies.We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials for studies reporting cardiovascular outcomes, such as arrhythmias, heart failure, and reduced left ventricle ejection fraction (LVEF).Our analysis of 20 studies involving 4789 patients revealed a 19.68% incidence rate of cardiovascular events, with arrhythmias (7.70%), heart failure (5.73%), and reduced LVEF (3.86%) being the most prevalent. Troponin elevation was observed in 23.61% of patients, while NT‐Pro‐BNP elevation was observed in 9.4. Subgroup analysis showed higher risks in patients with pre‐existing conditions, such as atrial arrhythmia (OR 3.12; p < .001), hypertension (OR 1.85; p = .002), previous heart failure (OR 3.38; p = .003), and coronary artery disease (OR 2.80; p = .003).Vigilant cardiovascular monitoring is crucial for patients undergoing CAR‐T therapy to enhance safety and treatment efficacy.Novelty Statements. [ABSTRACT FROM AUTHOR]

Identifying and treating pediatric arrhythmias is essential for pediatric anesthesiologists. Pediatric patients can present with narrow or wide complex tachycardias, though the former is more common. Patients with inherited channelopathies or cardiomyopathies are at increased risk. Since most pediatric patients present for anesthesia without a baseline electrocardiogram, the first identification of an arrhythmia may occur under general anesthesia. Supraventricular tachycardia, the most common pediatric tachyarrhythmia, represents a broad category of predominately narrow complex tachycardias. Stimulating events including intubation, vascular guidewire manipulation, and surgical stimulation can trigger episodes. Valsalva maneuvers are unreliable as treatment, making adenosine or other intravenous antiarrhythmics the preferred acute therapy. Reentrant tachycardias are the most common supraventricular tachycardia in pediatric patients, including atrioventricular reciprocating tachycardia (due to a distinct accessory pathway) and atrioventricular nodal reentrant tachycardia (due to an accessory pathway within the atrioventricular node). Patients with ventricular preexcitation, often referred to as Wolff‐Parkinson‐White syndrome, have a wide QRS with short PR interval, indicating antegrade conduction through the accessory pathway. These patients are at risk for sudden death if atrial fibrillation degenerates into ventricular fibrillation over a high‐risk accessory pathway. Automatic tachycardias, such as atrial tachycardia and junctional ectopic tachycardia, are causes of supraventricular tachycardia in pediatric patients, the latter most typically noted after cardiac surgery. Patients with inherited arrhythmia syndromes, such as congenital long QT syndrome, are at risk of developing ventricular arrhythmias such as polymorphic ventricular tachycardia (Torsades de Pointes) which can be exacerbated by QT prolonging medications. Patients with catecholaminergic polymorphic ventricular tachycardia are at particular risk for developing bidirectional ventricular tachycardia or ventricular fibrillation during exogenous or endogenous catecholamine surges. Non‐selective beta blockers are first line for most forms of long QT syndrome as well as catecholaminergic polymorphic ventricular tachycardia. Anesthesiologists should review the impact of medications on the QT interval and transmural dispersion of repolarization, to limit increasing the risk of Torsades de Pointes in patients with long QT syndrome. This review explores the key anesthetic considerations for these arrhythmias. [ABSTRACT FROM AUTHOR]

Hypoglycemia is common in people with type 1 diabetes. Sometimes, severe hypoglycemia can be fatal. The underlying mechanisms by which severe hypoglycemia can lead to death are unclear. The sympathetic nervous system is thought to be proarrhythmic. We hypothesized that norepinephrine is the main mediator of severe hypoglycemia‐induced fatal cardiac arrhythmias. To test this hypothesis, adult, non‐diabetic Sprague–Dawley rats were subjected to hyperinsulinemic‐severe hypoglycemic clamps (3 h, 10–15 mg/dL) during two different experiments: (1) intracerebroventricular (ICV) norepinephrine (n = 26) or artificial cerebrospinal fluid (aCSF) (n = 20) infusion or (2) blockade of norepinephrine release by intraperitoneal reserpine (n = 20) or control (n = 29). In experiment 1, brain norepinephrine infusion during severe hypoglycemia led to a 2.5‐fold increase in third‐degree heart block and a 24% incidence of ST elevation compared to no ST elevation in aCSF controls. In experiment 2, reserpine successfully reduced plasma and cardiac norepinephrine levels. During severe hypoglycemia, reserpine completely prevented second and third‐degree heart block and T wave increases, a marker of myocardial infarction, compared to controls. In conclusion, norepinephrine increases while reserpine, used to reduce norepinephrine nerve terminal release, reduces heart block and markers of myocardial infarction during severe hypoglycemia. [ABSTRACT FROM AUTHOR]

Objectives Methods Results Conclusions This study aims to investigate the occurrence, type and correlation of early and late atrial arrhythmias following mitral valve repair in patients with no preoperative history of atrial arrhythmias.Patients undergoing mitral valve (MV) repair for degenerative disease were included. Early and late postoperative electrocardiograms were evaluated for the incidence and type of atrial arrhythmia (atrial fibrillation [AF] or atrial tachycardia [AT]).The 192 patients were included. Early atrial arrhythmias occurred in 100/192 (52.1%) patients; AF in 61 (31.8%) patients, early AT in 15 (7.8%) and both in 24 (12.5%). In total 89% of patients were discharged in sinus rhythm. During a follow‐up time of 7.3 years, 14 patients (7.3%) died and 49 (25.5%) patients developed late atrial arrhythmias. At 10 years, the cumulative incidence of any late atrial arrhythmia, with death as competing risk, was 64% (95% confidence interval [CI] = 55%–72%). On Fine‐Gray model analysis, only early postoperative AF lasting >24 h was related to the development of late AF (hazard ratio 5.99, 95% CI = 1.78%–20.10%, p = .004). Early postoperative ATs were related to the development of late tachycardias, independent of their duration (<24 h hazard ratio 4.25, 95% CI = 1.89–9.57, p = .001 and >24 h hazard ratio 3.51, 95% CI = 1.65–7.46, p = .001).Early and late atrial arrhythmias were common after MV repair surgery. Only early postoperative AF lasting >24 h was a risk factor for the occurrence of late AF. Conversely, any postoperative AT was correlated to the development of late ATs. [ABSTRACT FROM AUTHOR]

This article explores the role of ryanodine receptors (RyR2) in calcium handling in the heart and questions the current understanding of calcium flux balance. The author suggests that the interpretation of experimental observations on calcium handling may be oversimplified, which could hinder the development of new therapeutic agents for heart failure and arrhythmias. The article also discusses the effects of caffeine on calcium transients and the potential contribution of reverse mode sodium-calcium exchange (NCX). The authors propose a hypothesis that reverse mode NCX during the early stages of the action potential allows for efficient uptake of calcium into the sarcoplasmic reticulum (SR) by sarcoplasmic reticulum calcium ATPase (SERCA). They suggest that the effects of caffeine on SR calcium content may be due to its diastolic effects rather than its effects on calcium release during action potentials. The authors call for further experiments to test their hypothesis and emphasize the importance of understanding the timing and balance of calcium fluxes in the heart for cardiac contraction and arrhythmias. [Extracted from the article]

