Brugada Syndrome: An Electrical Storm without Warning

Brugada Syndrome (BrS) is an inherited channelopathy causing sodium channel dysfunction in cardiac myocyte. These patients are prone to develop Ventricular Fibrillation (VF) or polymorphic Ventricular Tachycardia (VT). Next to coronary artery disease and cardiomyopathies, BrS is an important cause of sudden cardiac death. We report here a case of 22 year unmarried female with "unexplained" cardiac arrest without prior history of syncope and family history of sudden cardiac death. She was resuscitated out of hospital in some local dispensary in rural settings and after prolonged hypoxia with its neurological sequelae, she eventually died. BrS should be considered in differentials of unexplained cardiac arrest even in patients without family history of sudden cardiac death. First episode of VT/VF in BrS patients can be life threatening. Only prompt cardioversion / defibrillation can save life. We have suggested some measures to identify patients of BrS.

[Role of standard resting ECG in the assessment of sudden cardiac death risk]

Today the ECG is still, over 100 years after its invention (Willem Einthoven 1903), the most commonly used diagnostic procedure in clinical cardiology. In recent years, we have accumulated knowledge that has significantly expanded the diagnostic possibilities of ECG, through the recognition of patterns associated with a number of primary electrical diseases of the myocardium, the so-called inherited arrhythmogenic diseases. These clinical entities are caused by gene mutations that determine a substrate leading to the onset of life-threatening rhythm disturbances. The study of ECG abnormalities in these diseases showed characteristic phenotypic traits, which in combination with information derived from molecular genetics, have allowed using the ECG as a prognostic tool as well as a diagnostic test. The assessment of genotype-phenotype correlations in inherited arrhythmogenic diseases has allowed to advance the idea of the ECG as an inheritable trait. Such heritable quantitative traits are potentially related to the risk of sudden death in the general population, which is known to have a familial predisposition. This article summarizes the pathophysiology and phenotypic manifestation of the main arrhythmogenic diseases. Also shown are current possibilities and limitations of the use of a simple and low-cost technology, not only as a tool for diagnosis but also as a tool to identify prognostic markers. We will show how, rather surprisingly, the ECG often allows extracting the most important information for appropriate risk classification and clinical management.

Brugada syndrome combined with monomorphic ventricular tachycardia and atrioventricular nodal reentrant tachycardia

A 41-year-old man developed sustained monomorphic ventricular tachycardia (VT) with a left bundle branch block and inferior axis pattern during treadmill exercise concomitantly with unmasking of the typical Brugada electrocardiography (ECG) pattern. The typical ECG phenotype was provoked by a class IC drug. VT was not inducible with programmed electrical stimulation, but premature ventricular beat and non-sustained VT with the same morphology increased in frequency with isoproterenol treatment. Additionally, atrioventricular nodal reentrant tachycardia (AVNRT) was induced by electrical stimulation and VT and AVNRT were treated by radiofrequency catheter ablation.

PYREXIA-INDUCED BRUGADA PHENOCOPY

Brugada syndrome (BS) is characterized by a typical electrocardiographic (ECG) pattern in the right precordial leads and a predisposition to develop ventricular arrhythmias. Mutations in a subunit of cardiac sodium channel (SCN5A) have been linked to BS. Experimental studies in the literature suggest that this dysfunction of the mutated channel can be temperature sensitive. Several antiarrhythmics have been used in the management of BS but Implantable Cardioverter Defibrillators (ICD) remains the only effective treatment. We herewith present the case report of a 62-year-old man who developed a type-2 Brugada ECG phenotype in a febrile state with complete resolution once the fever subsided.

[ETACISIN-INDUCED BRUGADA SYNDROME IN A PATIENT WITH LONG-STANDING SUPRAVENTRICULAR EXTRASYSTOLE]

Brugada syndrome is a commonest cause of malignant disorders of cardiac rhythm associated with sudden death. It is diagnosed based on characteristic ECG signs and ventricular arrhythmia. This paper reports a 49 year-old patient with long-standing latent BS manifest as supraventricular and transient blockade of the right branch of the His bundle. The ECG pattern of BS became apparent in association with a 7 day treatment with class IC antiarrhythmic agent etacisin. Diagnostic difficulties account for the fact that the disease was initially described as myocardial infarction. Diagnosis of BS was confirmed by an electrophysiological study in which stable ventricular tachycardia and fibrillation were induced by etacisin. A cardioverter defibrillator was implanted to the patient.

