[Recurrent ventricular fibrillation during a febrile illness in a patient with the Brugada syndrome]

Arrhythmic events in Brugada syndrome patients induced by fever

INTRODUCTION

The Brugada syndrome is associated with arrhythmic events, which may even lead to sudden cardiac death (SCD) as it causes arrhythmic events. A typical Brugada syndrome ECG type I can be triggered at fever situations. The aim of this pooled meta-analysis is to further explore the baseline characteristics and the association of fever to BrS-related arrhythmic events.

METHODS

We compiled data from a search of databases (PubMed, Web of Science, Cochrane Library, and Google Scholar). We included 17 studies including 14 case reports and a total of 53 patients.

RESULTS

Our population including 53 patients showed a male predominance of 92% with a mean age of 40.6 ± 17.7 years. 58% of patients had a family history of SCD or BrS. Genetic screening was performed in 14 patients (26%) and revealed a SCN5A mutation in 21% of the patients. ICD implantation was initiated in six patients. 75% (n = 39) of patients did not have symptoms before the fever event. Symptoms at fever included life-threatening arrhythmia such as ventricular fibrillation (VF) or ventricular tachycardia (VT; 17%), syncope (13%), and cardiac arrest or aborted SCD (13%). One patient developed electrical storm which led to not aborted SCD.

CONCLUSION

Fever is a great risk factor for arrhythmia events in BrS patients. Patients with known fever triggered Brugada syndrome should be surveilled closely during fever and be started on antipyretic therapy as soon as possible.

Brugada Pattern in Diabetic Ketoacidosis: A Case Report and Scoping Study

Brugada syndrome is a rare cardiac arrhythmia which is associated with right bundle branch block pattern (RBBB) and ST-segment elevation in right precordial leads. SCNA5 mutation is the most common genetic abnormality associated with Brugada syndrome. Brugada pattern not related to genetic mutations has been previously reported in the setting of fever, metabolic conditions, lithium use, marijuana and cocaine abuse, ischemia and pulmonary embolism, myocardial and pericardial diseases. Multiple isolated cases of Brugada pattern associated with diabetic ketoacidosis (DKA) have been previously reported. We here present a case of type 1 Brugada pattern in a 23 year-old-male who presented with DKA. Brugada pattern in DKA is attributed to acidosis and multiple electrolyte abnormalities including hyperkalemia which alter ion channel expression in the heart thus leading to Brugada pattern which subsequently resolved with treatment of DKA. In such patients, Brugada pattern is not reproducible on procainamide induction cardiac electrophysiology study (EPS). Our scoping study demonstrates male predominance 20/22 cases of (DELETE this highlighted area) Brugada pattern in DKA, a finding that is consistent with prevalence of this disease among males.

Brugada Syndrome: Clinical, Genetic, Molecular, Cellular, and Ionic Aspects

Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome first described as a new clinical entity in 1992. Electrocardiographically characterized by distinct coved type ST segment elevation in the right-precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young adults, and less frequently in infants and children. The electrocardiographic manifestations of BrS are often concealed and may be unmasked or aggravated by sodium channel blockers, a febrile state, vagotonic agents, as well as by tricyclic and tetracyclic antidepressants. An implantable cardioverter defibrillator is the most widely accepted approach to therapy. Pharmacologic therapy is designed to produce an inward shift in the balance of currents active during the early phases of the right ventricular action potential (AP) and can be used to abort electrical storms or as an adjunct or alternative to device therapy when use of an implantable cardioverter defibrillator is not possible. Isoproterenol, cilostazol, and milrinone boost calcium channel current and drugs like quinidine, bepridil, and the Chinese herb extract Wenxin Keli inhibit the transient outward current, acting to diminish the AP notch and thus to suppress the substrate and trigger for ventricular tachycardia or fibrillation. Radiofrequency ablation of the right ventricular outflow tract epicardium of patients with BrS has recently been shown to reduce arrhythmia vulnerability and the electrocardiographic manifestation of the disease, presumably by destroying the cells with more prominent AP notch. This review provides an overview of the clinical, genetic, molecular, and cellular aspects of BrS as well as the approach to therapy.

