Clinical Management of Brugada Syndrome: Commentary From the Experts

Although there is consensus on the management of patients with Brugada Syndrome with high risk for sudden cardiac arrest, asymptomatic or intermediate-risk patients present clinical management challenges. This document explores the management opinions of experts throughout the world for patients with Brugada Syndrome who do not fit guideline recommendations. Four real-world clinical scenarios were presented with commentary from small expert groups for each case. All authors voted on case-specific questions to evaluate the level of consensus among the entire group in nuanced diagnostic and management decisions relevant to each case. Points of agreement, points of controversy, and gaps in knowledge are highlighted.

Successful Therapeutic Hypothermia in a Patient with Drug-Induced J Waves and Cardiac Arrest: A Case Report

A 50-year-old man was admitted to our hospital with hypotension and bradycardia after receiving high doses of atenolol, amlodipine, and etizolam. He had a drug-induced J wave on electrocardiography and subsequently underwent cardiac arrest. The patient was successfully rescued by venoarterial extracorporeal membrane oxygenation (VA-ECMO) and a good neurological outcome was achieved with therapeutic hypothermia (TH). In patients with J waves, TH is thought to increase the J waves and cause fatal arrhythmias, but in this case, rapid cooling with VA-ECMO allowed the patient to successfully complete TH.

Procainamide-Provoked Brugada Pattern in a Patient Presenting with New-Onset Atrial Fibrillation or Flutter: When Does it Matter?

BACKGROUND

Brugada syndrome (BrS) is an inherited disease that can lead to sudden cardiac death. Medications, such as antidysrhythmics, and fevers can unmask or induce the Brugada pattern on an electrocardiogram (ECG). This case report highlights a patient who developed drug-induced Brugada type I pattern after a procainamide infusion for the treatment of new-onset atrial fibrillation (AF) or flutter and discusses the implications for this incidental but potentially lethal finding.

CASE REPORT

We report a case of a young man who presented to the emergency department (ED) with new-onset AF with rapid ventricular response that began within 12 h of presentation. ED treatments included a crystalloid IV fluid bolus, diltiazem pushes, synchronized electrical cardioversion, and a procainamide infusion. After the procainamide infusion, the patient developed ECG findings consistent with Brugada pattern. Both the AF and Brugada pattern resolved spontaneously within 24 h. The patient was discharged without implantable cardioverter defibrillator placement due to presumed isolated procainamide-induced Brugada pattern and lack of concerning features, such as inducible dysrhythmia during electrophysiology study, family history of sudden death, and history of syncope. The patient was counseled to follow-up with genetics and avoid BrS-inducing medications. WHY SHOULD AN EMERGENCY PHYSICIANS BE AWARE OF THIS?: Procainamide, an option for the treatment of AF in the ED, can provoke Brugada pattern. If encountered, it is important to recall that some patients may not be diagnosed with BrS if determined to be low risk according to the Shanghai criteria. All patients should be referred to cardiology for further evaluation.

Severity of Brugada syndrome disease manifestation and risk of new-onset depression or anxiety: a Danish nationwide study

AIMS

Reduced psychological health is associated with adverse patient outcomes and higher mortality. We aimed to examine if a Brugada syndrome (BrS) diagnosis and symptomatic disease presentation were associated with an increased risk of new-onset depression or anxiety and all-cause mortality.

METHODS AND RESULTS

All Danish patients diagnosed with BrS (2006-2018) with no history of psychiatric disease and available for ≥6 months follow-up were identified using nationwide registries and followed for up to 5 years after diagnosis. The development of clinical depression or anxiety was evaluated using the prescription of medication and diagnosis codes. Factors associated with developing new-onset depression or anxiety were determined using a multivariate Cox proportional hazards regression model. Disease manifestation was categorized as symptomatic (aborted cardiac arrest, ventricular tachycardia, or syncope) or asymptomatic/unspecified at diagnosis. A total of 223 patients with BrS and no history of psychiatric disease were identified (72.6% male, median age at diagnosis 46 years, 45.3% symptomatic). Of these, 15.7% (35/223) developed new-onset depression or anxiety after BrS diagnosis (median follow-up 5.0 years). A greater proportion of symptomatic patients developed new-onset depression or anxiety compared with asymptomatic patients [21/101 (20.8%) and 14/122 (11.5%), respectively, P = 0.08]. Symptomatic disease presentation (HR 3.43, 1.46-8.05) and older age (lower vs. upper tertile: HR 4.41, 1.42-13.63) were significantly associated with new-onset depression or anxiety. All-cause mortality in this group of patients treated according to guidelines was low (n = 4, 1.8%); however, 3/4 developed depression or anxiety before death.

CONCLUSION

Approximately, one-sixth of patients with BrS developed new-onset depression or anxiety following a diagnosis of BrS. Symptomatic BrS disease manifestation was significantly associated with new-onset depression or anxiety.