[Brugada Syndrome: Possibilities of the Use of Noninvasive Electrocardiographic Mapping. A Case Report]

Patient P., 50 years old, male, with type I Brugada syndrome was examined. The patient had aborted sudden death event (2006) in his clinical history, ICD Gem III VR was implanted in 2006, ICDLumax DR was reimplanted in 2012. The patient had coved type pattern in right precordial ECG-leads. The p.E553X mutation in SCN5A gene, whish encodes the sodium channel α-subunit, was found. Noninvasive electrocardiographic mapping was performed. Significant changes of local unipolar electrograms including QRS fragmentation, ST segment elevation and late ventricular potentials were identified in the epicardium of the right ventricle outflow tract. Thus, the presented case demonstrates that noninvasive electrocardiographic mapping methodology allows to determine and visualize arrhythmogenic substrate in patients with inherited channelopathies.

Prevalence of type 1 brugada electrocardiographic pattern evaluated by twelve-lead twenty-four-hour holter monitoring

Patients with drug-induced type 1 Brugada electrocardiograms (BrECGs) are considered to have good prognosis. Spontaneous type 1 is, instead, considered a risk factor; however, it is probably underestimated because of the BrECG fluctuations. The aim of this study was to analyze, in a large population of patients with Br, the real prevalence of type 1 BrECG using 12-lead 24-hour Holter monitoring (12L-Holter) and its correlation with the time of the day. We recorded 303 12L-Holter in 251 patients. Seventy-five (30%) patients exhibited spontaneous type 1 BrECG at 12-lead ECG (group 1) and 176 (70%) had only drug-induced type 1 (group 2). Type 1 BrECG was defined as "persistent" (>85% of the recording), "intermittent" (<85%), or "absent." In group 1, 12% showed persistent type 1 at 12L-Holter, 57% intermittent type 1%, and 31% never had type 1; in group 2, none had persistent type 1, 20% had intermittent type 1%, and 80% never showed type 1. To evaluate the circadian fluctuations of BrECG, 4 periods in the day were considered. Type 1 BrECG was more frequent between 12-noon and 6 p.m. (52%, p <0.001). In conclusion, in patients with drug-induced type 1, spontaneous type 1 BrECG can be detected more frequently with 12L-Holter than with conventional follow-up with periodic ECGs and this has important implications in the risk stratification. 12L-Holter recording might avoid 20% of the pharmacological challenges with sodium channel blockers, which are not without risks, and should thus be considered as the first screening test, particularly in children or in presence of borderline diagnostic basal ECG.

Syncope in a febrile state: A case report of Brugada syndrome

In 1992, Brugada and Brugada first described a new entity, which became known as Brugada syndrome, that is associated with a high risk of ventricular arrhythmias and sudden cardiac death in patients without structural heart disease. This syndrome is characterized by a distinct electrocardiographic phenotype, type 1 Brugada pattern, consisting of a coved ST-segment elevation (≥0.2 mV) followed by a negative T wave in more than one right precordial lead. This pattern is dynamic, and can be spontaneous or concealed, but is unmasked under certain circumstances, like febrile states. The authors report a case in which the diagnosis of Brugada syndrome was made in the course of etiologic investigation of recurrent syncope in a febrile state.

Transcranial magnetic stimulation as an antidepressant alternative in a patient with Brugada syndrome and recurrent syncope

Brugada syndrome (BrS) is a common occult cause of sudden cardiac arrest in otherwise healthy-appearing adults. The pathognomonic electrocardiographic pattern may be unmasked only by certain medications, many of which are unknown. We report a case of a depressed but otherwise healthy man with an asymptomatic right bundle branch block on electrocardiography who experienced antidepressant-induced BrS and ultimately recovered with transcranial magnetic stimulation (TMS). After an initial trial of nortriptyline, the patient's depressive symptoms improved; however, he experienced a syncopal event and was subsequently diagnosed as having BrS. Cross titration to bupropion, which had not previously been known to exacerbate BrS, was followed by another cardiac event. As a result, the patient was referred for TMS as a substitute for pharmacotherapy. After 31 TMS sessions over 8 weeks, the patient demonstrated significant improvement by subjective report and objective reduction in his Patient Health Questionnaire-9 scores from 10 (moderate) to 1 (minimal). Transcranial magnetic stimulation is a Food and Drug Administration-approved nonpharmacologic treatment for depression. Given the potential lethality of BrS with known and unknown psychopharmacologic agents, providers should consider TMS as first-line therapy in this patient population. Bupropion should be added to the list of agents known to exacerbate this disease.