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

Voltage‐gated potassium channels are expressed throughout the human body and are essential for physiological functions. These include delayed rectifiers, A‐type channels, outward rectifiers, and inward rectifiers. They impact electrical function in the heart (repolarization) and brain (repolarization and stabilization of the resting membrane potential). KCNQx and KCNHx encode Kv7.x and Kv11.x proteins, which form delayed rectifier potassium channels. KCNQx and KCNHx channelopathies are associated with both cardiac and neuronal pathologies. These include electrocardiographic abnormalities, cardiac arrhythmias, sudden cardiac death (SCD), epileptiform discharges, seizures, bipolar disorder, and sudden unexpected death in epilepsy (SUDEP). Due to the ubiquitous expression of KCNQx and KCNHx channels, abnormalities in their function can be particularly harmful, increasing the risk of sudden death. For example, KCNH2 variants have a dual role in both cardiac and neuronal pathologies, whereas KCNQ2 and KCNQ3 variants are associated with severe and refractory epilepsy. Recurrent and uncontrolled seizures lead to secondary abnormalities, which include autonomics, cardiac electrical function, respiratory drive, and neuronal electrical activity. Even with a wide array of anti‐seizure therapies available on the market, one‐third of the more than 70 million people worldwide with epilepsy have uncontrolled seizures (i.e., intractable/drug‐resistant epilepsy), which negatively impact neurodevelopment and quality of life. To capture the current state of the field, this review examines KCNQx and KCNHx expression patterns and electrical function in the brain and heart. In addition, it discusses several KCNQx and KCNHx variants that have been clinically and electrophysiologically characterized. Because these channel variants are associated with multi‐system pathologies, such as epileptogenesis, Kv7 channel modulators provide a potential anti‐seizure therapy, particularly for people with intractable epilepsy. Ultimately an increased understanding of the role of Kv channels throughout the body will fuel the development of innovative, safe, and effective therapies for people at a high risk of sudden death (SCD and SUDEP). [ABSTRACT FROM AUTHOR]

Mitral valve prolapse is a common valve disorder that usually has a benign prognosis unless there is significant regurgitation or LV impairment. However, a subset of patients are at an increased risk of ventricular arrhythmias and sudden cardiac death, which has led to the recognition of "arrhythmic mitral valve prolapse" as a clinical entity. Emerging risk factors include mitral annular disjunction and myocardial fibrosis. While echocardiography remains the primary method of evaluation, cardiac magnetic resonance has become crucial in managing this condition. Cine magnetic resonance sequences provide accurate characterization of prolapse and annular disjunction, assessment of ventricular volumes and function, identification of early dysfunction and remodeling, and quantitative assessment of mitral regurgitation when integrated with flow imaging. However, the unique strength of magnetic resonance lies in its ability to identify tissue changes. T1 mapping sequences identify diffuse fibrosis, in turn related to early ventricular dysfunction and remodeling. Late gadolinium enhancement sequences detect replacement fibrosis, an independent risk factor for ventricular arrhythmias and sudden cardiac death. There are consensus documents and reviews on the use of cardiac magnetic resonance specifically in arrhythmic mitral valve prolapse. However, in this article, we propose an algorithm for the broader use of cardiac magnetic resonance in managing this condition in various scenarios. Future advancements may involve implementing techniques for tissue characterization and flow analysis, such as 4D flow imaging, to identify patients with ventricular dysfunction and remodeling, increased arrhythmic risk, and more accurate grading of mitral regurgitation, ultimately benefiting patient selection for surgical therapy. [ABSTRACT FROM AUTHOR]

Brugada syndrome (BrS) is a cardiac electrophysiological disease with unknown etiology, associated with sudden cardiac death. Symptomatic patients are treated with implanted cardiac defibrillator, but no risk stratification strategy is effective in patients that are at low to medium arrhythmic risk. Cardiac computational modeling is an emerging tool that can be used to verify the hypotheses of pathogenesis and inspire new risk stratification strategies. However, to obtain reliable results computational models must be validated with consistent experimental data. We reviewed the main electrophysiological and structural variables from BrS clinical studies to assess which data could be used to validate a computational approach. Activation delay in the epicardial right ventricular outflow tract is a consistent finding, as well as increased fibrosis and subclinical alterations of right ventricular functional and morphological parameters. The comparison between other electrophysiological variables is hindered by methodological differences between studies, which we commented. We conclude by presenting a recent theory unifying electrophysiological and structural substrate in BrS and illustrate how computational modeling could help translation to risk stratification. [ABSTRACT FROM AUTHOR]

Following new concepts by Bichat in the early 19th century, of organic and animal life centered around the ganglionic nervous system, over 100 years of anatomic studies and physiologic experimentation eventually resulted in Gaskell's 1916 book entitled "The Involuntary Nervous System" and Langley's 1921 book entitled "The Autonomic Nervous System." Neurology and cardiology emerged as specialties of medicine in the early 20th century. Although neurology made several prominent discoveries in neurophysiology during the first half of the 20th century, cardiology developed coronary care units and cardiac catheterization in the 1960s. Programmed electrical stimulation of the heart and noninvasive ambulatory monitoring provided new methodologies to study clinical cardiac arrhythmias. Experimentally, direct cardiac nerve stimulation of sympathetic nerve endings, as well as parasympathetic control of the atrioventricular node, provided the background to new detailed autonomic studies of the heart. Neurocardiology, perhaps initially more directed towards our understanding of sudden cardiac death, ultimately embraced an even significantly more complex scheme of local circuit neurons and near‐endless loops of interconnecting neurons in the heart. Intrathoracic extracardiac and intracardiac ganglia have been recharacterized, both anatomically and physiologically, laying the groundwork for potential new therapies of cardiac neuromodulation. [ABSTRACT FROM AUTHOR]

Summary: This analysis investigated the incidence of sudden deaths (SDs) and non‐fatal and fatal ventricular arrhythmias (VAs) in five acalabrutinib clinical trials. In total, 1299 patients received acalabrutinib (exposure, 4568.4 patient‐years). Sixteen (1.2%) patients experienced SD or VA (event rate, 0.350/100 patient‐years). Non‐fatal VAs occurred in 11 (0.8%) patients, nine (0.7%) of whom had premature ventricular contractions only. SD and fatal VAs occurred in five (0.4%) patients (event rate, 0.109/100 patient‐years; median time to event: 46.2 months). SDs and VAs with acalabrutinib occurred at low rates, and there are insufficient data to point to an increased risk of SD or VA with acalabrutinib. [ABSTRACT FROM AUTHOR]