A hot topic: temperature sensitive sodium channelopathies

Perturbations to body temperature affect almost all cellular processes and, within certain limits, results in minimal effects on overall physiology. Genetic mutations to ion channels, or channelopathies, can shift the fine homeostatic balance resulting in a decreased threshold to temperature induced disturbances. This review summarizes the functional consequences of currently identified voltage-gated sodium (NaV) channelopathies that lead to disorders with a temperature sensitive phenotype. A comprehensive knowledge of the relationships between genotype and environment is not only important for understanding the etiology of disease, but also for developing safe and effective treatment paradigms.

Brugada Syndrome 2010

The Brugada syndrome is a genetically determined cardiac disorder, presenting with characteristic electrocardiogram features and high risk of sudden cardiac death from polymorphic ventricular tachycardia/ventricular fibrillation in young individuals with a structurally normal heart. Scientific knowledge about the disease has grown exponentially in recent years. Two consensus reports on the disease were published (in 2002 and 2005) in an effort to state diagnostic criteria, risk stratification, and treatment indications. However, substantial controversies remain, especially considering risk stratification of asymptomatic patients. Given the enormous amount of valuable information collected by many groups since the consensus reports, current diagnostic criteria, recommended prognostic tools, and treatment must be reviewed. This article briefly reviews recent advances in understanding of Brugada syndrome and its genetic and molecular basis, arrhythmogenic mechanisms, and clinical course. An update of tools for risk stratification and treatment of the condition is also included.

Brugada syndrome associated with supraventricular tachycardia: diagnostic and therapeutic strategies

We report the case of a patient with Brugada syndrome and a history of palpitations who presented with an episode of syncope and developed supraventricular tachycardia in the electrophysiological study. The patient was treated with radiofrequency ablation for the supraventricular tachycardia and an implantable cardioverter defibrillator for the Brugada syndrome. At 18 months following implantation of the defibrillator an electrical storm with ventricular fibrillation episodes occurred followed by appropriate discharges of the defibrillator.

Brugada syndrome

First described in 1992, Brugada syndrome is characterized by a specific electrocardiographic pattern in the right precordial leads and susceptibility to ventricular arrhythmias and sudden death. Brugada syndrome is included among the channelopathies, primary electrical disorders that, characteristically, are not associated with concomitant structural cardiac abnormalities. In recent years, substantial preclinical and clinical research has led to the identification of multiple causative mutations and to understanding of the mechanisms underlying the development of the characteristic phenotype and of the factors that determine clinical prognosis in patients. Nevertheless, there remain numerous unresolved questions which provide an impetus for ongoing active research into the condition. This article provides a summary of what is currently known about Brugada syndrome and an overview of the principal preclinical and clinical studies that have made the most significant contributions to our understanding of the condition.

Brugada syndrome

First described in 1992, Brugada syndrome is characterized by a specific electrocardiographic pattern in the right precordial leads and susceptibility to ventricular arrhythmias and sudden death. Brugada syndrome is included among the channelopathies, primary electrical disorders that, characteristically, are not associated with concomitant structural cardiac abnormalities. In recent years, substantial preclinical and clinical research has led to the identification of multiple causative mutations and to understanding of the mechanisms underlying the development of the characteristic phenotype and of the factors that determine clinical prognosis in patients. Nevertheless, there remain numerous unresolved questions which provide an impetus for ongoing active research into the condition. This article provides a summary of what is currently known about Brugada syndrome and an overview of the principal preclinical and clinical studies that have made the most significant contributions to our understanding of the condition.

Brugada syndrome

First introduced as a new clinical entity in 1992, the Brugada syndrome is associated with a relatively high risk of sudden death in young adults, and occasionally in children and infants. Recent years have witnessed a striking proliferation of papers dealing with the clinical and basic aspects of the disease. Characterized by a coved-type ST-segment elevation in the right precordial leads of the electrocardiogram (ECG), the Brugada syndrome has a genetic basis that thus far has been linked only to mutations in SCN5A, the gene that encodes the alpha-subunit of the sodium channel. The Brugada ECG is often concealed, but can be unmasked or modulated by a number of drugs and pathophysiological states including sodium channel blockers, a febrile state, vagotonic agents, tricyclic antidepressants, as well as cocaine and propranolol intoxication. Average age at the time of initial diagnosis or sudden death is 40 +/- 22, with the youngest patient diagnosed at 2 days of age and the oldest at 84 years. This review provides an overview of the clinical, genetic, molecular, and cellular aspects of the Brugada syndrome, incorporating the results of two recent consensus conferences. Controversies with regard to risk stratification and newly proposed pharmacologic strategies are discussed.