Syncope in Brugada syndrome: prevalence, clinical significance, and clues from history taking to distinguish arrhythmic from nonarrhythmic causes

BACKGROUND

Syncope in Brugada syndrome (BrS) patients is a sign of increased risk for sudden cardiac death and usually is ascribed to cardiac arrhythmias. However, syncope often occurs in the general population, mostly from nonarrhythmic causes (eg, reflex syncope).

OBJECTIVE

The purpose of this study was to distinguish arrhythmic events from nonarrhythmic syncope in BrS and to establish the clinical relevance of nonarrhythmic syncope.

METHODS

We reviewed the patient records of 342 consecutively included BrS patients and conducted systematic interviews in 141 patients with aborted cardiac arrest (ACA) or syncope.

RESULTS

In total, 23 patients (7%) experienced ECG-documented ACA and 118 (34%) syncope; of these 118, 67 (57%) were diagnosed with suspected nonarrhythmic syncope. Compared to suspected nonarrhythmic syncope patients, ACA patients were older at first event (45 vs 20 years), were more likely to be male (relative risk 2.1) and to have urinary incontinence (relative risk 4.6), and were less likely to report prodromes. ACA was never triggered by hot/crowded surroundings, pain or other emotional stress, seeing blood, or prolonged standing. During follow-up (median 54 months), ACA rate was 8.7% per year among ACA patients and 0% per year among suspected nonarrhythmic syncope patients.

CONCLUSION

Syncope, especially nonarrhythmic syncope, often occurs in BrS. The high incidence of nonarrhythmic syncope must be taken into account during risk stratification. Arrhythmic events and nonarrhythmic syncope may be distinguished by clinical characteristics (absence of prodromes and, particularly, specific triggers), demonstrating the importance of systematic history taking.

Ventricular fibrillation induction and diffuse abnormal ST-segment response to ajmaline in a patient with apparent pre-existing dynamic right bundle branch block

OBJECTIVE

ST-segment elevation in the right precordial electrocardiography (ECG) leads in Brugada syndrome (BS) can be unmasked by class I anti-arrhythmic drugs (sodium channel blockers) administration. It is still debated whether this ECG pattern is better explained by abnormal repolarization or ventricular conduction and depolarization. Conduction diseases can conceal type 1 BS-like ECG in standard V1-V3 leads. ECG alterations were found also in alternative leads. The role of electrophysiology study (EPS) in sudden cardiac death risk stratification remains controversial, and could depend on the phenotypic expression of the cardiac sodium channels disease.

CASE REPORT

We describe unmasked diffuse J-point and ST-segment anomalies in peripheral and precordial ECG leads and ventricular fibrillation (VF) induction by EPS after ajmaline administration in a patient with pre-existing atypical right bundle branch block (RBBB) concealing subtle anomalies in standard V1-V3 leads. RBBB was influenced by the underlying BS-like ECG associating repolarization anomaly and pre-existing conduction disease. EPS induced VF when RBBB was associated with BS-like ECG, and failed to induce VF when RBBB was present alone.

CONCLUSIONS

BS phenotype heterogeneity requires further studies to improve the knowledge of its pathophysiological mechanisms associated with conduction diseases in order to better identify an individual therapy and prognostic stratification.

Diagnosis of Brugada syndrome during fever: a case report from a tertiary care centre

A 19 yr old boy came to our hospital with high grade fever since two days. We made clinical impression of malaria. Routine ECG showed rsr pattern and ST elevation in V1,V2. After excluding all other conditions and retrospective counselling, we made diagnosis of Brugada syndrome. Screening baseline ECG of his family members is positive for Brugada ECG pattern. Echocardiogram is normal. Since patient is asymptomatic, we referred him to higher cardiac centre for electrophysiological testing.

Early repolarisation and J wave syndromes

J wave syndrome has emerged as a significant cause of Idiopathic ventricular fibrillation (IVF) responsible for sudden cardiac death. A large body of data is now available on genesis, genetics and ionic mechanisms of J wave syndromes. Two of these viz., Early repolarization syndrome (ER) and Brugada syndrome (BrS) are fairly well characterized enabling correct diagnosis in most patients. The first part of repolarization of ventricular myocardium is governed by Ito current i.e., rapid outward potassium current. The proposed mechanism of ventricular fibrillation (VF) and ventricular tachycardia (VT) storms is the faster Ito current in the epicardium than in the endocardium results in electrical gradient that forms the substrate for phase 2 reentry. Prevention of Ito current with quinidine supports this mechanism. Majority of ER patterns in young patients are benign. The key issue is to identify those at increased risk of sudden cardiac death. Association of both ER syndrome and Brugada syndrome with other disease states like coronary artery disease has also been reported. Individuals resuscitated from VF definitely need an implantable cardiac defibrillator (ICD) but in others there is no consensus regarding therapy. Role of electrophysiology study to provoke ventricular tachycardia or fibrillation is not yet well defined. Radiofrequency ablation of epicardial substrate in right ventricle in Brugada syndrome is also under critical evaluation. In this review we shall discuss historical features, epidemiology, electrocardiographic features, ionic pathogenesis, clinical features and current status of proposed treatment of ER and BrS.