Background: Cholinesterase inhibitors (ChEIs) are regularly used in Alzheimer's disease. Of the three ChEIs approved for dementia, donepezil is among the most prescribed drugs in the United States with nearly 6 million prescriptions in 2020; however, it is classified as a "known risk" QT interval‐prolonging medication (QTPmed). Given this claim is derived from observational data including single case reports, we aimed to evaluate high‐quality literature on the frequency and nature of proarrhythmic major adverse cardiac events (MACE) associated with donepezil. Methods: We searched Medline, Embase, International Pharmaceutical Abstracts, and Cochrane Central from 1996 onwards for randomized controlled trials (RCTs) involving patients age ≥18 years comparing donepezil to placebo. The MACE composite included mortality, sudden cardiac death, non‐fatal cardiac arrest, Torsades de pointes, ventricular tachyarrhythmia, seizure or syncope. Random‐effects meta‐analyses were performed with a treatment‐arm continuity correction for single and double zero event studies. Results: Sixty RCTs (n = 12,463) were included. Twenty‐five of 60 trials (n = 5886) investigated participants with Alzheimer's disease and 33 trials monitored electrocardiogram data. The mean follow‐up duration was 31 weeks (SD = 36). Mortality was the most commonly reported MACE (252/331, 75.8% events), the remainder were syncope or seizures, with no arrhythmia events. There was no increased risk of MACE with exposure to donepezil compared to placebo (risk ratio [RR] 1.08, 95% CI 0.88–1.33, I2 = 0%) and this was consistent in the subgroup analysis of trials including participants with cardiovascular morbidities (RR 1.14, 95% CI 0.88–1.47). Subgroup analysis suggested a trend toward more events with donepezil with follow‐up ≥52 weeks (RR: 1.32, 0.98–1.79). Conclusions: This systematic review with meta‐analysis found donepezil may not be arrhythmogenic. Donepezil was not associated with mortality, ventricular arrhythmias, seizure or syncope, although longer durations of therapy need more study. Further research to clarify actual clinical outcomes related to QTPmed is important to inform prescribing practices. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the incidence, clinical characteristics, and risk factors of moxifloxacin‐related arrhythmias and electrocardiographic alterations in hospitalized patients using real‐world data. Concurrently, a nomogram was established and validated to provide a practical tool for prediction. Retrospective automatic monitoring of inpatients using moxifloxacin was performed in a Chinese hospital from January 1, 2017, to December 31, 2021, to obtain the incidence of drug‐induced arrhythmias and electrocardiographic alterations. Propensity score matching was conducted to balance confounders and analyze clinical characteristics. Based on the risk and protective factors identified through logistic regression analysis, a prediction nomogram was developed and internally validated using the Bootstrap method. Arrhythmias and electrocardiographic alterations occurred in 265 of 21,711 cases taking moxifloxacin, with an incidence of 1.2%. Independent risk factors included medication duration (odds ratio [OR] 1.211, 95% confidence interval [CI] 1.156–1.270), concomitant use of meropenem (OR 4.977, 95% CI 2.568–9.644), aspartate aminotransferase >40 U/L (OR 3.728, 95% CI 1.800–7.721), glucose >6.1 mmol/L (OR 2.377, 95% CI 1.531–3.690), and abnormally elevated level of amino‐terminal brain natriuretic peptide precursor (OR 2.908, 95% CI 1.640–5.156). Concomitant use of cardioprotective drugs (OR 0.430, 95% CI 0.220–0.841) was a protective factor. The nomogram showed good differentiation and calibration, with enhanced clinical benefit. The incidence of moxifloxacin‐related arrhythmias and electrocardiographic alterations is in the range of common. The nomogram proves valuable in predicting the risk in the moxifloxacin‐administered population, offering significant clinical applications. [ABSTRACT FROM AUTHOR]

Key Clinical Message: CA of LVS premature beats complexes is difficult due to anatomical limitations. We report a patient with PVCs originating from the LVS region who was successfully ablated by ablation. Catheter ablation (CA) of premature ventricular contractions (PVCs) arising from the left ventricular summit (LVS) presents technical challenges due to the regional anatomy and frequently intramural site of origin. Herein, we demonstrated a case of a successful CA, originating from the LVS region. We further discussed the detailed anatomical background and clinical feasibility of CA as an alternative ablation route for PVCs originating from the LVS. [ABSTRACT FROM AUTHOR]

Objective: Posterior left atrial wall isolation (PWI) plus traditional pulmonary vein isolation (PVI) has been proposed as a promising intervention to decrease atrial fibrillation (AF) recurrence. We aim to investigate the efficacy and safety of adding PWI to the traditional PVI in patients with AF. Methods: A systematic review and meta‐analysis was conducted using synthesizing randomized controlled trials (RCTs) retrieved by systematically searching PubMed, Web of Science, SCOPUS, EMBASE, and Cochrane through June 14, 2023. We used Stata version 17 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD), with a 95% confidence interval (CI) (PROSPERO ID: CRD42023446227). Results: We included 11 RCTs with a total number of 1534 patients. Combined ablation with PWI + PVI was not associated with any significant difference over PVI only regarding the recurrence of clinical AF (RR: 0.86 with 95% CI [0.70–1.06]), all atrial arrhythmia (RR: 0.93 with 95% CI [0.82–1.07]), nonatrial fibrillation arrhythmia (RR: 1.22 with 95% CI [0.97–1.53]), early AF (RR: 0.89 with 95% CI [0.62–1.27]), and antiarrhythmic drugs at discharge (RR: 0.83 with 95% CI [0.67–1.04]). However, it was associated with increased total ablation duration (minutes) (MD: 12.58 with 95% CI [6.80–18.37]) and total procedure duration (minutes) (MD: 16.77 with 95% CI [9.63–23.91]), without any significant difference regarding adverse events (RR: 1.05 with 95% CI [0.63–1.74]). Conclusion: While the pooled data from PWI + PVI using point‐by‐point radiofrequency did not suggest a benefit in the recurrence of various atrial arrhythmias compared to PVI alone, PWI+PVI using direct posterior wall ablation, especially with cryoballoon, demonstrated a significant reduction in recurrence of AF/atrial arrhythmias. Also, PWI + PVI significantly increased the ablation and total procedure durations. [ABSTRACT FROM AUTHOR]

Introduction: Patients with Brugada syndrome (BrS) face an increased risk of ventricular arrhythmias and sudden cardiac death. Implantable cardiac monitors (ICMs) have emerged as effective tools for detecting arrhythmias in BrS. Technological advancements, including temperature sensors and improved subcutaneous electrocardiogram (subECG) signal quality, hold promise for further enhancing their utility in this population. Methods and results: We present a case of a 40‐year‐old man exhibiting a BrS type 2 pattern on 12‐lead ECG, who underwent ICM insertion (BIOMONITOR IIIm, BIOTRONIK) due to drug‐induced BrS type 1 pattern and a history of syncope, with a negative response to programmed ventricular stimulation. The device contains an integrated temperature sensor and can transmit daily vital data, such as mean heart rate and physical activity. Several months later, remote alerts indicated a temperature increase, along with transmitted subECGs suggesting a fever‐induced BrS type 1 pattern. The patient was promptly advised to commence antipyretic therapy. Over the following days, remotely monitored parameters showed decreases in mean temperature, physical activity, and mean heart rate, without further recurrence of abnormal subECGs. Conclusion: ICMs offer valuable insights beyond arrhythmia detection in BrS. Early detection of fever using embedded temperature sensors may improve patient management, while continuous subECG morphological analysis has the potential to enhance risk stratification in BrS patients. [ABSTRACT FROM AUTHOR]