Delayed depolarization and histologic abnormalities underlie the Brugada syndrome

Brugada syndrome (BrS) is a controversial disease whose pathophysiology is still far from being fully understood. Unlike other cardiological disorders, a definite etiology has not yet been established so that it could be summarized under two main chapters: "functional" or "organic", "repolarization" or "depolarization" disorder. Despite initial descriptions leaned towards the organic substrate and delayed depolarization features, functional and repolarization theories have attracted most of the Cardiological attention for many years. Data from electrocardiography, endocavitary tracings, electroanatomic mapping and histopathology, however, demonstrated that BrS is mainly characterized by structural myocardial changes mostly at the right ventricular outflow tract (RVOT), but also at the right ventricle (RV) and by delayed conduction at the same sites. Conduction disorders at different levels may also be present and identify patients at high risk for major arrhythmic events. The aim of the present review is to provide the current state of art of the pathophysiology of BrS, focusing on electro-vectorcardiography and electrophysiological features, histopathology, echocardiography, and cardiac magnetic resonance imaging (CMRI).

Brugada phenocopy secondary to hyperkalemia and hyponatremia in primary adrenal insufficiency

Introduction

The Brugada phenocopy represents electrocardiogram (ECG) changes nearly identical to the Brugada syndrome but without the congenital abnormality associated with lethal arrhythmias and normalizes with treatment of the underlying etiology. This case highlights the Brugada phenocopy in the setting of moderate hyperkalemia and severe hyponatremia from adrenal insufficiency that resolves with treatment of the underlying metabolic disturbance.

Case Report

A 26‐year‐old man with no prior medical history presented to the emergency department with syncope, and his ECG revealed a Brugada‐like pattern. The patient was found to have significant metabolic derangements, including severe hyponatremia (94 mEq/L), moderate hyperkalemia (6.1 mEq/L), severe hypochloremia (<60 mEq/L), acute kidney injury, and rhabdomyolysis. The patient was diagnosed with primary adrenal insufficiency, and electrolyte correction led to resolution of the Brugada phenocopy.

Conclusion

The Brugada phenocopy on ECG can occur with severe hyponatremia and moderate hyperkalemia and quickly resolves with electrolyte correction.

Long-Term Outcomes of Pulmonary Vein Isolation in Patients With Brugada Syndrome and Paroxysmal Atrial Fibrillation

Background Pharmacological treatment of atrial fibrillation (AF) in the setting of Brugada syndrome (BrS) is challenging. In addition, patients with BrS with an implantable cardioverter-defibrillator (ICD) might experience inappropriate shocks for fast AF. Long-term outcome of pulmonary vein isolation in BrS has not been well established yet, and it is still unclear whether pulmonary vein triggers are the only pathophysiological mechanism of AF in BrS. The aim of the study is to assess the long-term outcomes in patients with BrS undergoing pulmonary vein isolation for paroxysmal AF compared with a matched cohort of patients without BrS. Methods and Results Sixty patients with BrS undergoing pulmonary vein isolation with cryoballoon catheter ablation for paroxysmal AF were matched with 60 patients without BrS, who underwent the same procedure. After a mean follow-up of 58.2±31.7 months, freedom from atrial tachyarrhythmias was achieved in 61.7% in the BrS group and in 78.3% in the non-BrS group (log-rank P=0.047). In particular, freedom from AF was 76.7% in the first group and in 83.3% in the second (P=0.27), while freedom from atrial tachycardia/atrial flutter was 85% and 95% (P=0.057). In the BrS group, 29 patients (48.3%) had an ICD and 8 (27.6%) had a previous ICD-inappropriate shock for fast AF. In the BrS cohort, ICD-inappropriate interventions for AF were significantly reduced after ablation (3.4% versus 27.6%; P=0.01). Conclusions Pulmonary vein isolation in patients with BrS was associated with higher rate of arrhythmic recurrence. Despite this, catheter ablation significantly reduced inappropriate ICD interventions in BrS patients and can be considered a therapeutic strategy to prevent inappropriate device therapies.

The Unmasking Effect: Propofol-Induced Brugada Pattern in a Critically Ill Patient

Brugada syndrome is a known cause of dysrhythmias and sudden cardiac death. It is linked to mutations in myocardial sodium channel leading to hyperexcitable cardiac myocytes. The use of this sedative has been linked to the development of inducible Brugada via blockade of sodium currents in cardiac myocytes. Although propofol is usually avoided in patients with known Brugada syndrome, some patients might have undiagnosed Brugada syndrome and thus are at risk for complications. We present a case of propofol induced Brugada in a critically ill patient.

A Rare yet Morbid Complication of Cocaine Use: Brugada Type 1 on Electrocardiogram

Cocaine is considered a leading non-opioid cause of drug overdose in the US. It acts as a sympathomimetic and increases the amount of catecholamines, thereby increasing the risk of ventricular irritability and resultant arrhythmias. Its sodium (Na) channel blockage is the principal mechanism behind the Brugada pattern on an electrocardiogram (ECG), which is often transient but is indistinguishable from that of Brugada syndrome, the autosomal dominant channelopathy.

