Proposed diagnostic criteria for the Brugada syndrome: consensus report

Brugada Syndrome and Kawasaki Disease in a Two-Year-Old: A Case of Double Jeopardy

Brugada syndrome (BrS) is a genetic channelopathy that may predispose to ventricular arrhythmia. It is inherited as an autosomal dominant pattern with incomplete penetrance. Fever can unmask Brugada syndrome in children who have a genetic predisposition. Kawasaki disease is not known to be associated with Brugada syndrome; however, it may lead to cardiac complications such as coronary artery abnormalities and myocardial inflammation. We report a case of a two-year-old who was diagnosed with Kawasaki disease and subsequently developed Brugada syndrome.

Long-term prognosis of patients with an SCN5A loss-of-function variant and progressive cardiac conduction disorder or Brugada syndrome

BACKGROUND

The long-term prognosis of patients with a loss-of-function variant in the cardiac sodium channel gene SCN5A is unknown.

OBJECTIVE

This study aimed to evaluate the long-term arrhythmic risk in patients with an SCN5A loss-of-function variant to identify predictors of arrhythmic events.

METHODS

Probands and family members with (likely) pathogenic SCN5A loss-of-function variants were retrospectively included. Clinical and electrocardiographic data at baseline and last follow-up were collected. Patients with a history of cardiac arrest, sustained ventricular tachycardia, symptomatic or documented atrial tachy- or bradyarrhythmia, or arrhythmogenic syncope were categorized as symptomatic. Arrhythmic events at follow-up were defined as sudden death, aborted cardiac arrest, documented ventricular fibrillation, and/or sustained ventricular tachycardia.

RESULTS

We included 615 patients (349 men, 242 probands, 157 with a spontaneous type 1 Brugada electrocardiogram, and 111 symptomatic at baseline). During a median follow-up of 9.5 (Q1,Q3 5.0-14.3) years, arrhythmic events occurred in 41 patients (6.7%), equating an overall event rate of 0.7%/y: 2.0%/y in symptomatic and 0.3%/y in asymptomatic patients. In the overall study population, symptoms at baseline, male sex, and QRS prolongation were identified as independent predictors of arrhythmic events. In asymptomatic patients, male sex and QRS prolongation were also identified as predictors. Asymptomatic women with QRS interval < 100 ms did not experience arrhythmic events at follow-up.

CONCLUSION

Key predictors of arrhythmic risk in patients with an SCN5A loss-of-function variant, regardless of a Brugada syndrome diagnosis, are symptoms at baseline, male sex, and prolonged QRS interval. Our findings may enable more tailored management strategies in patients with an SCN5A loss-of-function variant based on their individual risk profiles.

Zebrafish as a Model System for Brugada Syndrome

Brugada syndrome (BrS) is an inheritable cardiac arrhythmogenic disease, associated with an increased risk of sudden cardiac death. It is most common in males around the age of 40 and the prevalence is higher in Asia than in Europe and the United States. The pathophysiology underlying BrS is not completely understood, but several hypotheses have been proposed. So far, the best effective treatment is the implantation of an implantable cardioverter-defibrillator (ICD), but device-related complications are not uncommon. Therefore, there is an urgent need to improve diagnosis and risk stratification and to find new treatment options. To this end, research should further elucidate the genetic basis and pathophysiological mechanisms of BrS. Several experimental models are being used to gain insight into these aspects. The zebrafish (Danio rerio) is a widely used animal model for the study of cardiac arrhythmias, as its cardiac electrophysiology shows interesting similarities to humans. However, zebrafish have only been used in a limited number of studies on BrS, and the potential role of zebrafish in studying the mechanisms of BrS has not been reviewed. Therefore, the present review aims to evaluate zebrafish as an animal model for BrS. We conclude that zebrafish can be considered as a valuable experimental model for BrS research, not only for gene editing technologies, but also for screening potential BrS drugs.

Clinical differences between drug-induced type 1 Brugada pattern and syndrome

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.

An Interesting Case of Wolf-Parkinson-White Syndrome in a Young Patient With Sensorineural Deafness

Wolff-Parkinson-White (WPW) syndrome is a condition associated with tachycardia due to accessory pathways in the heart, and it is one of the most common causes of tachycardia in infants and children. WPW may also be associated with mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS syndrome) or LEOPARD syndrome (LS). We report a case of pre-excitation WPW syndrome in a 17-year-old man who was brought to the hospital by ambulance following the collapse. WPW syndrome type A was diagnosed from precordial leads. Electrocardiography (ECG) revealed a short PR interval, delta waves, and positive waves with dominant R in all pericardial leads. Blood test results showed an isolated elevated ALT level. Subsequent echocardiography was unremarkable, with an ejection fraction of 55%, apart from septal and inferior wall dyssynchrony. With regard to the past medical history, he had sensorineural deafness (SND) since childhood and had a family history of SND. Consequently, the patient was transferred to the cardiac electrophysiology department at another hospital after consultation and underwent ablation. A successful post-ablation electrocardiogram revealed the resolution of the WPW syndrome signs and post-ablation features, such as peak T waves.

Long-term follow-up of patients with Brugada syndrome: Foremost risk factors associated with overall arrhythmic events

Brugada syndrome (BS) is characterized by ST segment elevation in right precordial leads (V1-V3), ventricular tachycardia (VT), ventricular fibrillation (VF), and sudden cardiac death (SCD) in individuals without structural heart disease. The aim of this study is to contribute to the controversial issue of finding the most valuable marker that can predict poor prognosis during follow-up in patients with a diagnosis of BS. A total of 68 patients diagnosed with BS or had Brugada-type ECG change between January 1997 and July 2012 at the Department of Cardiology of Başkent University Faculty of Medicine, Ankara, Turkey, were included in this cohort study. Patients were screened every 6 months for arrhythmia-related syncope, SCD, appropriate and inappropriate defibrillation (shock), AF development and death; collectively defined as "arrhythmic events" and were the primary endpoints. Patients with and without arrhythmic events were compared. The mean age was 34.9 ± 12.2 years (9-71 years), and 52 (76.5%) patients were male. Mean follow-up was 49.6 ± 37.6 months (4-188 months). Univariate analysis showed that male sex (P = .004), type 1 electrocardiographic pattern (P = .008), SCD (P = .036), VT/VF history (P = .046), requirement for electrophysiological studies (P = .034), implantable cardioverter-defibrillator placement (P = .014) were found to demonstrate significant differences in patients with and without arrhythmic events. In multivariable analyzes, spontaneous type 1 ECG presence (HR = 8.54, 95% CI: 0.38-26.37; P = .003) and VT/VF history (HR = 9.21, 95% CI: 0.004-1.88; P = .002) were found to be independently associated with arrhythmic events. We found the presence of spontaneous type 1 ECG and a history of VT/VF to be associated with increased likelihood of overall arrhythmic events in BS. Given the higher risk of poor prognosis, we recommend additional measures in patients with BS who have these features.