In the field of cardiac electrophysiology, there is a universal desire: the discovery of a flawless diagnostic maneuver for supraventricular tachycardias (SVTs). This is not merely a wish but a shared odyssey. To improve diagnostic accuracy and achieve sufficient sensitivity and specificity, numerous diagnostic maneuvers have been proposed. However, each has its limitations and prompts a search for new diagnostic techniques. This continuous cycle of discovery and refinement, which we titled "SVT Quest" is reviewed in chronological sequence. This adventure in diagnosing narrow QRS tachycardia unfolds in 3 steps: Step 1 involves differentiating atrial tachycardia from other SVTs based on the observations such as V‐A‐V or V‐A‐A‐V response, ΔAA interval, VA linking, the last entrainment sequence, and response to the atrial extrastimulus. Step 2 focuses on differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia based on the observations such as tachycardia reset upon the premature ventricular contraction during His refractoriness, uncorrected/corrected postpacing interval, differential ventricular entrainment, orthodromic His capture, transition zone analysis, and total pacing prematurity. Step 3 characterizes the concealed nodoventricular/nodofascicular pathway and His‐ventricular pathway‐related tachycardia based on observations such as V‐V‐A response, ΔatrioHis interval, and paradoxical reset phenomenon. There is no single diagnostic maneuver that fits all scenarios. Therefore, the ability to apply multiple maneuvers in a case allows the operator to accumulate evidence to make a likely diagnosis. Let's embark on this adventure! [ABSTRACT FROM AUTHOR]

Background: Evidence regarding the association between hyperuricemia and arrhythmia recurrence after catheter ablation for paroxysmal atrial fibrillation (AF) is scarce. We investigated whether hyperuricemia predicts arrhythmia recurrence after catheter ablation for paroxysmal AF and the relationship between hyperuricemia and alcohol consumption in AF recurrence. Methods: Patients who underwent catheter ablation for paroxysmal AF were divided into the hyperuricemia (index serum uric acid [UA] >7.0 mg/dL; n = 114) and control (UA ≤7.0 mg/dL; n = 609) groups and were followed for a median of 24 (12–48) months after ablation. Results: The hyperuricemia group had more patients with an alcohol intake of ≥20 g/day (33.3% vs. 22.7%, p =.017) and a lower incidence of AF‐free survival (p =.019). Similarly, those with an alcohol intake of ≥20 g/day had a lower incidence of AF‐free survival than other patients. Multivariate Cox regression analysis revealed the following independent predictors of AF recurrence (adjusted hazard ratio, 95% confidence interval): hyperuricemia (1.64, 1.12–2.40), female gender (1.91, 1.36–2.67), brain natriuretic peptide level >100 pg/mL (1.59, 1.14–2.22), and alcohol consumption ≥20 g/day (1.49, 1.03–2.15) (all p <.05). In addition, causal mediation analysis revealed that alcohol consumption of ≥20 g/day directly affected AF recurrence, independent of hyperuricemia. Conclusions: Patients with hyperuricemia may be at a high risk of arrhythmia recurrence after catheter ablation for paroxysmal AF. Although high alcohol consumption may contribute to increased UA levels, the presence of hyperuricemia may independently predict AF recurrence. [ABSTRACT FROM AUTHOR]

Background: Laser balloon (LB) pulmonary vein isolation (PVI) is an established ablation technique for atrial fibrillation (AF). We report long‐term follow‐up and procedural data of LB‐PVI and we compare the first and second LB generation. Methods: Patients undergoing LB ablation with first‐ (LB1) or second‐generation LB (LB2) for AF were retrospectively enrolled and divided into two groups. Procedural endpoint was complete PVI. Clinical success was defined as no recurrence of AF/atrial tachycardia after a 90 days blanking period. Results: 538 patients were included (age 66 ± 10 years, 58% paroxysmal AF), 427 in LB1 and 111 in LB2. 2079 PVs were targeted and 2073 (99.7%) were successfully isolated; 2027 (97.5%) using solely the LB. Additional touch‐up ablation was limited (46 PVs; 2.2%) with no difference between the groups. Procedural (LB1: 120 ± 33 minutes vs. LB2: 99 ± 22 min; p <.001) and fluoroscopy time (LB1: 11.2 ± 5 min vs. LB2: 8.5 ± 3 min; p <.001) were shorter with LB2. The complication rate was 8.9% (LB1: 10.1% vs. LB2: 4.5%; p =.067) with most complications resulting from the access site (21/48). Overall freedom from AF after 1‐year was 73.7% (paroxysmal AF: 76.9%; persistent AF: 69.3%; p <.001) with no difference between the groups (LB1: 73.4% vs. LB2: 74.7%; p =.491). Conclusion: LB showed a high efficacy and acceptable safety, with numerically lower complication rates with the second‐generation LB. Procedure and fluoroscopy times were shorter with LB2. Overall, 73.7% of patients were free from AF at 1‐year, with comparable results among both generations. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation in the pediatric population using fluoroscopy has been known to cause adverse events. This study aims to assess the effectiveness and safety of zero fluoroscopy (ZF) and near‐ZF‐guided catheter ablation for the treatment of arrhythmias in the pediatric population. Methods: The PubMed, Embase, and Cochrane library databases were searched and reviewed for relevant studies. Outcomes of interest include safety, short‐term, and long‐term effectiveness. We classified patients ≤21 years old who underwent ZF or near‐ZF ablation with fluoroscopy time ≤1.5 min as our study group and patients within the same age range who underwent conventional fluoroscopy and/or near‐ZF ablation with a mean fluoroscopy time >1.5 min as our control group. Both ZF and near‐ZF ablation utilized 3D‐electroanatomical mapping (3D‐EAM). Results: Ten studies composed of 2279 patients were included in this study. Total fluoroscopy time (MD –15.93 min, 95% CI (−22.57 – (−9.29), p <.001; I2 = 84%)) and total procedural time (MD –22.06 min, 95% CI (−44.39 – (−0.28), p <.001; I2 = 88%)) were significantly lower in the near‐ZF group. Both ZF and near‐ZF demonstrated a trend towards improved success rates compared to conventional fluoroscopy but did not achieve statistical significance for all subgroup analyses. Ablation in the study group also decreased incidence of complication compared to the control (RR 0.35; 95% CI (0.14–0.90); p =.03; I2 = 0%). Conclusion: ZF and near‐ZF ablation reduced the overall duration, compares in effectiveness, and shows a superior safety profile compared to control group. [ABSTRACT FROM AUTHOR]

Background: There is ongoing debate around rate versus rhythm control strategies for managing atrial fibrillation (AF), however, much of the data comes from Western cohorts. Kerala‐AF represents the largest prospective AF cohort study from the Indian subcontinent. Objectives: To compare 12‐month outcomes between rate and rhythm control strategies. Methods: Patients aged ≥18 years with non‐transient AF were recruited from 53 hospitals across Kerala. Patients were stratified by rate or rhythm control. The primary outcome was a composite of all‐cause mortality, arterial thromboembolism, acute coronary syndrome or hospitalization due to heart failure or arrhythmia at 12 months. Secondary outcomes included bleeding events and individual components of the primary. Predictors of the composite outcome were analysed by logistic regression. Results: A total of 2901 patients (mean age 64.6 years, 51% female) were included (2464 rate control, 437 rhythm control). Rates of the primary composite outcome did not differ between groups (29.7% vs 30.0%; p =.955), nor did any component of the primary. Bleeding outcomes were also similar (1.6% vs 1.9%; p =.848). Independent predictors of the primary composite outcome were older age (aOR 1.01; p =.013), BMI <18 (aOR 1.51; p =.025), permanent AF (aOR 0.78; p =.010), HFpEF (aOR 1.40; p =.023), HFrEF (aOR 1.39; p =.004), chronic kidney disease (aOR 1.36; p <.001), and prior thromboembolism (aOR 1.31; p =.014). Conclusion: In the Kerala‐AF registry, 12‐month outcomes did not differ between rate and rhythm control cohorts. [ABSTRACT FROM AUTHOR]