We are presenting a case of a 32-year-old male with a history of cocaine and nicotine abuse, who sought medical attention for sudden-onset palpitations and pressure-like chest pain after having snorted an impressive amount of cocaine. His ECG depicted a classical Brugada pattern with ST-elevation with T inversion in V1; however, previous ECGs were normal without ST changes, signifying the Brugada pattern unmasked by cocaine use. Other investigations including stress tests and nuclear imaging were equivocal. His symptoms as well as the ECG pattern reverted to baseline signifying the presence of Brugada phenotype in the absence of channelopathy.

Hence, as a sodium channel blocker, cocaine may unmask latent Brugada syndrome in asymptomatic patients without a family history. Recognizing Brugada syndrome on ECG is vital to avoid misdiagnosis and mistreatment of the patient with and without a genetic predisposition.

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.

Cardiovascular effects of doping substances, commonly prescribed medications and ergogenic aids in relation to sports: a position statement of the sport cardiology and exercise nucleus of the European Association of Preventive Cardiology

The use of substances and medications with potential cardiovascular effects among those practicing sports and physical activity has progressively increased in recent years. This is also connected to the promotion of physical activity and exercise as core aspects of a healthy lifestyle, which has led also to an increase in sport participation across all ages. In this context, three main users' categories can be identified, (i) professional and amateur athletes using substances to enhance their performance, (ii) people with chronic conditions, which include physical activity and sport in their therapeutic plan, in association with prescribed medications, and (iii) athletes and young individuals using supplements or ergogenic aids to integrate their diet or obtaining a cognitive enhancement effect. All the substances used for these purposes have been reported to have side effects, among whom the cardiovascular consequences are the most dangerous and could lead to cardiac events. The cardiovascular effect depends on the type of substance, the amount, the duration of use, and the individual response to the substances, considering the great variability in responses. This Position Paper reviews the recent literature and represents an update to the previously published Position Paper published in 2006. The objective is to inform physicians, athletes, coaches, and those participating in sport for a health enhancement purpose, about the adverse cardiovascular effects of doping substances, commonly prescribed medications and ergogenic aids, when associated with sport and exercise.

Brugada syndrome

Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome that causes a heightened risk for ventricular tachyarrhythmias and sudden cardiac death. BrS is characterised by a coved ST-segment elevation in right precordial leads. The prevalence is estimated to range between 1 in 5,000 to 1 in 2,000 in different populations, with the highest being in Southeast Asia and in males. More than 18 genes associated with BrS have been discovered and recent evidence has suggested a complex polygenic mode of inheritance with multiple common and rare genetic variants acting in concert to produce the BrS phenotype. Diagnosis of BrS in patients currently relies on presentation with a type-1 Brugada pattern on ECG either spontaneously or following a drug provocation test using a sodium channel blocker. Risk assessment in patients diagnosed with BrS is controversial, especially with regard to the predictive value of programmed electrical stimulation and novel ECG parameters, such as QRS fragmentation. The first line of BrS therapy remains an implantable cardioverter defibrillator (ICD), although radiofrequency catheter ablation has been shown to be an effective option in patients with contraindications for an ICD. True BrS can be unmasked on ECG in susceptible individuals by monitoring factors such as fever, and this has been recently evident in several patients infected with the 2019 novel coronavirus (COVID-19). Aggressive antipyretic therapy and regular ECG monitoring until fever resolves are current recommendations to help reduce the arrhythmic risk in these COVID-19 patients. In this review, we summarise the current knowledge on the epidemiology, pathophysiology, genetics, clinical diagnosis, risk stratification and treatment of patients with BrS, with special emphasis on COVID-19 comorbidity.

[A case of cardiac arrest due to the appearance of Brugada-type electrocardiogram during epilepsy treatment]

The appearance of arrhythmias in epilepsy practice can lead to sudden death. This time, we experienced a case of cardiac arrest caused by lethal arrhythmia and resuscitation, and captured changes in the electrocardiogram over time from outpatient, before and after sudden change, after resuscitation, to convalescent period. QT prolongation and Brugada-type waveforms were confirmed in the changes over time in the electrocardiogram. Focusing on the importance of recognizing the pharmacological and pharmacokinetic interactions with Na channel blockers and psychotropic drugs that may induce electrocardiographic changes, we emphasized the importance of electrocardiogram in epilepsy treatment.