[Cardiogenetics in Germany- a view and review]

The development of the cardiogenetics field in Germany has been increasing since the mid-1990s with many national contributions, some of them were really important and groundbreaking. The starting point was and still is the patient and his family, e.g. with a familial form of arrhythmia or cardiomyopathy, the clarification of the genetic cause and the personalized treatment of those being affected. The scientific, always translationally oriented interest in identifying a causative gene and uncovering the underlying pathomechanisms has led to notable contributions for Brugada syndrome, short QT syndrome and cardiac conduction disorders or sinus node dysfunction, but also in DCM or ARVC. What is important, however, is always the way back (bench > bed side): implementation of national and international recommendations for cardiogenetic diagnostics in daily cardiological routine and the personalized care and therapy of those being affected.

A Case Report of Brugada Syndrome Associated With Physical Trauma

Brugada syndrome is an autosomal dominant channelopathy that usually affects healthy young males without apparent structural heart disease. It is associated with a spectrum of variable and dynamic clinical manifestations, high risk of life-threatening ventricular arrhythmias, and sudden cardiac death. Our patient demonstrated transient and dynamic EKG changes of both type 1 (coved) and type 2 (saddleback) ST elevation, suggestive of the Brugada pattern that was associated with physical chest trauma and stressful situations. While common triggers like fever and certain drugs are well-recognized, this case illustrates the potential for physical stress and trauma to unmask or aggravate Brugada syndrome, albeit without definitive evidence for a causal link. Ultimately, this report underscores the importance of considering a broad differential diagnosis, including Brugada syndrome, in patients presenting with unexplained syncope or characteristic EKG changes, even when traditional triggers are absent.

Inherited Arrhythmias in the Pediatric Population: An Updated Overview

Pediatric cardiomyopathies (CMs) and electrical diseases constitute a heterogeneous spectrum of disorders distinguished by structural and electrical abnormalities in the heart muscle, attributed to a genetic variant. They rank among the main causes of morbidity and mortality in the pediatric population, with an annual incidence of 1.1-1.5 per 100,000 in children under the age of 18. The most common conditions are dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). Despite great enthusiasm for research in this field, studies in this population are still limited, and the management and treatment often follow adult recommendations, which have significantly more data on treatment benefits. Although adult and pediatric cardiac diseases share similar morphological and clinical manifestations, their outcomes significantly differ. This review summarizes the latest evidence on genetics, clinical characteristics, management, and updated outcomes of primary pediatric CMs and electrical diseases, including DCM, HCM, arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), long QT syndrome (LQTS), and short QT syndrome (SQTS).

Prevalence of Brugada electrocardiographic pattern in adult population - A community-based study from Kerala, South India

There is no data for Brugada electrocardiographic pattern (BrEP) from India. In a cross-sectional study of men and women between the ages 20-79 years, electrocardiograms were analyzed following the 2002 consensus. The overall prevalence of BrEP was 1.06 % (95 % CI 0.76, 1.35). There were two cases type I (0.04 %; 95 % CI 0.01, 0.06) and forty-seven type II/III (1.01 %; 95 % CI 1.02, 1.35); the pattern was markedly higher in men. In this study, BrEP was slightly less prevalent compared to South Asia but more than in the west.

Management of Arrhythmias in the Cardiovascular Intensive Care Unit

Arrhythmias in the cardiovascular intensive care unit (CVICU) can be difficult to manage because of the complex hemodynamic and respiratory states of critically ill patients. Treating physicians must be educated to prevent, diagnose, and treat a multitude of tachyarrhythmias and bradyarrhythmias. In this review article, the authors outline a pragmatic approach to patient assessment, arrhythmia diagnosis, and management of the most common arrhythmias seen in the CVICU.

Molecular Pathways and Animal Models of Arrhythmias

Arrhythmias account for over 300,000 annual deaths in the United States, and approximately half of all deaths are associated with heart disease. Mechanisms underlying arrhythmia risk are complex; however, work in humans and animal models over the past 25 years has identified a host of molecular pathways linked with both arrhythmia substrates and triggers. This chapter will focus on select arrhythmia pathways solved by linking human clinical and genetic data with animal models.

Can specific ECG markers identify a pharmacologically induced type 1 Brugada pattern? Insights from a large, single-center cohort

BACKGROUND

In patients with a type 2 or 3 Brugada pattern, the pharmacological (IC drugs) induction of a type 1 pattern confirms the diagnosis of Brugada syndrome.

OBJECTIVE

To evaluate the value of various ECG markers in predicting IC drug test results.

METHODS

We retrospectively analysed 443 consecutive patients referred to our Center (from January 2010 to December 2019) to undergo Ajmaline/Flecainide testing; all had a type 2 or 3 Brugada pattern or were relatives with Brugada syndrome. Clinical parameters and ECG markers (r1V1 and SV6 duration and amplitude, QRSV1/QRSV6 duration, V1 and V2 ST amplitude) were independently evaluated for their association to pharmacological test positivity, and a logistic regression model was applied.

RESULTS

The drug test was positive in 151 (34%) patients. On multivariate logistic regression analysis, age > 45 years, female gender, HR >60 bpm, QRSV1/QRSV6 duration >1 and non-isoelectric pattern in V2 were associated with a positive test. The percentage of patients who tested positive increased according to the presence of the above ECG markers (from 11.3% in the absence to 57.6% in the presence of both factors). During long-term follow-up, the clinical event rate was higher in patients with predictive ECG markers and very low in those without.

CONCLUSIONS

In our population we confirmed the ability of QRSV1/QRSV6 duration >1 and of a non-isoelectric pattern in V2 to predict a pharmacologically induced type 1 Brugada pattern. Patients with neither of these ECG markers had a rather low event rate during follow-up.

Case report: State-of-the-art risk-modifying treatment of sudden cardiac death in an asymptomatic patient with a mutation in the SCN5A gene and a review of the literature

Brugada syndrome is a rare hereditary disorder characterized by distinct ECG findings, complex genetics, and a high risk of sudden cardiac death. Recognition of the syndrome is crucial as it represents a paradigm of sudden death tragedy in individuals at the peak of their lives. Notably, Brugada syndrome accounts for more than 20% of sudden cardiac deaths in individuals with structurally normal hearts. Although this syndrome follows an autosomal dominant inheritance pattern, it is more prevalent and severe in males. Diagnosis is primarily based on the characteristic ECG pattern observed in the right precordial leads. Mutations in the SCN5A gene, resulting in loss of function, are the most common genetic cause. We presented a 36-year-old proband with a family history of sudden cardiac death. Although the patient was asymptomatic for Brugada syndrome, his father had experienced sudden death at the age of 36. The proband was admitted to St. Catherine's Specialty Hospital where blood was taken and subjected to next-generation sequencing (NGS) using a "Sudden cardiac death" panel. The analysis identified a pathogenic variant in the SCN5A gene [c.4222G > A(p.Gly1408Arg)], which is associated with autosomal dominant Brugada syndrome. Based on the positive genetic test result, the patient was referred for further examination. ECG with modified precordial lead positioning confirmed the presence of the Brugada phenotype, displaying the type-2 and type-1 ECG patterns. Therefore, we made the diagnosis and decided to implant an implantable cardioverter-defibrillator (ICD) based on the results of broad genetic NGS testing, diagnostic criteria (ECG), and considering the high burden of sudden cardiac death in the patient's family, as well as his concerns that limited his everyday activities. This case shows that genetics and personalized medicine hold immense potential in the primary prevention, diagnosis, and treatment of Brugada syndrome and sudden cardiac death.