Introduction: Atrial fibrillation (AF) represents the most common arrhythmia in the postoperative setting. We aimed to investigate the incidence of postoperative AF (POAF) and determine its predictors, with a specific focus on inflammation markers. Methods: We performed a retrospective single tertiary center cohort study including consecutive adult patients who underwent a major surgical procedure between January 2016 and January 2020. Patients were divided into four subgroups according to the type of surgery. Results: Among 53,387 included patients (79.4% male, age 64.5 ± 9.5 years), POAF occurred in 570 (1.1%) with a mean latency after surgery of 3.4 ± 2.6 days. Ninety patients died (0.17%) after a mean of 13.7 ± 8.4 days. The 28‐day arrhythmia‐free survival was lower in patients undergoing lung and cardiovascular surgery (p <.001). Patients who developed POAF had higher levels of C‐reactive protein (CRP) (0.70 ± 0.03 vs. 0.40 ± 0.01 log10 mg/dl; p <.001). In the multivariable Cox regression analysis, adjusting for confounding factors, CRP was an independent predictor of POAF [HR per 1 mg/dL increase in log‐scale = 1.81 (95% CI 1.18–2.79); p =.007]. Moreover, independent predictors of POAF were also age (HR/1 year increase = 1.06 (95% CI 1.04–1.08); I <.001), lung and cardiovascular surgery (HR 23.62; (95% CI 5.65–98.73); p <.001), and abdominal and esophageal surgery (HR 6.26; 95% CI 1.48–26.49; p =.013). Conclusions: Lung and cardiovascular surgery had the highest risk of POAF in the presented cohort. CRP was an independent predictor of POAF and postsurgery inflammation may represent a major driver in the pathophysiology of the arrhythmia. [ABSTRACT FROM AUTHOR]

Background: Diagnosis of Brugada syndrome (BrS) may be established by exposing a Type 1 Brugada pattern using a sodium channel blocker. Data on the outcomes of different patient populations with drug‐induced Type 1 Brugada pattern are limited. The present study reports on the characteristics and outcome of subjects with ajmaline induced Type 1 Brugada pattern. Methods: A multicenter retrospective study including all consecutive cases of ajmaline‐induced Type 1 Brugada pattern from seven centers. Results: A total of 260 patients (69.9% males, mean age 43.4 ± 13.5) were included. Additional characteristics included history of syncope (n = 56, 21.5%), family history of BrS (n = 58, 22.3%) or sudden cardiac death (n = 47, 18.1%) and ventricular fibrillation (n = 3, 1.2%). Patients were divided into those meeting current diagnostic criteria for drug‐induced BrS (DIBrS) and compared to the drug‐induced Brugada pattern (DIBrECG). Females were significantly overrepresented in the DIBrS group (n = 50, 40% vs. n = 29, 21.5%, p =.001). A significantly higher prevalence of type 2/3 Brugada ECG at baseline was found in the DIBrECG group (n = 108, 80.8% vs. n = 75, 60% in the DIBrS, p =.026). During a median follow up of three (IQR 1.50–5.32) years, a single event of significant arrhythmia occurred in the DIBrS group. Conclusion: Less than half of subjects with ajmaline‐induced Brugada pattern met current criteria for BrS. These individuals had very low rate of adverse outcomes during a follow up of 3 years, irrespective of the indication for the test or eligibility for the BrS diagnosis. [ABSTRACT FROM AUTHOR]

This article discusses a case report of two sisters with hypertrophic cardiomyopathy (HCM) who exhibit differences in genetic mutations and clinical presentation. HCM is a genetic disorder characterized by thickening of the heart muscle. The sisters both experienced symptoms such as chest pain and palpitations, but one sister also had a cerebral infarction. Genetic testing revealed mutations in the MYH7 and RYR2 genes in both sisters, while the younger sister carried an additional mutation in the AKAP9 gene. The findings suggest that different mutations can lead to variations in the severity and clinical manifestations of HCM. Further research is needed to understand the role of AKAP9 in HCM. [Extracted from the article]