Therapy for the Brugada syndrome

The Brugada syndrome is a congenital syndrome of sudden cardiac death first described as a new clinical entity in 1992. Electrocardiographically characterized by a distinct coved-type ST segment elevation in the right precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young and otherwise healthy adults, and less frequently in infants and children. The ECG manifestations of the Brugada syndrome are often dynamic or concealed and may be revealed or modulated by sodium channel blockers. The syndrome may also be unmasked or precipitated by a febrile state, vagotonic agents, alpha-adrenergic agonists, beta-adrenergic blockers, tricyclic or tetracyclic antidepressants, a combination of glucose and insulin, and hypokalemia, as well as by alcohol and cocaine toxicity. An implantable cardioverter-defibrillator (ICD) is the most widely accepted approach to therapy. Pharmacological therapy aimed at rebalancing the currents active during phase 1 of the right ventricular action potential is used to abort electrical storms, as an adjunct to device therapy, and as an alternative to device therapy when use of an ICD is not possible. Isoproterenol and cilostazol boost calcium channel current, and drugs like quinidine inhibit the transient outward current, acting to diminish the action potential notch and thus suppress the substrate and trigger for ventricular tachycardia/fibrillation (VT/VF).

Brugada syndrome

The Brugada syndrome is an autosomal dominant disease with incomplete penetrance that may cause syncope and sudden cardiac death in young individuals with a normal heart. It is characterized by an electrocardiographic pattern of complete or incomplete right bundle branch block and ST segment elevation in leads V1-V3. One of the genes linked to this syndrome is SCN5A, the gene encoding for the cardiac sodium channel. Mutations in SCN5A cause a functional reduction in the availability of cardiac sodium current in Brugada syndrome. However, only 20-25% of patients affected by this syndrome have mutations on this gene. A novel gene locus on chromosome 3, distinct from SCN5A, has been identified recently. The relative male preponderance of the phenotype, despite equal inheritance of the gene in males and females, has led to the speculation of a role for testosterone in the phenotype. The disease could manifest at first time as cardiac arrest without any previous symptom, and the electrocardiographic pattern could be intermittent, requiring a pharmacological challenge with Class I antiarrhythmic drugs to unmask ST elevation. Several conditions producing Brugada-like electrocardiographic patterns should be borne in mind and excluded while making a diagnosis of the Brugada syndrome. The management is difficult as pharmacological agents are not universally effective. The mode of treatment recommended by the majority of cardiac electrophysiologists is the implantation of a cardioverter defibrillator. Symptomatic patients with inducible ventricular arrhythmias and a positive family history should be considered for prophylactic implantation of a cardioverter defibrillator.

Brugada syndrome: report of the second consensus conference: endorsed by the Heart Rhythm Society and the European Heart Rhythm Association

Since its introduction as a clinical entity in 1992, the Brugada syndrome has progressed from being a rare disease to one that is second only to automobile accidents as a cause of death among young adults in some countries. Electrocardiographically characterized by a distinct ST-segment elevation in the right precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young and otherwise healthy adults, and less frequently in infants and children. Patients with a spontaneously appearing Brugada ECG have a high risk for sudden arrhythmic death secondary to ventricular tachycardia/fibrillation. The ECG manifestations of Brugada syndrome are often dynamic or concealed and may be unmasked or modulated by sodium channel blockers, a febrile state, vagotonic agents, alpha-adrenergic agonists, beta-adrenergic blockers, tricyclic or tetracyclic antidepressants, a combination of glucose and insulin, hypo- and hyperkalemia, hypercalcemia, and alcohol and cocaine toxicity. In recent years, an exponential rise in the number of reported cases and a striking proliferation of articles defining the clinical, genetic, cellular, ionic, and molecular aspects of the disease have occurred. The report of the first consensus conference, published in 2002, focused on diagnostic criteria. The present report, which emanated from the second consensus conference held in September 2003, elaborates further on the diagnostic criteria and examines risk stratification schemes and device and pharmacological approaches to therapy on the basis of the available clinical and basic science data.