Novelties in Brugada Syndrome: Complex Genetics, Risk Stratification, and Catheter Ablation

Brugada syndrome (BrS) is an inherited arrhythmia syndrome with distinctive electrocardiographic abnormalities in the right precordial leads and predisposes to ventricular arrhythmias and sudden cardiac death in otherwise healthy patients. Its complex genetic architecture and pathophysiological mechanism are not yet completely understood, and risk stratification remains challenging, particularly in patients at intermediate risk of arrhythmic events. Further understanding of its complex genetic architecture may help improving future risk stratification, and advances in management may contribute to alternatives to implantable cardioverter-defibrillators. Here, the authors review the latest insights and developments in BrS.

An Unusual First Presentation of Stroke and Seizure in a 32-Year-Old Patient With Brugada Syndrome Type 2 Electrocardiogram Pattern

We report a case of a 32-year-old lady who was admitted to the hospital with right-sided weakness that preceded an episode of seizure. On the day of admission, she woke up early in the morning with mild right-sided weakness and numbness. She had difficulty walking and later had a seizure, which was witnessed by her son. She had no signs of infection prior to this. She had no fever, chest or abdominal pain, or urinary symptoms. In the emergency department, she complained of left-sided chest tightness and heaviness, which lasted for a few minutes with associated tachycardia, electrocardiogram (ECG) was consistent with Brugada syndrome type 2. A magnetic resonant imaging (MRI) scan of her head shows a left hemispheric infarct involving the frontoparietal cortex. She was treated for an ischaemic stroke and seizure. She made a good recovery and was discharged home on secondary stroke prevention medication with community physiotherapy. She was followed up in the cardiology, genetics, and stroke outpatient clinics. The occurrence of ECG changes consistent with Brugada syndrome, stroke, and seizure in a young patient with no other risk factors for stroke is rare.

Current gaps in knowledge in inherited arrhythmia syndromes

The 3 most common inherited arrhythmia syndromes-Brugada syndrome, congenital long QT syndrome and catecholaminergic polymorphic ventricular tachycardia-were initially described in the previous century. Since then, research has evolved, which has enabled us to identify patients prior to the onset of potentially life-threatening symptoms. However, there are significant gaps in knowledge that complicate clinical management of these patients today. With this review paper, we aim to highlight the most important knowledge gaps in clinical research of these inherited arrhythmia syndromes.

Anesthesia in patients with Brugada syndrome: two case reports

BACKGROUND

Brugada syndrome is a rare disease. It causes sudden cardiac arrest, which is a serious life-threatening event. Sudden cardiac death mostly results from coronary artery disease. However, patients with Brugada syndrome show normal cardiac anatomy and no evidence of ischemia or electrolyte imbalance. Anesthesia in patients with Brugada syndrome is challenging due to its unpredictable nature, and is worth our attention.

CASE PRESENTATION

We report two cases of Brugada syndrome during anesthesia. In case one, a 31-year-old Filipino laborer was scheduled for laparoscopic appendectomy. The patient denied any preexisting cardiac disease. The preoperative vital signs were stable, with mild fever of 37.9 °C. The operation was smooth. During the emergence period, the patient suffered from sudden onset of ventricular tachycardia. After resuscitation, the cardiac rhythm returned to normal. Later, he was confirmed to have a genetic trait of Brugada syndrome. In case two, a young Taiwanese patient with pre-diagnosed Brugada syndrome underwent an operation. The perioperative precautions were taken to prevent the occurrence of ventricular arrhythmia. The surgery was uneventful.

CONCLUSIONS

Brugada syndrome, although rare, has the highest incidence in South East Asian healthy young males. It brings attention to possible fatal cardiac arrhythmia in this population. Careful preoperative evaluation and perioperative management can help reduce the harmful outcome of the disease and prevent any untoward events.

Unmasking Idiopathic Brugada ECG Pattern: Inducible Type 1 Brugada Pattern in a Young Patient and Clinical Implications

Brugada syndrome is a rare inherited channelopathy associated with an increased risk of ventricular tachycardia and ventricular fibrillation, leading to syncope and sudden cardiac death. We present a case report of a young patient with an inducible type 1 Brugada pattern on an electrocardiogram (ECG), accompanied by a comprehensive literature review. The 19-year-old patient presented with dizziness and exhibited a type 2 Brugada pattern on admission ECG, which converted to a type 1 pattern following an Ajmaline test. Based on the absence of symptoms, inducible arrhythmias, or cardiac events in the patient's history, implantable cardioverter-defibrillator insertion was deemed unnecessary. Genetic testing was recommended, and screening ECGs were advised for the patient's first-degree relatives. The discussion explores the different types of Brugada patterns, their diagnostic significance, and the controversies surrounding risk stratification and management strategies. The case underscores the importance of maintaining clinical suspicion for Brugada syndrome in young patients and tailoring treatment approaches based on individual characteristics and risk factors.

Propofol in ICU Settings: Understanding and Managing Anti-Arrhythmic, Pro-Arrhythmic Effects, and Propofol Infusion Syndrome

Propofol has revolutionized anesthesia and intensive care medicine owing to its favorable pharmacokinetic characteristics, fast onset, and short duration of action. This drug has been shown to be remarkably effective in numerous clinical scenarios. In addition, propofol has maintained an overwhelmingly favorable safety profile; however, it has been associated with both antiarrhythmic and proarrhythmic effects. This review concisely summarizes the dual arrhythmic cardiovascular effects of propofol and a rare but serious complication, propofol infusion syndrome (PRIS). We also discuss the need for careful patient evaluation, compliance with recommended infusion rates, and vigilant monitoring.

Frontier and hotspot evolution in Brugada syndrome: A bibliometric analysis from 2002 to 2022

BACKGROUND

Brugada syndrome (BrS) is a genetic disorder characterized by a typical electrocardiogram pattern and predisposition to arrhythmias and sudden cardiac death. Despite our considerably evolved understanding of BrS, no bibliometrics have been performed in this research field. We aimed to analyze and visualize the characteristics of the scientific outputs, topical evolutions, and research trends of BrS over the past 2 decades using bibliometric analysis.

METHODS

The literature associated with BrS was retrieved from the Science Citation Index Expanded of the Web of Science Core Collection database. Acquired data were then visually analyzed using CiteSpace and VOSviewer.

RESULTS

3042 qualifying records were included in the final analysis. The publication outputs increased over time. The United States was the leading country in the BrS research. The University of Amsterdam (Netherlands) was the most prolific and influential institution. Pedro Brugada, Arthur Wilde, and Charles Antzelevitch exerted notable publication impact and made the most significant contributions in the field of BrS. Heart Rhythm had the highest outputs and Circulation was the most influential journal. Bundle branch block, ST-segment elevation, mechanism, management, right precordial lead, and guideline were the keywords with the strongest citation burst.