Evaluating the Use of Genetics in Brugada Syndrome Risk Stratification

The evolution of the current dogma surrounding Brugada syndrome (BrS) has led to a significant debate about the real usefulness of genetic testing in this syndrome. Since BrS is defined by a particular electrocardiogram (ECG) pattern, after ruling out certain possible causes, this disease has come to be defined more for what it is not than for what it is. Extensive research is required to understand the effects of specific individual variants, including modifiers, rather than necessarily grouping together, for example, “all SCN5A variants” when trying to determine genotype-phenotype relationships, because not all variants within a particular gene act similarly. Genetic testing, including whole exome or whole genome testing, and family segregation analysis should always be performed when possible, as this is necessary to advance our understanding of the genetics of this condition. All considered, BrS should no longer be considered a pure autosomal dominant disorder, but an oligogenic condition. Less common patterns of inheritance, such as recessive, X–linked, or mitochondrial may exist. Genetic testing, in our opinion, should not be used for diagnostic purposes. However, variants in SCN5A can have a prognostic value. Patients should be diagnosed and treated per the current guidelines, after an arrhythmologic examination, based on the presence of the specific BrS ECG pattern. The genotype characterization should come in a second stage, particularly in order to guide the familial diagnostic work-up. In families in which an SCN5A pathogenic variant is found, genetic testing could possibly contribute to the prognostic risk stratification.

Cocaine and Cardiotoxicity: A Literature Review

Long-term cocaine use, as well as acute cocaine use, is associated with adverse cardiovascular consequences, including arrhythmias, angina, myocardial infarction, heart failure, and other conditions. Over the long term, cocaine can result in structural changes to the heart such as increased left-ventricular mass and decreased left-ventricular end-diastolic volume. Patients arriving with cocaine-associated cardiovascular complaints may not be forthcoming about their cocaine or polysubstance abuse or may be unresponsive. The role of beta-blockers, a first-line treatment for many forms of heart disease, is controversial in this population. Cocaine is a powerful sympathomimetic agent, and it was thought that beta-blockade would result in unopposed alpha-adrenergic stimulation and adverse consequences. A number of small, single-center, retrospective and observational studies suggest that beta-blockers may be safe, effective, and beneficial in this population. Further study is needed to clarify the role of beta-blockers in this population. 

Transient Brugada Pattern Induced by Loperamide Abuse

Brugada syndrome (BrS) is classically a malignant, genetically determined, arrhythmic syndrome manifesting as syncope or sudden cardiac death (SCD) in individuals with structurally normal hearts. An exceedingly rare cause of an induced electrocardiogram (ECG) pattern mimicking BrS is secondary to loperamide abuse. The following case describes the onset of a transient Brugada pattern secondary to loperamide abuse in a young healthy male.

Suspected Brugada Phenocopy Secondary to Coronary Slow Flow

Brugada syndrome (BrS) is a genetic condition that accentuates the risk of potentially lethal ventricular arrhythmias and sudden cardiac death (SCD) in a structurally normal heart. The Brugada electrocardiographic pattern may manifest separately from the syndrome—this clinical scenario has been described as Brugada phenocopy (BrP). Many etiologies of BrP have been reported, but it has not yet been reported as a result of coronary slow flow (CSF) phenomenon. This case report highlights a suspected coronary slow flow-associated Brugada type 1 electrocardiographic pattern, which subsequently normalized following the institution of guideline-directed medical therapy for acute coronary syndrome.

Present Status of Brugada Syndrome: JACC State-of-the-Art Review

The Brugada syndrome is an inherited disorder associated with risk of ventricular fibrillation and sudden cardiac death in a structurally normal heart. Diagnosis is based on a characteristic electrocardiographic pattern (coved type ST-segment elevation ≥2 mm followed by a negative T-wave in ≥1 of the right precordial leads V₁ to V₂), observed either spontaneously or during a sodium-channel blocker test. The prevalence varies among regions and ethnicities, affecting mostly males. The risk stratification and management of patients, principally asymptomatic, still remains challenging. The current main therapy is an implantable cardioverter-defibrillator, but radiofrequency catheter ablation has been recently reported as an effective new treatment. Since its first description in 1992, continuous achievements have expanded our understanding of the genetics basis and electrophysiological mechanisms underlying the disease. Currently, despite several genes identified, SCN5A has attracted most attention, and in approximately 30% of patients, a genetic variant may be implicated in causation after a comprehensive analysis.

Epinephrine Administered for Anaphylaxis Unmasking a Type 1 Brugada Pattern on Electrocardiogram

BACKGROUND

Brugada pattern on electrocardiography (ECG) can manifest as type 1 (coved pattern) and type 2 (saddleback pattern). Brugada syndrome represents an ECG with Brugada pattern in a patient with symptoms or clinical factors, including syncope, cardiac arrest, ventricular dysrhythmias, and family history. Brugada syndrome is caused by a genetic channelopathy, but the Brugada pattern may be drug-induced. Epinephrine-induced Brugada pattern has not been reported previously.

CASE REPORT

A 63-year-old man developed anaphylaxis secondary to a bee sting, had a transient loss of consciousness, and self-administered intramuscular epinephrine. He subsequently presented to the emergency department and was found to have a type 1 Brugada pattern on ECG that resolved during observation. A historic ECG was reviewed that demonstrated a baseline type 2 Brugada pattern. His anaphylaxis was managed with steroids and antihistamines. He was observed without subsequent dysrhythmic events on telemetry or any further symptoms. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The differential diagnosis for syncope includes dysrhythmia, such as Brugada syndrome. Among other possible drugs, epinephrine may induce a type 1 Brugada pattern. Patients with Brugada pattern on ECG should be referred immediately to electrophysiology for consideration of implantation of a cardioverter-defibrillator device, given the association of Brugada pattern with sudden cardiac arrest and ventricular dysrhythmias.

