The Brugada Syndrome

The Brugada syndrome is a genetically determined disease caused by mutations of the cardiac sodium channel. The disease affects mainly males in their forties and causes sudden cardiac death because of polymorphic ventricular tachycardia. These patients have a structurally normal heart. The electrocardiogram of this syndrome shows, spontaneously or after Class 1 antiarrhythmic drugs, ST segment elevation in leads V₁ to V₃ and a pattern resembling a right bundle branch block. Phase 2 reentry between epi‐ and endocardiac layers is responsible for the arrhythmias. The only effective treatment at present is implantation of a cardioverter defibrillator. A.N.E. 2000;5(1):88–91     

The Brugada Syndrome

In 1992 a syndrome was described consisting of syncopal episodes and/or (resuscitated) sudden death in patients with a structurally normal heart and a characte ristic electrocardiogram (ECG) displaying a pattern resembling a right bundle branch block with ST segment elevation in leads V1 to V3. The disease is genetically determined with an autosomal dominant pattern of transmission in 50% of the familial cases. Several different mutations have been identified affecting the structure, function and trafficking of the sodium channel. The syndrome is ubiquitous. Its incidence and prevalence are difficult to estimate, but this disease may cause 4 to 10 sudden deaths per 10,000 inhabitants per year representing the most frequent cause of natural death in males younger than 50 in South Asia. The disease has been linked to the sudden infant death syndrome (SIDS) and to the sudden unexpected death syndrome (SUDS) by showing that the electrocardiogram and mutations are the same as in Brugada syndrome. The diagnosis is easily made by means of the ECG when it is typical. There exist, however, patients with concealed and intermittent electrocardiographic forms that make the diagnosis difficult. The ECG can be modulated by changes in autonomic balance, body temperature, glucose level and the administration of antiarrhythmic, neuroleptic and antimalaria drugs. Beta adrenergic stimulation normalizes the ECG. Loss of the action potential dome in right ventricular epicardium but not in endocardium underlies the ST segment elevation. Electrical heterogeneity within right ventricular epicardium leads to the development of closely coupled extrasystoles via phase 2 reentry that precipitate ventricular ,fibrillation. Antiarrhythmic drugs do not prevent sudden death in symptomatic or asymptomatic individuals. Implantation of an automatic cardioverter-defibrillator is the only currently proven effective therapy. Patients with frequent electrical storms may even need cardiac transplantation as last resort.     

Brugada Syndrome and Idiopathic Left Ventricular Tachycardia Unmasked by Exercise and a Class Ic Drug

The patient was a 33-year-old male. Twenty years ago, he underwent radiofrequency catheter ablation for idiopathic sustained monomorphic ventricular tachycardia (VT) with an RBBB and superior axis pattern. The VT was inducible by programmed stimulation and entrained by rapid pacing. At this presentation, he developed palpitation and VT with the same morphology at the peak exercise on a treadmill with appearance of typical ECG pattern for Brugada syndrome (BrS). Pilsicainide induced the typical ECG pattern and premature ventricular beats (PVBs) of the same morphology as VT. The relationship between BrS and VT of left ventricular origin was discussed.     

电生理检查在Brugada综合征危险分层中的价值

Brugada综合征是一种遗传性心律失常疾病,约1/3的患者是由于心脏离子通道基因,主要是SCN5A基因的突变所致。患者可表现出各种心律失常,包括室上性心动过速、房室传导延缓或阻滞、室性心动过速     

Diagnosis and management of Brugada Syndrome

Brugada Syndrome (BS) is a cardiac ion channel disorder linked to loss of function mutation in the SCN5A gene which affects the sodium current. The diagnosis is made on the ECG showing characteristic cove-shaped ST elevation in leads V(1) to V(3) in the absence of structural heart disease, electrolyte disturbance or ischaemia. This condition is genetically transmitted as an autosomal dominant syndrome with incomplete penetrance. It is responsible for 20% of all sudden deaths in those without structural heart disease. Diagnosis of BS can be difficult as the ECG changes are dynamic and variable. Genetic mutation in SCN5A gene is found in 25-30% of patients with Brugada Syndrome. Patients may present with syncope due to polymorphic VT or resuscitated sudden death in the third or fourth decade of life. Symptoms frequently occur at night or at rest and fever is a common trigger in children. Patients presenting with syncope or resuscitated sudden cardiac death should have an implantable defibrillator. Management of asymptomatic patients is controversial and risk stratification is required. www.brugadadrugs.org gives a list of drugs that should be avoided by patients suffering from BS.     