CONCLUSION

Research on BrS is prosperous. Keywords and co-citation analysis revealed that the mechanism, diagnosis, risk stratification, and management of BrS were the research hotspots. Besides, the underlying pathophysiology, novel therapies, and personalized risk assessment might be the emerging trends of future research.

A Novel DLG1 Variant in a Family with Brugada Syndrome: Clinical Characteristics and In Silico Analysis

BACKGROUND

Brugada syndrome (BrS) is an inherited primary channelopathy syndrome associated to sudden cardiac death. Overall, variants have been identified in eighteen genes encoding for ion channel subunits and seven genes for regulatory proteins. Recently, a missense variant in DLG1 has been found within a BrS phenotype-positive patient. DLG1 encodes for synapse associated protein 97 (SAP97), a protein characterized by the presence of multiple domains for protein-protein interactions including PDZ domains. In cardiomyocytes, SAP97 interacts with Nav1.5, a PDZ binding motif of SCN5A and others potassium channel subunits.

AIM OF THE STUDY

To characterize the phenotype of an Italian family with BrS syndrome carrying a DLG1 variant.

METHODS

Clinical and genetic investigations were performed. Genetic testing was performed with whole-exome sequencing (WES) using the Illumina platform. According to the standard protocol, a variant found by WES was confirmed in all members of the family by bi-directional capillary Sanger resequencing. The effect of the variant was investigated by using in silico prediction of pathogenicity.

RESULTS

The index case was a 74-year-old man with spontaneous type 1 BrS ECG pattern that experienced syncope and underwent ICD implantation. WES of the index case, performed assuming a dominant mode of inheritance, identified a heterozygous variant, c.1556G>A (p.R519H), in the exon 15 of the DLG1 gene. In the pedigree investigation, 6 out of 12 family members had the variant. Carriers of the gene variant all had BrS ECG type 1 drug induced and showed heterogeneous cardiac phenotypes with two patients experiencing syncope during exercise and fever, respectively. The amino acid residue #519 lies near a PDZ domain and in silico analysis suggested a causal role for the variant. Modelling of the resulting protein structure predicted that the variant disrupts an H-bond and a likelihood of being pathogenic. As a consequence, it is likely that a conformational change affects protein functionality and the modulating role on ion channels.

CONCLUSIONS

A DLG1 gene variant identified was associated with BrS. The variant could modify the formation of multichannel protein complexes, affecting ion channels to specific compartments in cardiomyocytes.

Brugada Syndrome: From Molecular Mechanisms and Genetics to Risk Stratification

Brugada syndrome (BrS) is a rare hereditary arrhythmia disorder, with a distinctive ECG pattern, correlated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD) in young adults. BrS is a complex entity in terms of mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management. The main electrophysiological mechanism of BrS requires further research, with prevailing theories centered on aberrant repolarization, depolarization, and current-load match. Computational modelling, pre-clinical, and clinical research show that BrS molecular anomalies result in excitation wavelength (k) modifications, which eventually increase the risk of arrhythmia. Although a mutation in the SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5) gene was first reported almost two decades ago, BrS is still currently regarded as a Mendelian condition inherited in an autosomal dominant manner with incomplete penetrance, despite the recent developments in the field of genetics and the latest hypothesis of additional inheritance pathways proposing a more complex mode of inheritance. In spite of the extensive use of the next-generation sequencing (NGS) technique with high coverage, genetics remains unexplained in a number of clinically confirmed cases. Except for the SCN5A which encodes the cardiac sodium channel NaV1.5, susceptibility genes remain mostly unidentified. The predominance of cardiac transcription factor loci suggests that transcriptional regulation is essential to the Brugada syndrome's pathogenesis. It appears that BrS is a multifactorial disease, which is influenced by several loci, each of which is affected by the environment. The primary challenge in individuals with a BrS type 1 ECG is to identify those who are at risk for sudden death, researchers propose the use of a multiparametric clinical and instrumental strategy for risk stratification. The aim of this review is to summarize the latest findings addressing the genetic architecture of BrS and to provide novel perspectives into its molecular underpinnings and novel models of risk stratification.

A Case of Brugada Syndrome Masquerading as Acute Coronary Syndrome in a Hispanic Male

Brugada syndrome is an aberrant ST-segment elevation in the right precordial leads. It can progress into sudden cardiac death (SCD) among patients with structurally normal hearts. Most patients are asymptomatic at presentation, but those who develop symptoms can present with syncope due to other arrhythmias such as ventricular tachycardia or fibrillation. Early diagnosis and appropriate management can prevent future complications in patients with a significant family history.

Advances in Ventricular Arrhythmia Ablation for Brugada Syndrome

Three decades have passed since the Brugada syndrome (BrS) clinical entity was introduced in the early 1990s. During the first 2 decades, treatment of patients with BrS was challenging because there were limited treatment options, and an implantable cardioverter-defibrillator was the only choice for high-risk patients with BrS, that is, those who had aborted sudden cardiac death or had previous ventricular fibrillation episodes. In this article, the authors focus on these advances and how to treat patients with BrS with catheter ablation.

Brugada Syndrome as a Major Cause of Sudden Cardiac Death in Asians

Brugada syndrome (BrS) is one of the main inherited arrhythmia syndromes causing ventricular fibrillation (VF) and sudden cardiac death in young to middle-aged men, especially in Asians. The diagnosis of BrS is based on spontaneous or drug-provoked type 1 Brugada electrocardiogram. The current reliable therapy for BrS patients with VF history is the implantation of an implantable cardioverter-defibrillator. As for BrS patients without VF history, how asymptomatic BrS patients should effectively be treated is still uncertain because risk stratification of the BrS is still inadequate. Various parameters and combinations of several parameters have been reported for risk stratification of BrS. The SCN5A gene is believed to be the only gene that is responsible for BrS, and it has been reported to be useful for risk stratification. This review focuses on risk stratification of BrS patients, and focuses specifically on BrS patients of Asian descent.

The "Heart" of COVID-19: Brugada Syndrome and Post-SARS-CoV-2 Virus Cardiac Nursing Care

Coronavirus disease (COVID-19) is an illness that was sudden, unexpected, and global. Primarily a disease of the vascular endothelium, the virus threatens all of core systems, as well as behavioral and mental health, during the acute and long-term phases. Attention is now being given to the identification and care of post-acute sequelae of COVID-19. This article presents the case of a "long hauler" who presented post-cardiac arrest with a history of COVID-19. Diagnosed with Brugada syndrome, his assessment, diagnosis, and care are discussed. In addition, the need for early identification and care for patients with post-COVID-19 symptoms is addressed.

Fever following Covid-19 vaccination in subjects with Brugada syndrome: Incidence and management

BACKGROUND

Fever is a potential side effect of the Covid-19 vaccination. Patients with Brugada syndrome (BrS) have an increased risk of life-threatening arrhythmias when experiencing fever. Prompt treatment with antipyretic drugs is suggested in these patients.