Suspected hyponatremia-induced Brugada phenocopy

Brugada syndrome is a genetic condition that predisposes to an increased risk of ventricular fibrillation and sudden cardiac death in a structurally normal heart. The Brugada type 1 electrocardiogram (ECG) pattern may occur independently of the actual syndrome, and this clinical phenomenon is often referred to as Brugada phenocopy. There are several other factors which have been known to induce this electrocardiographic pattern, and currently, there is a paucity of literature with respect to the pattern that is observed in patients with electrolyte disturbances, specifically hyponatremia. This case report highlights a suspected hyponatremia-induced Brugada type 1 ECG pattern, which subsequently normalized following resolution of the electrolyte derangement.

Loperamide Mimicking Brugada Pattern

Brugada syndrome is an inherited arrhythmia that increases a patient's risk of sudden cardiac death. Certain pharmacologic agents may induce a transient Brugada pattern on surface electrocardiogram (EKG). One of these is loperamide, an over-the-counter agent commonly used to manage diarrhea. We report the case of a patient who experienced EKG changes that mimicked Brugada pattern after excessive intake of loperamide.

Long-term outcome of pulmonary vein isolation in patients with paroxysmal atrial fibrillation and Brugada syndrome

Aims

The therapeutical management of atrial fibrillation (AF) in the setting of Brugada syndrome (BS) might be challenging as many antiarrhythmic drugs (AADs) with sodium channel blocking properties might lead to to the development of ventricular arrhythmias. This study sought to evaluate the clinical outcome in a consecutive series of patients with BS having undergone pulmonary vein (PV) isolation by means of radiofrequency (RF) or cryoballoon (CB) ablation and the efficacy of catheter ablation for preventing inappropriate interventions delivered by implantable cardioverter defibrillators (ICD) on a 3-year follow up.

Methods and results

Twenty-three consecutive patients with BS (13 males; mean age was 47 ± 18 years) having undergone PV isolation for drug-resistant paroxysmal AF were enrolled. Eleven patients (48%) had an ICD implanted of whom four had inappropriate shocks secondary to rapid AF. Over a mean follow-up period of 35.0 ± 25.4 months (median 36 months) the freedom from AF recurrence after the index PV isolation procedure was 74% without AADs. Patients with inappropriate ICD interventions for AF did not present futher ICD shocks after AF ablation. No major complications occurred.

Conclusion

Catheter ablation is a valid therapeutic choice for patients with BS and paroxysmal AF considering the high success rates, the limitations of the AADs and the safety of the procedure, and it should be taken into consideration especially in those patients presenting inappropriate ICD shocks due to rapid AF.

Sex differences in cardiac electrophysiology

Women have a longer QT interval than men, which appears to evolve after puberty suggesting that sex hormones have an influence on cardiac electrophysiology. Sex hormones do in fact regulate cardiac ion channels via genomic and nongenomic pathways. Women are at greater risk for life-threatening arrhythmias under conditions that prolong the QT interval. In addition, women exhibit greater sensitivity to QT interval–prolonging drugs. Female sex has also an impact on propensity to cardiovascular disease, including atrial fibrillation. However, ex vivo recorded atrial action potentials (APs) from female and male patients in atrial fibrillation did not exhibit significant differences in shape, except that APs from women had slower upstroke velocity. It is concluded that sex-related differences should be taken into account not only in the clinics, but also in basic research.

Disease Modifiers of Inherited SCN5A Channelopathy

To date, a large number of mutations in SCN5A, the gene encoding the pore-forming α-subunit of the primary cardiac Na⁺ channel (Na_V1.5), have been found in patients presenting with a wide range of ECG abnormalities and cardiac syndromes. Although these mutations all affect the same Na_V1.5 channel, the associated cardiac syndromes each display distinct phenotypical and biophysical characteristics. Variable disease expressivity has also been reported, where one particular mutation in SCN5A may lead to either one particular symptom, a range of various clinical signs, or no symptoms at all, even within one single family. Additionally, disease severity may vary considerably between patients carrying the same mutation. The exact reasons are unknown, but evidence is increasing that various cardiac and non-cardiac conditions can influence the expressivity and severity of inherited SCN5A channelopathies. In this review, we provide a summary of identified disease entities caused by SCN5A mutations, and give an overview of co-morbidities and other (non)-genetic factors which may modify SCN5A channelopathies. A comprehensive knowledge of these modulatory factors is not only essential for a complete understanding of the diverse clinical phenotypes associated with SCN5A mutations, but also for successful development of effective risk stratification and (alternative) treatment paradigms.