Syncope: risk stratification and clinical decision making

Syncope is a common occurrence in the emergency department, accounting for approximately 1% to 3% of presentations. Syncope is best defined as a brief loss of consciousness and postural tone followed by spontaneous and complete recovery. The spectrum of etiologies ranges from benign to life threatening, and a structured approach to evaluating these patients is key to providing care that is thorough, yet cost-effective. This issue reviews the most relevant evidence for managing and risk stratifying the syncope patient, beginning with a focused history, physical examination, electrocardiogram, and tailored diagnostic testing. Several risk stratification decision rules are compared for performance in various scenarios, including how age and associated comorbidities may predict short-term and long-term adverse events. An algorithm for structured, evidence-based care of the syncope patient is included to ensure that patients requiring hospitalization are managed appropriately and those with benign causes are discharged safely.

Sudden unexplained death in infants and children: the role of undiagnosed inherited cardiac conditions

Sudden unexplained death in childhood is a traumatic event for both the immediate family and medical professionals. This is termed sudden unexplained or arrhythmic death syndrome (SUDS/SADS) for children over 1 year of age while sudden unexplained death in infancy or sudden infant death syndrome (SUDI/SIDS) refers to unexplained deaths in the first year of life. There is increasing evidence for the role of undiagnosed inherited cardiac conditions, particularly channelopathies, as the cause of these deaths. This has far-reaching implications for the family regarding the potential risk to other family members and future pregnancies, providing a challenge not only in the counselling but also in the structured assessment and management of immediate relatives. This review will discuss the cardiac risk involved in sudden unexplained deaths of infants and children, the role of molecular autopsy, family cardiological screening, current management strategies, and future directions in this area.

[Electrical storm in Brugada syndrome successfully treated with isoproterenol. Report of a case]

We report a 22-year-old male who experienced several episodes of syncope within a timeframe of few hours. In the emergency room, multiple ventricular fibrillation episodes where documented along with a type 1 Brugada ECG pattern. Isoproterenol in continuous infusion was started, normalizing the ECG and avoiding further arrhythmia recurrences. The patient was implanted with an automated defibrillator and discharged 3 days after admission.

ABCC9 is a novel Brugada and early repolarization syndrome susceptibility gene

BACKGROUND

Genetic defects in KCNJ8, encoding the Kir6.1 subunit of the ATP-sensitive K(+) channel (I(K-ATP)), have previously been associated with early repolarization (ERS) and Brugada (BrS) syndromes. Here we test the hypothesis that genetic variants in ABCC9, encoding the ATP-binding cassette transporter of IK-ATP (SUR2A), are also associated with both BrS and ERS.

METHODS AND RESULTS

Direct sequencing of all ERS/BrS susceptibility genes was performed on 150 probands and family members. Whole-cell and inside-out patch-clamp methods were used to characterize mutant channels expressed in TSA201-cells. Eight ABCC9 mutations were uncovered in 11 male BrS probands. Four probands, diagnosed with ERS, carried a highly-conserved mutation, V734I-ABCC9. Functional expression of the V734I variant yielded a Mg-ATP IC₅₀ that was 5-fold that of wild-type (WT). An 18-y/o male with global ERS inherited an SCN5A-E1784K mutation from his mother, who displayed long QT intervals, and S1402C-ABCC9 mutation from his father, who displayed an ER pattern. ABCC9-S1402C likewise caused a gain of function of IK-ATP with a shift of ATP IC₅₀ from 8.5 ± 2 mM to 13.4 ± 5 μM (p<0.05). The SCN5A mutation reduced peak INa to 39% of WT (p<0.01), shifted steady-state inactivation by -18.0 mV (p<0.01) and increased late I(Na) from 0.14% to 2.01% of peak I(Na) (p<0.01).

CONCLUSION

Our study is the first to identify ABCC9 as a susceptibility gene for ERS and BrS. Our findings also suggest that a gain-of-function in I(K-ATP) when coupled with a loss-of-function in SCN5A may underlie type 3 ERS, which is associated with a severe arrhythmic phenotype.