第15课变异型Brugada综合征

近年来,特发性心室颤动(VF)伴有特征性的心电图表现(右束支传导阻滞和右胸前导联ST段抬高)受到关注,自从1992年Brugada等首次报道后,上述表现已被称之谓Bru-gada综合征。最近报道了Brugada综合征的变异型,3例为日本患者和1例为越南患者。与那些(典型)Brugada综合征不同的是:他们的心电图不是在右胸前导联,而是在下壁导联显示J波和ST段抬高。然而,其他的特点十分相似。这4例患者有非常相似的如下特征:①4例患者均为男性,②所有患者均在夜间或清晨经历过数次晕厥或心脏停搏,③动态心电图显示偶发或没有室性期前收缩,④注射丙吡胺使其中3…     

Brugada综合征若干临床进展

Brugada综合征是一遗传性致心律失常疾病,显示右心前导联(V_1~V_2)ST段抬高与T波倒置,而心脏结构正常。易发生心室颤动和心脏性猝死。晕厥、夜间濒死性呼吸和心脏停搏是其常见症状。近年来,Brugada综合征的研究取得了一些进展:如揭示隐匿性Brugada 1型心电图的方法,除了药物实验外,还发现将右心前导联放置在第2肋间;用24小时动态心电图监测;早期复极(J波)对Brugada综合征预后判断有很大价值。以前,射频导管消融只针对右室流出道的外膜,现在右室流出道内膜也可做射频导管消融。     

药物性Brugada样心电图/综合征

Brugada综合征以心电图上右胸导联ST段抬高和心脏性猝死为特征,是一种遗传性心电疾病。近年来发现多种非心血管疾病领域的药物,如抗精神病药、麻醉药、抗组胺药等在常规或过量使用时,可引起心电图呈Brugada样改变,少数患者可在此基础上发生恶性心律失常等心脏事件。临床医生应充分认识这些药物的电生理效应及其可能的后果并给予足够的重视。     

Spontaneous Fluctuations between Diagnostic and Nondiagnostic ECGs in Brugada Syndrome Screening: Portuguese Family with Brugada Syndrome

Background: All family members of patients with Brugada syndrome (BS) should be screened. Fluctuations between diagnostic and nondiagnostic electrocardiogram (ECG) patterns in patients with BS are recognized, but systematic studies are lacking. The objective of this work was to prospectively evaluate the spontaneous changes between diagnostic and nondiagnostic ECG patterns in a family screened for BS. Methods: One hundred twenty‐nine family members were possibly affected plus the index case were screened with two ECGs with an interval of 6 months. Only coved‐type ECG pattern was defined as diagnostic; type 2 and 3 ECGs were considered suggestive. Results: The first ECG series made six diagnostics and the second 11, but only three patients maintained the diagnostic ECG. Patients with basal diagnostic ECG were older and more frequently symptomatic. Body mass index (BMI) was significantly lower in adults with diagnostic plus suggestive ECG when compared with the others. No significant gender difference was found among relatives with or without diagnostic ECG. Conclusion: Spontaneous phenotypic manifestation of BS was more frequent in older symptomatic patients, absent in children, and related with low BMI. ECG manifestations were intermittent in more than 3/4 of the affected patients. Fluctuations between diagnostic and nondiagnostic ECGs may have an implication on the correct phenotyping in family screening so several ECGs with drug challenging are mandatory. Ann Noninvasive Electrocardiol 2010;15(4):337‐343     

The Brugada Syndrome: Facts and Controversies

The diagnosis of Brugada syndrome (BS) is based on a combination of clinical (malignant arrhythmias presenting as syncopal or sudden death episodes) and electrocardiographic (pathognomonic ST segment elevation morphology) features. Over the last 15 years, since its introduction as a distinct clinical entity, the BS has been extensively investigated worldwide. In this article an overview of recent developments concerning the genetic background, the diagnostic tools and the therapeutic alternatives will be presented. In the last years, the results of the first medium-term follow-up studies have also been published. Some of these studies present contradictory results, especially concerning the identification of useful sudden death predictors in asymptomatic patients. The review presented here will discuss this prognostic controversy and will offer possible explanations for the different results.     