Calcium in Brugada Syndrome: Questions for Future Research

The Brugada syndrome (BrS) is characterized by coved-type ST-segment elevation in the right precordial leads on the electrocardiogram (ECG) and increased risk of sudden cardiac death (SCD). While it is an inheritable disease, determining the true prevalence is a challenge, since patients may report no known family history of the syndrome, present with a normal spontaneous ECG pattern at the time of examination, and test negative for all known BrS-causative genes. In fact, SCD is often the first indication that a person is affected by the syndrome. Men are more likely to be symptomatic than women. Abnormal, low-voltage, fractionated electrograms have been found in the epicardium of the right ventricular outflow tract (RVOT). Ablation of this area abolishes the abnormal electrograms and helps to prevent arrhythmic recurrences. BrS patients are more likely to experience ventricular tachycardia/fibrillation (VT/VF) during fever or during an increase in vagal tone. Isoproterenol helps to reverse the ECG BrS phenotype. In this review, we discuss roles of calcium in various conditions that are relevant to BrS, such as changes in temperature, heart rate, and vagal tone, and the effects of gender and isoproterenol on calcium handling. Studies are warranted to further investigate these mechanisms in models of BrS.

Adolescent Seizure in the Emergency Department Due to Concomitant Brugada Syndrome

Brugada syndrome is an increasingly discussed entity in the emergency medicine and cardiology literature. However, there are few cases reported in the pediatric population. Seizure is a presentation common to pediatric emergency departments. This case report describes the clinical course, workup, and differential diagnosis of a 15-year-old male adolescent with first-time seizure and Brugada pattern on electrocardiogram. A brief review of the literature follows the case presentation.

Analysis of Safety Margin of Lithium Carbonate Against Cardiovascular Adverse Events Assessed in the Halothane-Anesthetized Dogs

Lithium is one of the classical drugs that have been widely used for treating bipolar disorder. However, several cardiac side effects including sick sinus syndrome, bundle branch block, ventricular tachycardia/fibrillation, non-specific T-wave abnormalities in addition to Brugada-type electrocardiographic changes have been noticed in patients who were given antidepressant, anticonvulsant, and/or antipsychotic drugs besides lithium. In this study, we assessed cardiohemodynamic and electrophysiological effects of lithium carbonate by itself to begin to analyze onset mechanisms of its cardiovascular side effects. Lithium carbonate in intravenous doses of 0.1, 1, and 10 mg/kg over 10 min was cumulatively administered with an interval of 20 min to the halothane-anesthetized beagle dogs (n = 4), which provided peak plasma Li⁺ concentrations of 0.02, 0.18, and 1.79 mEq/L, respectively, reflecting sub-therapeutic to toxic concentrations. The low and middle doses prolonged the ventricular effective refractory period at 30 min and for 5-30 min, respectively. The high dose decreased the heart rate for 45-60 min, delayed the intraventricular conduction for 15-20 min and the ventricular repolarization at 45 min, and prolonged the effective refractory period for 5-60 min. No significant change was detected in the other cardiovascular variables. Thus, lithium alone may have a wide safety margin against hemodynamic adverse events; however, it would directly and/or indirectly inhibit Na⁺ and K⁺ channels, which may synergistically increase the ventricular refractoriness from the sub-therapeutic concentration and decrease the heart rate at the supra-therapeutic one. These findings may partly explain its clinically observed various types of arrhythmias as well as electrocardiographic changes.

Brugada Phenocopy Induced by Recreational Drug Use

Recreational drugs are commonly abused in all age groups. Intoxication with these substances can induce silent but significant electrocardiographic signs which may lead to sudden death. In this case study, we present a 49-year-old male with no medical comorbidities who came to the emergency department requesting opioid detoxification. Toxicology screen was positive for cocaine, heroin, and cannabis. Initial electrocardiogram (EKG) showed features of a Brugada pattern in the right precordial leads, which resolved within one day into admission. This presentation is consistent with the recently recognized clinical entity known as Brugada phenocopy.

Lithium-induced electrocardiographic changes: A complete review

Lithium has been used for the treatment of bipolar disorder for more than 6 decades. Reports of cardiac side effects resulting in both benign electrocardiographic (ECG) changes and near fatal arrhythmias have been reported in the literature. A systematic literature search was conducted on 2 electronic databases-PubMed and Medline-for the time period between January 1970 and March 2016 using the key word "lithium," along with "electrocardiography" or "ECG." All articles and their references were then screened by title for relevance by 2 authors and a librarian. A total of 406 articles were found on literature search, of which 56 met the screening criteria. T wave inversion was the most frequently reported ECG finding. Other findings include sinus node dysfunction, sinoatrial blocks, PR prolongation, QT prolongation/dispersion, and ventricular tachyarrhythmias. Some cases have shown lithium-treated patients experiencing serious cardiac outcomes, such as ST elevation myocardial infarction, heart blocks, and the Brugada pattern. Electrical changes from lithium were found to be dependent on both duration of treatment and the serum lithium level. Although there are no standardized ECG guidelines, frequent monitoring of patients on lithium therapy can ensure the medication's safe use.