AIM OF THE STUDY

To evaluate the incidence and management of fever within 48 h from Covid-19 vaccination among BrS patients.

METHODS

One hundred sixty-three consecutive patients were enrolled in a prospective registry involving five European hospitals with a dedicated inherited disease ambulatory.

RESULTS

The mean age was 50 ± 14 years and 121 (75%) patients were male. Prevalence of Brugada electrocardiogram (ECG) pattern type-1, -2, and -3 was 32%, 44%, and 24%, respectively. Twenty-eight (17%) patients had an implantable cardioverter-defibrillator (ICD). Fever occurred in 32 (19%) BrS patients after 16 ± 10 h from vaccination, with a peak of body temperature of 37.9° ± 0.5°. Patients with fever were younger (39 ± 13 vs. 48 ± 13 years, p = .04). No additional differences in terms of sex and cardiovascular risk factors were found between patients with fever and not. Twenty-seven (84%) out of 32 patients experienced mild fever and five (16%) moderate fever. Pharmacological treatment with antipyretic drugs was required in 18 (56%) out of 32 patients and was associated with the resolution of symptoms. No patient required hospital admission and no arrhythmic episode was recorded in patients with ICD within 48 h after vaccination. No induced type 1 BrS ECG pattern and new ECG features were found among patients with moderate fever.

CONCLUSION

Fever is a common side effect in BrS patients after the Covid-19 vaccination. Careful evaluation of body temperature and prompt treatment with antipyretic drugs may be needed.

A community-based study on electrocardiographic abnormalities of adult population from South India - findings from a cross sectional survey

Background

There are no data on electrocardiographic (ECG) findings from general population of Indian subcontinent. We analyzed ECG abnormalities of in adults as part of a community survey of prevalence of coronary artery disease and risk factors from South India.

Methods and results

In this cross-sectional study of men and women between the ages 20 to 79 years, ECGs recorded digitally were analyzed using the Minnesota code. Electrocardiograms were analyzed for abnormalities in 4630 participants (women 59.6%). The overall prevalence of ECG abnormalities (39.9%) was higher in men (47.24% vs. 34.9% p <0.0001). QRS axis deviation, first degree AV block, fascicular blocks, incomplete right bundle branch block, sinus bradycardia and ST elevation in the anterior chest leads were markedly higher in men. Sinus tachycardia and low voltage QRS occurred more often in women. The overall prevalence of atrial fibrillation was 0.32% which was markedly lower than the western data. Brugada and early repolarisation patterns occurred in 1.06% and 1.56% respectively, equal in both age groups, but markedly higher in men. Brugada pattern occurred more often than in the west, but much less than the Far East population. Early repolarisation pattern was similar to rest of Asian population, but significantly less than the Caucasian population

Conclusion

In this community-based study, prevalence of major electrocardiographic abnormalities was high. Overall, men had significantly higher ECG abnormalities.

Analysis of a Family with Brugada Syndrome and Sudden Cardiac Death Caused by a Novel Mutation of SCN5A

Background. Brugada syndrome is a hereditary cardiac disease associated with mutations in ion channel genes. The clinical features include ventricular fibrillation, syncope, and sudden cardiac death. A family with Brugada syndrome with sudden cardiac death was analyzed to locate the associated mutation in the SCN5A gene. Methods and Results. Three generations of a Han Chinese family with Brugada syndrome were recruited in the study; their clinical phenotype data were collected and DNA samples extracted from the peripheral blood. Next-generation sequencing was carried out in the proband, and candidate genes and mutations were screened using the full exon capture technique. The family members who participated in the survey were tested for possible mutations using Sanger sequencing. Six family members were diagnosed with Brugada syndrome, including four asymptomatic patients. A newly discovered heterozygous mutation in the proband was located in exon 25 of SCN5A (NM_000335.5) at c.4313dup(p.Trp1439ValfsTer32). Among the surviving family members, only those with a Brugada wave on their electrocardiogram carried the c.4313dup(p.Trp1439ValfsTer32) variant. Bioinformatics prediction revealed that the frameshift of the c.4313dup (p.Trp1439ValfsTer32) mutant led to a coding change of 32 amino acids, followed by a stop codon, resulting in a truncated protein product. Conclusion. The newly discovered mutation site c.4313dup(p.Trp1439ValfsTer32) in exon 25 of SCN5A may be the molecular genetic basis of the family with Brugada syndrome.

Risk stratification of sudden cardiac death in Brugada syndrome: an updated review of literature

Brugada syndrome is a rare but serious inherited heart disease that causes sudden cardiac death by polymorphic ventricular tachycardia or ventricular fibrillation. It is an autosomal dominant genetic disease that usually occurs in patients in their forties with a structurally normal heart. Electrically, it manifests by ST elevation segment ≥ 2 mm of at least one right precordial lead (V1 and/or V2). Stratification of sudden cardiac death in Brugada syndrome is not always easy and constitutes a real challenge for the practitioner. In this review, we will present the current state of knowledge for arrhythmic risk stratification and the prevention of sudden cardiac death that can result from this syndrome.

Brugada Syndrome in Women: What Do We Know After 30 Years?

Brugada syndrome (BrS) was initially described in 1992 by Josep and Pedro Brugada as an arrhythmogenic disease characterized by ST segment elevation in the right precordial leads and increased risk of sudden cardiac death (SCD). Alterations in the SCN5A gene are responsible for approximately 30% of cases of BrS, following an autosomal dominant pattern of inheritance. However, despite its autosomal transmission, sex-related differences are widely accepted. BrS is more prevalent in males than in females (8–10 times), with males having a 5.5-fold higher risk of SCD. There are also differences in clinical presentation, with females being more frequently asymptomatic and older than males at the time of diagnosis. Some factors have been identified that could explain these differences, among which testosterone seems to play an important role. However, only 30% of the available publications on the syndrome include sex-related information. Therefore, current findings on BrS are based on studies conducted mainly in male population, despite the wide acceptance of gender differences. The inclusion of complete clinical and demographic information in future publications would allow a better understanding of the phenotypic variability of BrS in different age and sex groups helping to improve the diagnosis, management and risk management of SCD.

Sudden Cardiac Arrest in the Paediatric Population

Sudden cardiac arrest in the young is a rare event with a range of potential causes including cardiomyopathies, ion channelopathies, and autonomic nervous system dysfunction. Investigations into the cause involve a multidisciplinary team, including cardiologists, geneticists, and psychologists. In addition to a detailed medical history, family history and circumstances surrounding the event are important in determining the cause. Clinical investigations including an electrocardiogram are fundamental in diagnosis and should be interpreted cautiously because some children may have atypical presentations and an evolving phenotype. The potential for misdiagnosis exists that could lead to incorrect long-term management strategies. If an inherited condition is suspected, genetic testing of the patient and cascade screening of family members is recommended with genetic counselling and psychological support. Medical management is left to the treating physician acknowledging that a clear diagnosis cannot be made in approximately half of cases. Secondary prevention implantable defibrillators are widely deployed but can be associated with complications in young patients. A plan for safe return to activity is recommended along with a proper transition of care into adulthood. Broad screening of the general population for arrhythmia syndromes is not recommended; preventative measures include screening paediatric patients for risk factors by their primary care physician. Several milestone events or activities that take place in youth could be used as opportunities to promote safety. Further work into risk stratification of this paediatric population through patient registries and greater awareness of cardiopulmonary resuscitation and automated external defibrillator use in saving lives is warranted.