Background: Atrial fibrillation (AF) and obesity coexist in approximately 37.6 million and 650 million people globally, respectively. The anatomical and physiological changes in individuals with obesity may influence the pharmacokinetic properties of drugs. Aim: This review aimed to describe the evidence of the effect of obesity on the pharmacokinetics of antiarrhythmics in people with AF. Methods: Three databases were searched from inception to June 2023. Original studies that addressed the use of antiarrhythmics in adults with AF and concomitant obesity were included. Results: A total of 4549 de‐duplicated articles were screened, and 114 articles underwent full‐text review. Ten studies were included in this narrative synthesis: seven cohort studies, two pharmacokinetic studies, and a single case report. Samples ranged from 1 to 371 participants, predominately males (41%–85%), aged 59–75 years, with a body mass index (BMI) of 23–66 kg/m2. The two most frequently investigated antiarrhythmics were amiodarone and dofetilide. Other drugs investigated included diltiazem, flecainide, disopyramide, propafenone, dronedarone, sotalol, vernakalant, and ibutilide. Findings indicate that obesity may affect the pharmacokinetics of amiodarone and sodium channel blockers (e.g., flecainide, disopyramide, and propafenone). Factors such as drug lipophilicity may also influence the pharmacokinetics of the drug and the need for dose modification. Discussion: Antiarrhythmics are not uniformly affected by obesity. This observation is based on heterogeneous studies of participants with an average BMI and poorly controlled confounding factors such as multimorbidity, concomitant medications, varying routes of administration, and assessment of obesity. Controlled trials with stratification at the time of recruitment for obesity are necessary to determine the significance of these findings. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Early‐onset atrial fibrillation (AF) has already been observed in approximately 2% of patients with genetically proven long QT syndrome (LQTS). This frequency is higher than population‐based estimates of early‐onset AF. However, the concomitant expression of AF in LQTS is likely underestimated. The purpose of this study was to examine the clinical presentation, genetic background, and outcomes of a cohort of patients with LQTS and early‐onset AF referred to a single tertiary center.Twenty‐seven patients diagnosed with congenital LQTS were included in the study based on the documentation of early‐onset (age ≤50 years) clinical or subclinical AF episodes in all available medical records, including standard electrocardiograms, wearable monitor or cardiac implantable electronic devices.Seventeen patients experienced clinical AF during the follow‐up period. Subclinical AF was detected in 10 patients through insertable or wearable cardiac monitors. In our series, the mean heart rate during AF episodes was found to be relatively low despite the patients' young age and the low or minimal effective doses of beta‐blockers used for QTc interval control. All patients exhibiting LQTS and early‐onset AF were genotype positive, carrying mutations in the KCNQ1 (66%), KCNH2, KCNE1, and SCN5A genes. Notably, most of these patients carried the same p.(R231C) mutation in the KCNQ1 gene (59%) and were from the same families, suggesting concurrent expression of familial AF and LQTS.LQTS patients are prone to developing clinical and subclinical AF, even at a younger age. The occurrence of early‐onset AF in the LQTS population could be more frequent than previously assumed. AF should be considered as a potential dysrhythmia related to LQTS. Our study emphasizes the importance of carefully researching clinical and/or subclinical episodes of AF through strict heart rhythm monitoring in the LQTS population. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the prevalence of likely pathogenic or pathogenic variants and assess the diagnostic yield from genetic testing for cardiac arrhythmias in Norway since 2003. Data from 1991 probands and 2782 relatives were retrospectively collected from the laboratory information management system at Unit for Cardiac and Cardiovascular Genetics, Oslo University hospital. Of 1991 probands, 57.4% were females, age at genetic testing was 33.1 (±22.7) years, and 32.5% were under the age of 18. A likely pathogenic or pathogenic variant (including 14 novel) was detected in 15.4% in total. Of the 2782 relatives, 53.7% were females, age at genetic testing was 35.6 (±22.5) years, 27.3% were under the age of 18, and 45.3% carried the family variant. Probands and relatives combined, 1/3356 persons in the Norwegian population were heterozygous for an arrhythmia‐causing variant. The founder variant p.Q530X (NM_000218.2: c.1588C>T) in KCNQ1 accounted for 34% of all variants in Norway. In conclusion, genetic testing provided a genetic basis of the arrhythmia in 15.4% of the probands. Familial cascade screening identified four times as many variant‐positive relatives, allowing early detection and prompt stratification of arrhythmic risk of those variant carriers. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion The anterior and lateral position of the anterolateral papillary muscle (ALPM) has found to be reached with better catheter stability and less mechanical bumping via the transseptal (TS) compared to the retrograde aortic (RA) approach. The aim of this study is to compare the TS and RA approaches on mapping and ablation of ventricular arrhythmias (VAs) arising from ALPMs.Thirty‐two patients with ALPM‐VAs undergoing mapping and ablation via the TS approach were included and compared with 31 patients via the RA approach within the same period. Acute success was compared, as well as other outcomes including misinterpreted mapping results due to bumping, radiofrequency (RF) attempts, procedural time and success rate at 12‐month follow‐up.Acute success was achieved in more cases in the TS group (96.4% vs. 72.0%, p = .020). During activation mapping, bump‐provoked premature ventricular complexes (PVCs) misinterpreted as clinical PVCs were more common in the RA group (30.0% vs. 58.3%, p = .036), leading to more RF attempts (3.5 ± 2.7 vs. 7.2 ± 6.8, p = .006). Suppression of VAs were finally achieved in the unsuccessful cases by changing to the alternative approach, but the procedural time was significantly less in the TS group (90.0 ± 33.0 vs. 113.7 ± 41.1 min, p = .027) with less need to change the approach, although follow‐up success rates were similar (75.0% vs. 71.0%, p = .718).A TS rather than RA approach as the initial approach appears to facilitate mapping and ablation of ALPM‐VAs, specifically by decreasing the possibility of misleading mapping results caused by bump‐provoked PVC, and increase the acute success rate thereby. [ABSTRACT FROM AUTHOR]

Background Objective Methods and Results Conclusions Glucagon‐like peptide‐1 receptor agonists (GLP‐1 RAs) are new anti‐hyperglycaemic drugs with proven cardiovascular (CV) benefit in diabetic and non‐diabetic patients at high CV risk. Despite a neutral class effect on arrhythmia risk, data on semaglutide suggest a possible drug‐specific benefit in reducing atrial fibrillation (AF) occurrence.To perform a meta‐analysis of randomized clinical trials (RCTs) to assess the risk of incident AF in patients treated with semaglutide compared to placebo.Ten RCTs were included in the analysis. Study population encompassed 12,651 patients (7285 in semaglutide and 5366 in placebo arms), with median follow‐up of 68 months. A random effect meta‐analytic model was adopted to pool relative risk (RR) of incident AF. Semaglutide reduces the risk of AF by 42% (RR .58, 95% CI .40–.85), with low heterogeneity across the studies (I2 0%). At subgroup analysis, no differences emerged between oral and subcutaneous administration (oral: RR .53, 95% CI .23–1.24, I2 0%; subcutaneous: RR .59, 95% CI .39–.91, I2 0%; p‐value .83). In addition, meta‐regression analyses did not show any potential influence of baseline study covariates, in particular the proportion of diabetic patients (p‐value .14) and body mass index (BMI) (p‐value .60).Semaglutide significantly reduces the occurrence of incident AF by 42% as compared to placebo in individuals at high CV risk, mainly affected by type 2 diabetes mellitus. This effect appears to be consistent independently of the route of administration of the drug (oral or subcutaneous), the presence of underlying diabetes and BMI. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusions The programing of subcutaneous implantable cardioverter‐defibrillators (S‐ICD) in clinical practice has been little studied, as the activation status of the SMART Pass filter, which was implemented to reduce inappropriate shocks.We assessed device programing during follow‐up and the rate of detected arrhythmias in consecutive S‐ICD recipients.We analyzed data from 670 S‐ICD patients followed on the remote network at 17 Italian centers for a median of 31 months (25th–75th percentile: 16–51). The enhanced SMART Pass version, introduced in October 2022, was expected to reduce the unintentional deactivation rate.At the latest remote data transmission, the median conditional zone cut‐off was set to 210 bpm (25th–75th percentile: 200–220), the shock zone cutoff was 250 bpm (25th–75th percentile: 240–250), and the SMART Pass was enabled in 586 (87%) patients. During follow‐up, 194 automatic deactivation events were reported in 118 (18%) patients. Shocks were delivered in 129 (19%) patients, and untreated arrhythmias were recorded in 136 (20%) patients. The rate of shocks was lower when SMART Pass was enabled ‐0.12/patient‐year (95% CI: 0.10–0.14) versus 0.20 (95% CI: 0.15–0.26) (p = .002), as it was the rate of untreated arrhythmias ‐0.12/patient‐year (95% CI: 0.11–0.14) versus 0.23 (95% CI: 0.18–0.30) (p = .001). The enhanced SMART Pass version was associated with a lower rate of deactivations ‐0.04/patient‐year (95% CI: 0.02–0.05) versus 0.14 (95% CI: 0.12–0.16) (p < .001), and with a reduction in treated and untreated arrhythmias (Incidence rate ratios: 0.40 (95% CI: 0.28–0.53) and 0.40 (95% CI: 0.30–0.55), respectively (p < .001)).Centers tend to program devices to detect high ventricular rates for arrhythmia detection, to minimize inappropriate shock occurrences. SMART Pass activation is associated with lower rates of detected and treated arrhythmias. The enhanced SMART Pass version seems associated with a lower deactivation rate and with a further decrease in treated arrhythmias. [ABSTRACT FROM AUTHOR]