Diagnosis of Brugada's syndrome after subarachnoid injection of prilocaine

Brugada syndrome is an autosomal dominant genetic disease affecting sodium ion channels. It is characterised by right bundle branch block and ST elevation in the right precordial leads, and with no structural cardiac abnormalities. It is associated with sudden death. This disease may be unmasked by certain drugs and sudden changes in autonomic tone. Local anaesthetics may increase ECG changes due to a blockade of the sodium channels, mainly depending on the dose and the type of anaesthetic. Thus, there have been reported electrocardiographic changes consistent with Brugada syndrome, triggered after epidural or paravertebral infusion of bupivacaine and ropivacaine. The case is described of a 66 years old man, scheduled for inguinal herniorrhaphy as an outpatient. He had no history of syncope or arrhythmias. After spinal anaesthesia with 40mg of prilocaine the ECG showed ST elevation>2mm, and right bundle branch block in V1-V3.

Polytherapy with sodium channel-blocking antiepileptic drugs is associated with arrhythmogenic ST-T abnormality in patients with epilepsy

PURPOSE

Recent reports have documented the appearance of Brugada-type ST elevation in cases of overdose of antiepileptic drugs (AEDs). However, little is known about changes on electrocardiographs (ECGs) during AED use at therapeutic doses. AEDs may cause Brugada-type ST elevation or J-wave-like intraventricular conduction delays through an ion channel-blocking effect. In the present study, we sought to elucidate ECG abnormalities in patients on AED therapy.

METHODS

The study population consisted of 120 consecutive patients with epilepsy who continued to take AEDs and had ECGs recorded during these therapies. Their clinical background and ECGs were retrospectively analyzed. Brugada-type ST elevation was classified according to the consensus report on Brugada syndrome. A J-wave-like ECG abnormality was defined as the appearance of notching or slurring of the QRS complex (>0.1mV) in the inferior/lateral leads.

RESULTS

Of the 120 patients, 15 (12.5%) exhibited Brugada-type ST elevation and 35 (29.2%) showed a J-wave-like ECG abnormality. Polytherapy with sodium channel-blocking AEDs (e.g., carbamazepine, phenytoin, lamotrigine) was more frequently observed in patients with Brugada-type ST elevation (p=0.048). However, the serum concentrations of these medicines did not differ between patients with and without ECG abnormalities (carbamazepine: 7.9±4.1 vs. 7.2±5.9μg/dL; phenytoin: 12.7±4.1 vs. 15.5±9.5μg/dL, NS).

CONCLUSION

ST-T abnormalities were frequently seen in patients using AEDs. The presence of Brugada-type ST elevation was associated with polytherapy with sodium channel-blocking AEDs.

Brugada syndrome and its relevance in the perioperative period

Brugada syndrome is an autosomal dominant genetic disorder associated with an increased risk of sudden cardiac death, as well as ventricular tachyarrhythmias. The defective cardiac sodium channels result in usual electrocardiographic findings of a coved-type ST elevation in precordial leads V1 to V3. The majority of patients have uncomplicated courses with anesthesia, surgery, and invasive procedures. However there is risk of worsening ST elevation and ventricular arrhythmias due to perioperative medications, surgical insult, electrolyte abnormalities, fever, autonomic nervous system tone, as well as other perturbations. Given the increasing numbers of patients with inherited conduction disorders presenting for non-cardiac surgery that are at risk of sudden cardiac death, safe anesthetic management depends upon a detailed knowledge of these conditions.

Sugammadex in a Patient with Brugada Syndrome

Brugada Syndrome was first described in 1992 by Pedro Brugada as a genetic syndrome that is characterized by ventricular arrhythmias that may result in sudden cardiac arrest. In particular, a right bundle branch block and ST segment elevation in the right precordial leads are observed. Many perioperative pharmalogical and physiological factors can trigger malignant arrhythmias. Although it is a rare condition, the anaesthestic management of Brugada syndrome is important because of the potentially fatal complications. Many anaesthetics have been administered during the operation of patients with Brugada Syndrome. The use of sugammadex instead of the anaesthetic management of patients with Brugada syndrome is discussed in this study.

Atrial arrhythmias in inherited arrhythmogenic disorders

Atrial arrhythmias are being increasingly recognized in inherited arrhythmogenic disorders particularly in patients with Brugada syndrome and short QT syndrome. Atrial arrhythmias in inherited arrhythmogenic disorders have significant epidemiologic, clinical, and prognostic implications. There has been progress in the understanding of underlying genetic characteristics and the mechanistic link between atrial arrhythmias and inherited arrhythmogenic disorders. Appropriate management of these patients is of paramount importance.