Brugada syndrome: from cell to bedside

Since its introduction as a new clinical entity in 1992, the Brugada syndrome has attracted great interest because of its high incidence in many parts of the world and its association with high risk for sudden death in infants, children, and young adults. Recent years have witnessed an exponential rise in the number of reported cases and a striking proliferation of articles serving to define the clinical, genetic, cellular, ionic, and molecular aspects of the disease. A consensus report published in 2002 delineated diagnostic criteria for the syndrome. A second consensus conference was held in September 2003. This review provides an in-depth overview of the clinical, genetic, molecular, and cellular aspects of the Brugada syndrome, incorporating the results of the two consensus conferences, and the numerous clinical and basic publications on the subject. The proposed terminology, diagnostic criteria, risk stratification schemes, and device and pharmacologic approach to therapy discussed are based on available clinical and basic studies and should be considered a work-in-progress that will without doubt require fine-tuning as confirmatory data from molecular studies and prospective trials become available.

Brugada-like electrocardiographic changes during influenza infection

We describe a 32-year-old man with electrocardiographic (ECG) changes consistent with Brugada syndrome and influenza virus infection. The ECG pattern changed after 1 week to one of early repolarization in V1 and V2. This case suggests an association between Brugada syndrome and viral infection.

Fibrilación ventricular recurrente en un paciente con síndrome de Brugada: tratamiento eficaz con procainamida

Brugada syndrome is a clinical and electrocardiographic entity characterized by ST segment elevation in the right precordial ECG leads and sudden death or syncope secondary to malignant ventricular arrhythmia, and has a high recurrence rate. We report a patient with this syndrome who had received an automatic implantable defibrillator, who presented with multiple appropriate discharges because of recurrent episodes of ventricular fibrillation. All episodes were started by a premature ventricular beat of the same morphology and coupling interval. Endovenous procainamide administration, paradoxically, was effective in preventing new episodes. The beneficial antiarrhythmic effect of procainamide in this patient is discussed.

[Usefulness of the implantable subcutaneous recorder in the diagnosis of recurrent syncope of unknown etiology in patients without structural heart disease and negative tilt test and electrophysiological study]

BACKGROUND AND OBJECTIVES

In up to 38% of the cases, the etiology of syncope difficult to determine. The main obstacle for diagnosis of the causes of syncope lies in the unpredictable frequency of episodes. Development of implantable loop recorders allows long term electrocardiographic monitoring. The aim of this study was to evaluate the usefulness of the implantable loop recorder for the diagnosis of recurrent syncope of unknown origin.

PATIENTS AND METHODS

From May 1991 to April 1999, a cohort of 176 patients with recurrent syncope was prospectively assessed. Investigations, including Holter monitoring, Tilt Test and electrophysiological study, allowed the determination of the etiology in 161 patients. The remaining 15 patients, without structural cardiac disease were selected for continuous electrocardiographic monitoring using an implantable loop recorder.

RESULTS

During follow up after implant, 15 +/- 2 months (X- +/- SEM), 9 patients showed recurrence of symptoms concordant with prior episodes (time: 105 +/- 30 days). In 7 cases records during symptoms were diagnostic (0.47; CI 95%: 0.21-0.73), in 3 cases a diagnosis with documented arrhythmia was achieved, and in 4 other cases a presumptive clinical diagnosis of non-arrhythmic cause was made. In 8 patients, 6 with no recurrences, diagnosis was not possible. There were no complications related to the use of the device.

CONCLUSIONS

The strategy of long term monitoring with the implantable loop recorder is safe and effective in patients with recurrent syncope of unknown etiology.

The Brugada syndrome

The Brugada syndrome is a hereditary disease causing sudden cardiac death in apparently healthy individuals with a structurally normal heart. The disease is caused by mutations in the cardiac sodium channel gene SCN5A. Patients with this disease have a peculiar electrocardiogram with elevation of the ST segment in leads V1 to V3, an electrocardiogram that every doctor should recognize. There exist variants of the electrocardiogram with minimal ST segment elevation and even concealed forms that can only be unmasked by the administration of class I antiarrhythmic drugs. When left untreated or when treated with all known antiarrhythmic drugs, patients with Brugada syndrome have a high mortality (approximately 10% per year). The only effective treatment to prevent sudden death is the implantable defibrillator.