The Arrhythmogenic Face of COVID-19: Brugada ECG Pattern in SARS-CoV-2 Infection

In 1992, Brugada syndrome (BS) was first described; an often unrecognized cardiac conduction disorder mainly associated with unexplained sudden cardiac arrest and consecutive syncope. Nevertheless, the pathomechanism of BS and sudden cardiac death remains mainly explained. Mutations in the cardiac sodium channels, which cause a reduction or functional loss of these channels, are associated with characteristic electrocardiographic (ECG) abnormalities and malignant arrhythmia. The majority of affected people are previously healthy and unaware of their genetic predisposition for BS and might experience ventricular tachyarrhythmias and cardiac arrest potentially triggered by several factors (e.g., alcohol, sodium channel blockers, psychotropic drugs, and fever). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was firstly identified in Wuhan in early December 2019 and rapidly spread worldwide as coronavirus disease (COVID-19). COVID-19 is typically characterized by a severe inflammatory response, activation of the immune system, and high febrile illness. Due to this condition, symptomatic COVID-19 infection or vaccination might serve as inciting factor for unmasking the Brugada pattern and represents a risk factor for developing proarrhythmic complications. The aim of this narrative review was to detail the association between virus-related issues such as fever, electrolyte disturbance, and inflammatory stress of COVID-19 infection with transient Brugada-like symptoms and ECG-pattern and its susceptibility to proarrhythmogenic episodes.

Brugada Syndrome

Brugada syndrome (BrS) is an "inherited" condition characterized by predisposition to syncope and cardiac arrest, predominantly during sleep. The prevalence is ∼1:2,000, and is more commonly diagnosed in young to middle-aged males, although patient sex does not appear to impact prognosis. Despite the perception of BrS being an inherited arrhythmia syndrome, most cases are not associated with a single causative gene variant. Electrocardiogram (ECG) findings support variable extent of depolarization and repolarization changes, with coved ST-segment elevation ≥2 mm and a negative T-wave in the right precordial leads. These ECG changes are often intermittent, and may be provoked by fever or sodium channel blocker challenge. Growing evidence from cardiac imaging, epicardial ablation, and pathology studies suggests the presence of an epicardial arrhythmic substrate within the right ventricular outflow tract. Risk stratification aims to identify those who are at increased risk of sudden cardiac death, with well-established factors being the presence of spontaneous ECG changes and a history of cardiac arrest or cardiogenic syncope. Current management involves conservative measures in asymptomatic patients, including fever management and drug avoidance. Symptomatic patients typically undergo implantable cardioverter defibrillator insertion, with quinidine and epicardial ablation used for patients with recurrent arrhythmia. This review summarizes our current understanding of BrS and provides clinicians with a practical approach to diagnosis and management.

Using QRS loop descriptors to characterize the risk of sudden cardiac death in patients with structurally normal hearts

The predictive value of non-invasive electrocardiographic examination findings for the risk of sudden cardiac death (SCD) in populations with structurally normal hearts remains unclear. This study aimed to investigate the characteristics of the QRS vectorcardiography of surface electrocardiography in patients with structurally normal hearts who experienced SCD. We consecutively enrolled patients who underwent vectorcardiography between March 2017 and December 2018 in a tertiary referral medical center. These patients didn’t have structural heart diseases, histories of congestive heart failure, or reduced ejection fraction, and they were classified into SCD (with aborted SCD history and cerebral performance category score of 1) and control groups (with an intervention for atrioventricular node reentrant tachycardia and without SCD history). A total of 162 patients (mean age, 54.3±18.1 years; men, 75.9%), including 59 in the SCD group and 103 in the control group, underwent propensity analysis. The baseline demographic variables, underlying diseases, QRS loop descriptors (the percentage of the loop area, loop dispersion, and inter-lead QRS dispersion), and other electrocardiographic parameters were compared between the two groups. In the univariate and multivariate analyses, a smaller percentage of the loop area (odds ratio, 0.0003; 95% confidence interval, 0.00–0.02; p<0.001), more significant V4-5 dispersion (odds ratio, 1.04; 95% confidence interval, 1.02–1.07; p = 0.002), and longer QRS duration (odds ratio, 1.05; 95% confidence interval, 1.00–1.10; p = 0.04) were associated with SCD. In conclusion, the QRS loop descriptors of surface electrocardiography could be used as non-invasive markers to identify patients experiencing aborted SCD from a healthy population. A decreased percentage of loop area and elevated V4-5 QRS dispersion values assessed using vectorcardiography were associated with an increased risk of SCD in patients with structurally normal hearts.

J wave syndromes in patients with spinal and bulbar muscular atrophy

BACKGROUND

Males with X-linked recessive spinobulbar muscular atrophy (SBMA) are reported to die suddenly and a Brugada electrocardiography (ECG) pattern may be present. A hallmark of this pattern is the presence of ST segment elevations in right precordial leads associated with an increased risk of sudden cardiac death.

OBJECTIVE

We aimed to detect subtle myocardial abnormalities using ECG and cardiovascular magnetic resonance imaging (CMR) in patients with SBMA.

METHODS

30 SBMA patients (55.7 ± 11.9 years) and 11 healthy male controls underwent 12-lead ECGs were recorded using conventional and modified chest leads. CMR included feature-tracking strain analysis, late gadolinium enhancement and native T1 and T2 mapping.

RESULTS

Testosterone levels were increased in 6/29 patients. Abnormal ECGs were recorded in 70%, consisting of a Brugada ECG pattern, early repolarization or fragmented QRS. Despite normal left ventricular ejection fraction (66 ± 5%), SBMA patients exhibited more often left ventricular hypertrophy as compared to controls (34.5% vs 20%). End-diastolic volumes were smaller in SBMA patients (left ventricular volume index 61.7 ± 14.7 ml/m² vs. 79.1 ± 15.5 ml/m²; right ventricular volume index 64.4 ± 16.4 ml/m² vs. 75.3 ± 17.5 ml/m²). Tissue characterization with T1-mapping revealed diffuse myocardial fibrosis in SBMA patients (73.9% vs. 9.1%, device-specific threshold for T1: 1030 ms).

CONCLUSION

SBMA patients show abnormal ECGs and structural abnormalities, which may explain an increased risk of sudden death. These findings underline the importance of ECG screening, measurement of testosterone levels and potentially CMR imaging to assess cardiac risk factors.