Risk Stratification and Treatment of Brugada Syndrome

Takayasu arteritis (TA) is 1 of the 2 main causes of large vessel vasculitides (LVV), giant cell arteritis being the other. LVV can also develop in various other systemic diseases. In TA, a wide variety of symptoms result from vascular stenoses, occlusions, and dilation. Aneurysms may develop and may occasionally dissect or rupture. Disease activity can sometimes be difficult to assess clinically. Diagnostic modalities also have their shortcomings. Often, acute phase reactants do not accurately detect disease activity. Available vascular imaging modalities may be acceptable in defining vascular anatomy, but are notoriously inaccurate in delineating vascular inflammation. Glucocorticoids remain the cornerstone of therapy in TA, in spite of foreseeable long term side effects. In addition, several steroid-sparing agents are also being used, often based on promising results from small uncontrolled studies. Rarely, endovascular revascularization procedures are necessary. Resection of critical-sized aortic aneurysms and repair of aortic dissections are occasionally warranted as lifesaving procedures. The long term outcome of surgical intervention is often unfavorable and relapses are not uncommon. In addition to TA, other less commonly encountered causes of LVV are also briefly discussed in this review.     

Electrophysiological Basis and Genetics of Brugada Syndrome

Brugada syndrome is a primary arrhythmic syndrome arising in the structurally normal heart. Any proposed mechanism should account for the major features of the syndrome: localization of the ST segment and T-wave changes to the right precordial leads, association of conduction slowing at several levels, precipitation or aggravation of the major ECG changes by sodium channel-blocking drugs and the occurrence of ventricular fibrillation. Heterogeneity of repolarization across the ventricle wall plays a major role. Any agency that shifts the net current gradient during phase I outward would exaggerate the normal heterogeneity of repolarization and result in the ST segment and T-wave changes characteristic of the syndrome. When the outward current shift is marked, premature repolarization may occur in epicardial zone and the resulting gradient may precipitate reentry. The syndrome is inherited as an autosomal dominant. However, 75% of clinically affected individuals are males. In 20% of cases, the syndrome is associated with mutations of the cardiac sodium channel gene SCN5A. The mutations result in a loss-of-function as a result of the synthesis of a non-functional protein, altered protein trafficking, or change in gating. Agencies that reduce the sodium current may precipitate the characteristic ECG changes, for example, sodium channel blockers and membrane depolarization by hyperkalemia. Sympathetic stimulation may reverse the ECG changes and reduce arrhythmia recurrence. By its nonspecific potassium channel blocking action, quinidine may also reduce arrhythmia recurrence. We still do not know the basis for defect in the majority of patients with Brugada syndrome.     

Brugada综合征临床研究进展

1992年西班牙学者 Brugada[1]首先报导一组因特异性室速 ( VT)导致猝死的患者 ,其体表心电图 ( ECG)表现为右束支传导阻滞 ( RBBB) ,伴右胸导联 ST段抬高的病征 ,而命名为 Brugada综合征 ,其临床意义在于患者有多源性室早及持续性 VT、室颤 ( VF)而致死亡。近年来 ,世界多个国家均有报导 ,发病主要分布在东南亚 ,尤其在日本和泰国 ,已成为青年人猝死主要原因[2 ] 。我国目前已报导 3例[3-5] 。现将有关此综合征的临床研究进展作一综述。1　临床特征Brugada综合征首先是从一位 3岁患儿发现的[1] ,此前病儿先后几次发生 VF而行复苏治…