Electrocardiac effects associated with lithium toxicity in children: an illustrative case and review of the pathophysiology

Lithium is a potent psychotherapeutic agent that has gained wide acceptance in paediatrics, especially as adjunct treatment for severe behavioural, anxiety, and attention-deficit hyperactivity disorders, along with bipolar conditions. Its cardiac toxicity has been well-documented in adults; however, information is limited regarding lithium's effects on the heart in children. Therefore, paediatric cardiologists following-up children on lithium therapy should be cognizant of the cardiac side-effects and pathophysiology associated with this drug. In this manuscript, we used an illustrative case of a child who presented with lithium poisoning, in order to highlight adverse clinical manifestations that can arise from this medication. The cardiac cell membrane is thought to be the primary site of lithium's action. Thus, we reviewed lithium's effects on membrane electrogenic pumps and channels involved in the distribution and passage of sodium, potassium, and calcium across the sarcolemma, as these ions, and their associated currents, are the primary determinates of the action potentials underlying auto-rhythmicity and contractile activity of the heart.

Inferior ST-Elevation Acute Myocardial Infarction or an Inferior-Lead Brugada-like Electrocardiogram Pattern Associated With the Use of Pregabalin and Quetiapine?

The Brugada electrocardiogram pattern is characterized by coved-type ST-elevation (>2 mm) in the right precordial leads. We report the case of a 62-year-old man, with bipolar disorder, admitted to the emergency department because of dyspnea and chest discomfort. The patient was on treatment with pregabalin and quetiapine. Unexpectedly, electrocardiogram at admission showed diffuse ST-elevation, more evident in inferior leads, where a Brugada-like pattern was present. The patient underwent coronary angiography with a diagnosis of suspected acute coronary syndrome. Coronary angiography, however, showed mild coronary artery disease not requiring coronary angioplasty. Echocardiography did not reveal left ventricular dysfunction or pericardial effusion. Troponin levels remained normal over serial controls. Eventually, chest radiography showed lung opacities and consolidation suggestive for pneumonia. To the best of our knowledge, this is one of the first cases showing a transient Brugada-like electrocardiogram pattern in inferior leads, probably amplified by the administration of pregabalin and quetiapine.

Brugada ECG patterns in athletes

Brugada syndrome is responsible for up to 4% of all sudden cardiac deaths worldwide and up to 20% of sudden cardiac deaths in patients with structurally normal hearts. Heterogeneity of repolarization and depolarization, particularly over the right ventricle and the outflow tract, is responsible for the arrhythmogenic substrate. The coved Type I ECG pattern is considered diagnostic of the syndrome but its prevalence is very low. Distinguishing between a saddle back Type 2 Brugada pattern and one of many "Brugada-like" patterns presents challenges especially in athletes. A number of criteria have been proposed to assess Brugada ECG patterns. Proper precordial ECG lead placement is paramount. This paper reviews Brugada syndrome, Brugada ECG patterns, and recently proposed criteria. Recommendations for evaluating a Brugada ECG pattern are provided.

Brugada syndrome ECG is highly prevalent in schizophrenia

BACKGROUND

The causes of increased risk of sudden cardiac death in schizophrenia are not resolved. We aimed to establish (1) whether ECG markers of sudden cardiac death risk, in particular Brugada-ECG pattern, are more prevalent among patients with schizophrenia, and (2) whether increased prevalence of these ECG markers in schizophrenia is explained by confounding factors, notably sodium channel-blocking medication.

METHODS AND RESULTS

In a cross-sectional study, we analyzed ECGs of a cohort of 275 patients with schizophrenia, along with medication use. We determined whether Brugada-ECG was present and assessed standard ECG measures (heart rate, PQ-, QRS-, and QT-intervals). We compared the findings with nonschizophrenic individuals of comparable age (the Netherlands Study of Depression and Anxiety [NESDA] cohort; N=179) and, to account for assumed increased aging rate in schizophrenia, with individuals 20 years older (Hoorn cohort; n=1168), using multivariate regression models. Brugada-ECG was significantly more prevalent in the schizophrenia cohort (11.6%) compared with NESDA controls (1.1%) or Hoorn controls (2.4%). Moreover, patients with schizophrenia had longer QT-intervals (410.9 versus 393.1 and 401.9 ms; both P<0.05), increased proportion of mild or severe QTc prolongation (13.1% and 5.8% versus 3.4% and 0.0% [NESDA], versus 5.1 and 2.8% [Hoorn]), and higher heart rates (80.8 versus 61.7 and 68.0 beats per minute; both P<0.05). The prevalence of Brugada-ECG was still increased (9.6%) when patients with schizophrenia without sodium channel-blocking medication were compared with either of the control cohorts.

CONCLUSIONS

Brugada-ECG has increased prevalence among patients with schizophrenia. This association is not explained by the use of sodium channel-blocking medication.

The Brugada syndrome revisited

The Brugada syndrome is a rare but well-defined cause of sudden cardiac death. The key underlying abnormality is a decrease in net depolarising current due to a genetic defect, though recent evidence also implicates structural abnormalities in some patients. Diagnosis requires a Brugada-type ECG as well as typical clinical features: such clinical considerations are currently key in guiding risk stratification and hence management. Whilst pharmacological therapies are under investigation, the only intervention with a robust evidence base remains insertion of an implantable cardioverter defibrillator. Further research will be required to allow more effective risk stratification and hence more rational therapy.