Longitudinal Electrocardiographic Assessment in the Brugada Syndrome

Background

The type 1 electrocardiographic (ECG) pattern diagnostic of Brugada syndrome (BrS) can be dynamic. Limited studies have rigorously evaluated the temporal stability of the Brugada ECG pattern.

Objective

We sought to evaluate fluctuations of the Brugada pattern in serial resting ECGs from BrS patients managed within a large health care system.

Methods

In our cohort of BrS patients with at least 2 standard, resting ECGs recorded on separate clinical encounters, we evaluated serial changes in the Brugada pattern and categorized patients into 1 of 3 groups: dynamic was defined as the presence of both type 1 and non–type 1 patterns in available ECGs; the provoked-only group was defined as having a non–type 1 Brugada pattern across resting ECGs; and the persistent group was defined as having a type 1 pattern on all ECGs. We also evaluated the clinical risk in this cohort according to the Shanghai risk score.

Results

In 72 patients with BrS (mean age 46 ± 15 years, 69% male), 828 standard, resting ECGs were recorded over a median duration of 30.2 (interquartile range 6.3–68.1) months. The dynamic group comprised 50 (69% of the cohort) patients, the provoked-only group consisted of 17 patients (24% of the cohort), and the persistent group included 5 patients. No significant differences were detected in the total number of ECGs evaluated during the follow-up period between any of the groups. Only sinus node dysfunction and a prior cardiac arrest were associated with the persistent type 1 group. The majority of patients had a low annualized risk of lethal arrhythmic events.

Conclusion

Most BrS patients have a dynamic Brugada pattern noted on longitudinal, resting ECGs. Expert consensus statements should provide clarity on the frequency of obtaining resting ECGs in patients suspected of having BrS during follow-up.

Pyrexia Unmasking Brugada Syndrome: A Literature Review

Brugada syndrome (BrS) is an inherited arrhythmia syndrome in which asymptomatic patients tend to develop fatal arrhythmias leading to sudden cardiac death (SCD) in asymptomatic or undiagnosed cases. This review tries to shed light on pyrexia being one of the triggers to cause SCD secondary to fatal arrhythmias in patients of BrS. Pyrexia, electrolyte imbalance, alcohol intake, and drugs are common triggering factors for fatal arrhythmias in patients with BrS. Most patients are asymptomatic, while the most common form of presentation that brings the patient under medical attention is syncope or SCD. Hence, patients, especially young, who present with syncope or aborted episode of SCD with typical EKG patterns, should undergo further workup. It is essential to educate patients about the condition, possible triggers, and the importance of refraining them.

Brugada syndrome: should we be screening patients before prescribing psychotropic medication?

Brugada syndrome (BrS) presents with a characteristic electrocardiogram (ECG) and is associated with sudden cardiac death. Until now, prolongation of QTc interval and its association with Torsade de Pointe and possible fatal arrhythmia have been the focus of routine baseline ECGs before prescribing psychotropic medication. A semi-systematic literature review was conducted using PubMed. The terms 'Brugada', 'Brugada Syndrome' AND 'psychotropic' 'antipsychotic' 'antidepressant' 'mood stabilisers' 'clozapine' 'Tricyclic Antidepressants' 'Lithium' were searched. From a search that delivered over 200 articles, 82 articles were included. Those that included details around causative medication, doses of medication and where clear timeline on drug cause were included. Where clarification was needed, the manufacturer of the medication was contacted directly. Psychotropic medication can be associated with BrS, Brugada phenocopy or unmasking of BrS, in overdose or in normal doses. Our results include a table summarising a number of psychotropic overdoses that led to BrS unmasking. Routine screening for BrS in patients before prescribing psychotropic medication is a natural extension of the baseline ECG currently routinely done to rule out QTc prolongation. Psychiatrists need to invest in ensuring better skills in interpreting ECGs and work closer with cardiologists in interpreting ECGs.

Why Is Only Type 1 Electrocardiogram Diagnostic of Brugada Syndrome? Mechanistic Insights From Computer Modeling

BACKGROUND

Three types of characteristic ST-segment elevation are associated with Brugada syndrome but only type 1 is diagnostic. Why only type 1 ECG is diagnostic remains unanswered.

METHODS

Computer simulations were performed in single cells, 1-dimensional cables, and 2-dimensional tissues to investigate the effects of the peak and late components of the transient outward potassium current (Ito), sodium current, and L-type calcium current (ICa,L) as well as other potassium currents on the genesis of ECG morphologies and phase 2 reentry (P2R).

RESULTS

Although a sufficiently large peak Ito was required to result in the type 1 ECG pattern and P2R, increasing the late component of Ito converted type 1 ECG to type 2 ECG and suppressed P2R. Increasing the peak Ito promoted spiral wave breakup, potentiating the transition from tachycardia to fibrillation, but increasing the late Ito prevented spiral wave breakup by flattening the action potential duration restitution and preventing P2R. A sufficiently large ICa,L conductance was needed for P2R to occur, but once above the critical conductance, blocking ICa,L promoted P2R. However, selectively blocking the window and late components of ICa,L suppressed P2R, countering the effect of the late Ito. Blocking either the peak or late components of sodium current promoted P2R, with the late sodium current blockade having the larger effect. As expected, increasing other potassium currents potentiated P2R, with ATP-sensitive potassium current exhibiting a larger effect than rapid and slow component of the delayed rectifier potassium current.

CONCLUSIONS

The peak Ito promotes type 1 ECG and P2R, whereas the late Ito converts type 1 ECG to type 2 ECG and suppresses P2R. Blocking the peak ICa,L and either the peak or the late sodium current promotes P2R, whereas blocking the window and late ICa,L suppresses P2R. These results provide important insights into the mechanisms of arrhythmogenesis and potential therapeutic targets for treatment of Brugada syndrome. Graphic Abstract: A graphic abstract is available for this article.

Brugada syndrome - minimizing overdiagnosis and over treatment in children

PURPOSE OF REVIEW

Is to summarise the new contributions toward the understanding of the broad spectrum of manifestations of Brugada syndrome (BrS) during the first years of life. The review encompasses the screening of the asymptomatic patient referred due to family history in one extreme of the spectrum, and also the rare child with early clinical expression of the disease on the opposite side.

RECENT FINDINGS

Involve specific features of pediatric BrS including the risk related to a positive family history of sudden cardiac death, the risk of presenting with syncope and the multiple diagnostic challenges of the disease. We included some of the most controversial aspects of the diagnosis and risk stratification, encompassing noninvasive studies (Holter monitors, exercise test, implantable loop recorders, and provocative tests), as well as invasive stratification during the first years of life. Finally, the role and concerns of genetic testing in this age group are commented upon.

SUMMARY

The main key to minimize overdiagnosis and overtreatment in the young population with a personal and/or family diagnosis of BrS is to perform a systematic but also individualized assessment. Appropriate diagnostic guidelines need to be created and age-specific risk stratification algorithms built for the young patient both with suspected and confirmed BrS.