Introduction Methods and Results Conclusion Catheter‐based radiofrequency (RF) ablation is generally regarded as the standard approach for patients with ventricular tachycardia (VT) refractory to antiarrhythmic drug therapy and may be considered as a first‐line approach when there is a preference to avoid these agents. Patients with a history of cardiac surgery may have VT substrate inaccessible to catheter ablation due to intervening prosthetic materials or scar.This article describes a 55‐year‐old patient with a history of surgically repaired subvalvular aortic stenosis and subsequent valve‐sparing root replacement who presented with sustained VT. After RF ablation failed due to VT substrate “guarded” by graft material, retrograde coronary venous ethanol ablation (RCVEA) was employed to successfully treat the clinical VT.RCVEA ablation can be useful for treating VT when conventional ablation is limited by inaccessible substrate due to prior cardiac surgery. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusions The impact of mRNA‐based coronavirus disease‐2019 (COVID‐19) vaccines on atrial arrhythmias (AA) and ventricular arrhythmias incidence is unknown.BIOTRONIK Home Monitoring data and Medicare Claims data were utilized to identify individuals implanted with a cardiac implantable electronic device (CIED) between 2010 and 2020 who received one or more doses of COVID‐19 vaccine in 2021. The burden of AA (%) in the 3 months postvaccination was compared to those noted in the preceding 3 months using the Wilcoxon signed rank test. Sub‐analyses comparing the effects of the influenza vaccine against the COVID‐19 vaccine were also evaluated for individuals who received the influenza vaccine in 2020. A 1:1 propensity score match comparison between COVID‐19 vaccine and non‐vaccinated patients was also performed.First and second doses of the COVID‐19 vaccine were administered to 7757 and 6579 individuals with a CIED (age 76.2 ± 9.0 years, 49% males), respectively. While a small but statistically significant increase in the burden of AA was noted in the 3 months postvaccination compared to the preceding 3 months after the first dose of the COVID‐19 vaccine (0.43 ± 9.04%, p = .028) a similar rise in AA was found following the influenza vaccine and for matched patients who did not receive the COVID‐19 vaccine. No significant difference in device therapies was seen pre‐ and postvaccination.Though we report a small but significant increase in the number of CIED‐detected AAs following vaccination for COVID‐19 over a 3‐month window, we believe these results correlate more with time and the progressive nature of AF rather than the vaccine itself. While these data should not dissuade from the use of these vaccines, increased vigilance and prompt treatment of AF is required for high‐risk groups, specifically males over 70 years of age, following vaccination. [ABSTRACT FROM AUTHOR]

Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary bypass device commonly used to treat cardiac arrest in children. The American Heart Association guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care recommend using amiodarone as a first‐line agent to treat ventricular arrhythmias in children with cardiac arrest. However, there are no dosing recommendations for amiodarone to treat ventricular arrhythmias in pediatric patients on ECMO. Amiodarone has a high propensity for adsorption to the ECMO components due to its physicochemical properties leading to altered pharmacokinetics (PK) in ECMO patients. The change in amiodarone PK due to interaction with ECMO components may result in a difference in optimal dosing in patients on ECMO when compared with non‐ECMO patients. To address this clinical knowledge gap, a physiologically‐based pharmacokinetic model of amiodarone was developed in adults and scaled to children, followed by the addition of an ECMO compartment. The pediatric model included ontogeny functions of cytochrome P450 (CYP450) enzyme maturation across various age groups. The ECMO compartment was parameterized using the adsorption data of amiodarone obtained from ex vivo studies. Model predictions captured observed concentrations of amiodarone in pediatric patients with ECMO well with an average fold error between 0.5 and 2. Model simulations support an amiodarone intravenous (i.v) bolus dose of 22 mg/kg (neonates), 13 mg/kg (infants), 8 mg/kg (children), and 6 mg/kg (adolescents). This PBPK modeling approach can be applied to explore the dosing of other drugs used in children on ECMO. [ABSTRACT FROM AUTHOR]

Objectives Methods Results Conclusions Post‐cardiotomy extracorporeal life support (ECLS) cannulation might occur in a general post‐operative ward due to emergent conditions. Its characteristics have been poorly reported and investigated This study investigates the characteristics and outcomes of adult patients receiving ECLS cannulation in a general post‐operative cardiac ward.The Post‐cardiotomy Extracorporeal Life Support (PELS) is a retrospective (2000–2020), multicenter (34 centers), observational study including adult patients who required ECLS for post‐cardiotomy shock. This PELS sub‐analysis analyzed patients´ characteristics, in‐hospital outcomes, and long‐term survival in patients cannulated for veno‐arterial ECLS in the general ward, and further compared in‐hospital survivors and non‐survivors.The PELS study included 2058 patients of whom 39 (1.9%) were cannulated in the general ward. Most patients underwent isolated coronary bypass grafting (CABG, n = 15, 38.5%) or isolated non‐CABG operations (n = 20, 51.3%). The main indications to initiate ECLS included cardiac arrest (n = 17, 44.7%) and cardiogenic shock (n = 14, 35.9%). ECLS cannulation occurred after a median time of 4 (2–7) days post‐operatively. Most patients' courses were complicated by acute kidney injury (n = 23, 59%), arrhythmias (n = 19, 48.7%), and postoperative bleeding (n = 20, 51.3%). In‐hospital mortality was 84.6% (n = 33) with persistent heart failure (n = 11, 28.2%) as the most common cause of death. No peculiar differences were observed between in‐hospital survivors and nonsurvivors.This study demonstrates that ECLS cannulation due to post‐cardiotomy emergent adverse events in the general ward is rare, mainly occurring in preoperative low‐risk patients and after a postoperative cardiac arrest. High complication rates and low in‐hospital survival require further investigations to identify patients at risk for such a complication, optimize resources, enhance intervention, and improve outcomes. [ABSTRACT FROM AUTHOR]

Introduction Methods and Results Conclusion Patients with viral myocarditis can present with challenging life‐threatening arrhythmias. Catheter ablation can be a life‐saving procedure in some patients with recurrent drug‐refractory ventricular arrhythmias.A patient with three prior ablations targeting two different monomorphic ventricular tachycardias (MMVTs) presented with recurrent ventricular tachycardia (VT). Consequently, he underwent epicardial mapping with adjuvant AI‐enabled CT images with the creation of a three‐dimensional model, which demonstrated a midmyocardial scar. Fractionated potentials were noted during mapping in this region, and entrainment suggested an inner loop. Interestingly, pacing showed two different QRS morphologies identical to his previously ablated VTs with a long stim‐QRS at this region. Epicardial ablation carried on during the VT successfully terminated it, but the VT remained inducible and required endocardial ablation to make it noninducible.This case emphasizes the importance of recognizing possible three‐dimensional VT circuits in some patients and the need to understand and target mid‐myocardial substrate from both the endocardium and epicardium to achieve the elimination of the VT circuits. [ABSTRACT FROM AUTHOR]

Smart healthcare systems integrated with advanced deep neural networks enable real‐time health monitoring, early disease detection, and personalized treatment. In this work, a novel 3D AND‐type flash memory array with a rounded double channel for computing‐in‐memory (CIM) architecture to overcome the limitations of conventional smart healthcare systems: the necessity of high area and energy efficiency while maintaining high classification accuracy is proposed. The fabricated array, characterized by low‐power operations and high scalability with double independent channels per floor, exhibits enhanced cell density and energy efficiency while effectively emulating the features of biological synapses. The CIM architecture leveraging the fabricated array achieves high classification accuracy (93.5%) for electrocardiogram signals, ensuring timely detection of potentially life‐threatening arrhythmias. Incorporated with a simplified spike‐timing‐dependent plasticity learning rule, the CIM architecture is suitable for robust, area‐ and energy‐efficient in‐memory arrhythmia detection systems. This work effectively addresses the challenges of conventional smart healthcare systems, paving the way for a more refined healthcare paradigm. [ABSTRACT FROM AUTHOR]

Background Materials and Methods Results Conclusion Endless loop tachycardia (ELT) is the commonest pacemaker mediated tachycardia (PMT) encountered among patients with cardiac implantable electronic devices (CIEDs). Despite being enabled with various preventive algorithms, we encountered several cases having recurrent, long, and symptomatic ELT.We retrospectively analyzed consecutive device checkups at device clinic at a single center of eastern India between January 2019 to March 2023.There were 20 cases of confirmed and sustained ELT among 4520 device checks. Although mostly benign, in two cases ELT led to clinical worsening in patients having left ventricular (LV) systolic dysfunction. Even with good ventricular function, ELT resulted in improper atrioventricular (AV) synchrony leading to disabling symptom in one case. The differentiation of ELT from sinus tachycardia and atrial tachycardia (AT) was not always easy. Magnet application is certainly useful to differentiate. The situations that provoked ELT in this study were—long AV delays, VIP (ventricular intrinsic preferences)/MVP (managed ventricular pacing), atrial non‐capture, atrial under/over sensing, premature ventricular contractions (PVCs)/couplets, premature atrial contractions (PAC) and slower ventriculo‐atrial (VA) conduction. Rate responsive shortening of post‐ventricular atrial refractory period (PVARP) also promoted its occurrence and hindered troubleshooting. When ELT occurred despite post‐PVC extension of PVARP, lowering the atrial sensitivity, switching to bipolar sensing and manual setting of longer PVARP after measuring VA conduction time were useful. “Rate responsive PVARP” had to be turned off in a few cases to prevent ELT. On the contrary, an over aggressive prolongation of PVARP led to repetitive non‐reentrant ventriculo‐atrial synchrony (RNRVAS) in two cases. Checking VA conduction during implantation and noninvasive program stimulation (NIPS) during follow up were useful to check the tendency for ELT.Clinically significant ELT is rare but not uncommon among devices having in‐built preventive algorithms. Manual adjustments are often useful to troubleshoot the same. [ABSTRACT FROM AUTHOR]

This article discusses a case of narrow complex tachycardia with alternating atrial activation. The patient had previously undergone an ablation procedure for pre-excited atrial fibrillation but experienced recurrent episodes of palpitations. The article explores the mechanism behind the alternating atrial activation and suggests that it may be due to conduction block across the mitral isthmus. The left lateral pathway was successfully ablated, resulting in the resolution of the tachycardia. Further research and mapping techniques are recommended to improve the accuracy of ablation procedures. [Extracted from the article]

Usmani‐Riazuddin syndrome (USRISR, MIM# 619548; USRISD, MIM#619467) is a very rare genetic condition. recently associated with deleterious variants in AP1G1 (MIM* 603533). It is characterized by multisystemic involvement including intellectual disability, speech and developmental delay, behavioral anomalies, muscular tone disorders, seizures, limb defects, and unspecified facial gestalt. In this report, we describe this syndrome for the second time, in association to a novel AP1G1 variant identified in a toddler with multisystemic involvement including intellectual disability, speech and developmental delay, behavioral anomalies, arrhythmias, hearing loss, skin changes, and limb defects. Next generation sequencing (NGS) analysis through clinical exome disclosed AP1G1: c.1969C>G (p.Leu657Val), de novo, likely pathogenic variant, according to ACMG classification criteria. Proband's facial features resembled the spectrum of chromatinopathies. Clinical pictures were analyzed and a clinical overlap was supported by DeepGestalt analysis (www.face2gene.com). The system identified 6 chromatin disorders out of 30 possible diagnoses. The remaining 24 included 9 miscellaneous cryptic chromosomal abnormalities (excluded due to normal microarray study). To the best of our knowledge, this is the first description of likely distinctive facial features in a patient with Usmani‐Riazuddin syndrome. Further multicentric analyses are needed for a better definition of this aspect. [ABSTRACT FROM AUTHOR]

Genetic missense variants in TNNI3K, encoding troponin‐I interacting kinase, have been associated with dilated cardiomyopathy (DCM) and observed in families with supraventricular tachycardias (SVT). Previously, a family harboring the TNNI3K‐c.1615A > G (p.Thr539Ala) variant presented with congenital junctional ectopic tachycardia (CJET), an arrhythmia that arises from the atrioventricular (AV) node and His bundle. However, this was a relatively small four‐generational family with limited genetic testing (N = 3). We here describe a multigenerational family with CJET harboring a novel ultra‐rare TNNI3K variant: TNNI3K‐c.1729C > T (p.Leu577Phe). Of all 18 variant carriers, 13 individuals presented with CJET, resulting in a genetic penetrance of 72%. In addition, CJET is reported in another small family harboring TNNI3K‐c.2225C > T (p.Pro742Leu). Similar to the previously published CJET family, both TNNI3K variants demonstrate a substantial reduction of kinase activity. Our study contributes novel evidence supporting the involvement of TNNI3K genetic variants as significant contributors to CJET, shedding light on potential mechanisms underlying this cardiac arrhythmia. [ABSTRACT FROM AUTHOR]

Introduction: The accuracy of surface ECG algorithms for predicting the origin of outflow tract ventricular arrhythmias (OT‐VAs) might be questioned. Intracardiac electrograms recorded at anatomic landmarks could provide new predictive insights. We aim to evaluate the efficacy of a novel criterion utilizing the activation pattern of the coronary sinus (CS) in localizing OT‐VAs, including VAs originating from the right ventricular outflow tract (RVOT), endocardial left ventricular outflow tract (Endo‐LVOT), and epicardial left ventricular outflow tract (Epi‐LVOT). Methods: We measured the ventricular activation time of the mitral annulus (MA) from the onset of the earliest QRS complex of VAs to the initial deflection over the isoelectric line at local signals, namely the QRS‐MA interval. The activation at 3 and 12 o'clock of the MA was recorded as the QRS‐MA3 and QRS‐MA12 intervals, respectively. Their predictive values were compared to previous ECG algorithms. Results: A total of 68 patients with OT‐VAs were enrolled (51 for development and 17 for validation). From early to late, the ventricular activation sequences at MA12 were as follows: Epi‐LVOT, Endo‐LVOT, and RVOT. In LBBB morphology OT‐VAs, the QRS‐MA12 interval was significantly earlier for LVOT origins than RVOT origins. In the combined cohort of development and validation cohort, a cut‐off value of ≤10 ms predicted the LVOT origin with a sensitivity of 100% and specificity of 78%. The QRS‐MA12 interval ≤ −24 ms additionally predicted epicardial LVOT sites of origin. Conclusions: The QRS‐MA interval could accurately differentiate the OT‐VAs localization. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 69-year-old female who underwent an electrophysiological study due to recurrent supraventricular tachycardia (SVT). It highlighted the occurrence of a wide complex tachycardia (WCT) and explored the mechanism behind its transformation following a premature ventricular complex (PVC). Treatment discussed involved radiofrequency ablation targeting the base of the triangle of Koch, which successfully eliminated SVT inducibility and potentially the NFV pathway.