Ventricular fibrillation arrest due to Brugada syndrome in a coronavirus disease 2019 patient with negative procainamide challenge: a case report

Background

Pharmacologic challenge test is often used to diagnose Brugada syndrome (BrS) when spontaneous electrocardiograms (ECG) do not show type I Brugada pattern but reported sensitivity varies. The role of the exercise stress test in diagnosing Brugada syndrome is not well-established.

Case summary

A patient had a type I Brugada pattern ECG during the recovery phase of exercise stress test but had a negative procainamide challenge test. He had a loop recorder implanted and later survived a ventricular fibrillation (VF) arrest provoked by coronavirus disease 2019 (COVID-19). Electrocardiogram on arrival showed type 1 Brugada pattern. He was discharged after implantable cardioverter-defibrillator implantation. He later underwent genetic testing and was found to be heterozygous for c.844C>G (p.Arg282Gly) mutation in the SCN5A gene.

Discussion

Type 1 Brugada pattern ECG may be unmasked by ST-segment augmentation during recovery from exercise. Exercise stress test may play a role in the diagnosis of Brugada syndrome when suspicion for Brugada syndrome remains after a negative procainamide challenge test or if the patient has exercise-related symptoms. COVID-19 can unmask BrS and trigger a VF cardiac arrest.

Multisite conduction block in the epicardial substrate of Brugada syndrome

BACKGROUND

The Brugada pattern manifests as a spontaneous variability of the electrocardiographic marker, suggesting a variability of the underlying electrical substrate.

OBJECTIVE

The purpose of this study was to investigate the response of the epicardial substrate of Brugada syndrome (BrS) to programmed ventricular stimulation and to Na blocker infusion.

METHODS

We investigated 6 patients (all male; mean age 54 ± 14 years) with BrS and recurrent ventricular fibrillation. Five had no type 1 BrS electrocardiogram pattern at admission. They underwent combined epicardial-endocardial mapping using multielectrode catheters. Changes in epicardial electrograms were evaluated during single endocardial extrastimulation and after low-dose ajmaline infusion (0.5 mg/kg in 5 minutes).

RESULTS

All patients had a region in the anterior epicardial right ventricle with prolonged multicomponent electrograms. Single extrastimulation prolonged late epicardial components by 59 ± 31 ms and in 4 patients abolished epicardial components at some sites, without reactivation by surrounding activated sites. These localized blocks occurred at an initial coupling interval of 335 ± 58 ms and then expanded to other sites, being observed in up to 40% of epicardial sites. Ajmaline infusion prolonged electrogram duration in all and produced localized blocks in 62% of sites in the same patients as during extrastimulation. Epicardial conduction recovery after ajmaline occurred intermittently and at discontinuous sites and produced beat-to-beat changes in local repolarization, resulting in an area of marked electrical disparity. These changes were consistent with models based on microstructural alterations under critical propagation conditions.

CONCLUSION

In BrS, localized functional conduction blocks occur at multiple epicardial sites and with variable patterns, without being reactivated from the surrounding sites.

The BrAID study protocol: integration of machine learning and transcriptomics for brugada syndrome recognition

BACKGROUND

Type 1 Brugada syndrome (BrS) is a hereditary arrhythmogenic disease showing peculiar electrocardiographic (ECG) patterns, characterized by ST-segment elevation in the right precordial leads, and risk of Sudden Cardiac Death (SCD). Furthermore, although various ECG patterns are described in the literature, different individual ECG may show high-grade variability, making the diagnosis problematic. The study aims to develop an innovative system for an accurate diagnosis of Type 1 BrS based on ECG pattern recognition by Machine Learning (ML) models and blood markers analysis trough transcriptomic techniques.

METHODS

The study is structured in 3 parts: (a) a retrospective study, with the first cohort of 300 anonymized ECG obtained in already diagnosed Type 1 BrS (75 spontaneous, 150 suspected) and 75 from control patients, which will be processed by ML analysis for pattern recognition; (b) a prospective study, with a cohort of 11 patients with spontaneous Type 1 BrS, 11 with drug-induced Type 1 BrS, 11 suspected BrS but negative to Na + channel blockers administration, and 11 controls, enrolled for ECG ML analysis and blood collection for transcriptomics and microvesicles analysis; (c) a validation study, with the third cohort of 100 patients (35 spontaneous and 35 drug-induced BrS, 30 controls) for ML algorithm and biomarkers testing.

DISCUSSION

The BrAID system will help clinicians improve the diagnosis of Type 1 BrS by using multiple information, reducing the time between ECG recording and final diagnosis, integrating clinical, biochemical and ECG information thus favoring a more effective use of available resources. Trial registration Clinical Trial.gov, NCT04641585. Registered 17 November 2020, https://clinicaltrials.gov/ct2/show/NCT04641585.

Modeling genetic cardiac channelopathies using induced pluripotent stem cells - Status quo from an electrophysiological perspective

Long QT syndrome (LQTS), Brugada syndrome (BrS), and catecholaminergic polymorphic ventricular tachycardia (CPVT) are genetic diseases of the heart caused by mutations in specific cardiac ion channels and are characterized by paroxysmal arrhythmias, which can deteriorate into ventricular fibrillation. In LQTS3 and BrS different mutations in the SCN5A gene lead to a gain-or a loss-of-function of the voltage-gated sodium channel Nav1.5, respectively. Although sharing the same gene mutation, these syndromes are characterized by different clinical manifestations and functional perturbations and in some cases even present an overlapping clinical phenotype. Several studies have shown that Na⁺ current abnormalities in LQTS3 and BrS can also cause Ca²⁺-signaling aberrancies in cardiomyocytes (CMs). Abnormal Ca²⁺ homeostasis is also the main feature of CPVT which is mostly caused by heterozygous mutations in the RyR2 gene. Large numbers of disease-causing mutations were identified in RyR2 and SCN5A but it is not clear how different variants in the SCN5A gene produce different clinical syndromes and if in CPVT Ca²⁺ abnormalities and drug sensitivities vary depending on the mutation site in the RyR2. These questions can now be addressed by using patient-specific in vitro models of these diseases based on induced pluripotent stem cells (iPSCs). In this review, we summarize different insights gained from these models with a focus on electrophysiological perturbations caused by different ion channel mutations and discuss how will this knowledge help develop better stratification and more efficient personalized therapies for these patients.

Impact of Dietary Factors on Brugada Syndrome and Long QT Syndrome

A healthy regime is fundamental for the prevention of cardiovascular diseases (CVD). In inherited channelopathies, such as Brugada syndrome (BrS) and Long QT syndrome (LQTS), unfortunately, sudden cardiac death could be the first sign for patients affected by these syndromes. Several known factors are used to stratify the risk of developing cardiac arrhythmias, although none are determinative. The risk factors can be affected by adjusting lifestyle habits, such as a particular diet, impacting the risk of arrhythmogenic events and mortality. To date, the importance of understanding the relationship between diet and inherited channelopathies has been underrated. Therefore, we describe herein the effects of dietary factors on the development of arrhythmia in patients affected by BrS and LQTS. Modifying the diet might not be enough to fully prevent arrhythmias, but it can help lower the risk.