Cycle length-dependent repolarization changes during atrial fibrillation in the Brugada syndrome

This is a case report of a patient with Brugada syndrome who developed paroxysmal atrial fibrillation. During the episode, beat-to-beat changes in ventricular repolarization were observed. These changes were a paradoxical ST-segment alteration after a short-coupled ventricular beat. These findings, not reported before, may be helpful for the diagnosis of this syndrome.     

The Brugada syndrome: clinical,electrophysiologic and genetic aspects

This review deals with the clinical, basic and genetic aspects of a recently highlighted form of idiopathic ventricular fibrillation known as the Brugada syndrome. Our primary objective in this review is to identify the full scope of the syndrome and attempt to correlate the electrocardiographic manifestations of the Brugada syndrome with cellular and ionic heterogeneity known to exist within the heart under normal and pathophysiologic conditions so as to identify the cellular basis and thus potential diagnostic and therapeutic approaches. The available data suggest that the Brugada syndrome is a primary electrical disease resulting in abnormal electrophysiologic activity in right ventricular epicardium. Recent genetic data linking the Brugada syndrome to an ion channel gene mutation (SCN5A) provides further support for the hypothesis. The electrocardiographic manifestations of the Brugada syndrome show transient normalization in many patients, but can be unmasked using sodium channel blockers such as flecainide, ajmaline or procainamide, thus identifying patients at risk. The available data suggest that loss of the action potential dome in right ventricular epicardium but not endocardium underlies the ST segment elevation seen in the Brugada syndrome and that electrical heterogeneity within right ventricular epicardium leads to the development of closely coupled premature ventricular contractions via a phase 2 reentrant mechanism that then precipitates ventricular tachycardia/ventricular fibrillation (VT/VF). Currently, implantable cardiac defibrillator implantation is the only proven effective therapy in preventing sudden death in patients with the Brugada syndrome and is indicated in symptomatic patients and should be considered in asymptomatic patients in whom VT/VF is inducible at time of electrophysiologic study.     

Brugada syndrome: an unusual cause of convulsive syncope

A patient who presented with a new apparent seizure was found to have abnormal electrocardiographic findings, with classic features of the Brugada syndrome. He had spontaneous episodes of nonsustained ventricular tachycardia, easily inducible ventricular fibrillation at electrophysiological study in the absence of structural heart disease, and a negative neurological evaluation. These findings suggested that sustained ventricular arrhythmias known to be associated with the Brugada syndrome and resultant cerebral hypoperfusion, rather than a primary seizure disorder, were responsible for the event. Patients with the Brugada syndrome often present with sudden death or with syncope resulting from ventricular arrhythmias. In consideration of its variability in presentation sometimes mimicking other disorders, primary care physicians and internists should be aware of its often transient electrocardiographic features.     

Localized and dynamic repolarization alternans in Ajmaline accentuated Brugada syndrome

We performed incremental atrial pacing immediately after Ajmaline infusion in an asyntomatic female patient whose basal ECG was suggestive of Brugada Syndrome. Ajmaline accentuated the BS ECG pattern. Incremental Atrial pacing induced localized and dynamic repolarization alternans and unequal diastolic intervals (TQ intervals). No ventricular rhythms were elicited (other than short-coupled, monomorphic, low-density ventricular beats.     

Electrocardiographic and electrophysiologic characteristics in patients with Brugada type electrocardiogram and inducible ventricular fibrillation: single center experience.

BACKGROUND: The study examined the electrocardiographic and electrophysiologic characteristics in relation to programmed ventricular stimulation (PVS)-induced ventricular fibrillation (VF) in patients with Brugada syndrome. METHODS AND RESULTS: Thirty-four patients with a Brugada-type electrocardiogram (ECG) were enrolled. Twelve patients had a type 1 ECG, 12 had a type 2 ECG, and 10 had a type 3 ECG. PVS was performed with up to 2 ventricular premature beats from the right ventricular apex and outflow tract at 2 basic cycle lengths (600 and 400 ms). VF was induced in 17 of 23 (74%) asymptomatic patients and 10 of 11 (91%) symptomatic patients (p<0.05). The 27 patients in whom VF was induced by PVS and 7 patients without inducible VF were followed up for 47.1+/-33.7 months. One sudden death occurred during the follow-up period among asymptomatic patients with inducible VF, and no sudden death occurred among patients without inducible VF. CONCLUSIONS: In conclusion, inducibility of ventricular arrhythmia is high in patients with Brugada syndrome, but it does not correlate with clinical presentation. Few arrhythmic events occur during follow up. However, the present study data suggest that electrophysiologic study-induced VF does not predict arrhythmic events during follow up.     

Recurrent ventricular fibrillation in a patient with Brugada syndrome successfully treated with procainamide

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.     

Brugada syndrome

The Brugada syndrome is a clinical-electrocardiographic diagnosis characterized by syncopal episodes or sudden death (caused by ventricular tachycardia and ventricular fibrillation) in patients with a structurally normal heart with a characteristic electrocardiographic pattern consisting of ST segment elevation in precordial leads (Vl-V3) and a morphology of the QRS complex resembling right bundle branch block (the latter can transiently disappear). Timely diagnosis and adequate treatment may essentially decrease mortality of this disease. In our review we have summarized results of recent studies of etiology, pathogenesis, clinical picture, diagnosis and treatment of the Brugada syndrome.     

Natural history of Brugada syndrome: the prognostic value of programmed electrical stimulation of the heart

INTRODUCTION: The prognostic value of electrophysiologic studies in individuals with the syndrome of right bundle branch block and ST segment elevation in precordial leads V1 to V3 (Brugada syndrome) remains controversial. Our previous data from 252 individuals with the syndrome suggested that programmed ventricular stimulation had a good overall accuracy to predict events. However, studies from independent investigators questioned our results. We report here the largest population with Brugada syndrome ever studied by programmed electrical stimulation of the heart. METHODS AND RESULTS: Four hundred forty-three individuals with an ECG diagnostic of Brugada syndrome were studied by programmed electrical stimulation of the heart. The diagnosis was made because of the classic ECG showing a coved-type ST segment elevation in precordial leads V1 to V3. Of the 443 individuals, 180 had developed spontaneous symptoms (syncope or aborted sudden cardiac death) and 263 were asymptomatic at the time the diagnosis was made. The ventricular stimulation protocol included a minimum of two basic pacing cycle lengths with two ventricular premature beats from the right ventricular apex. A sustained ventricular arrhythmia was induced in 217 cases (49%). Symptomatic patients were more frequently inducible [126/180 (70%)] than asymptomatic individuals [91/263 (34%); P = 0.0001]. Males were more frequently inducible than females (54% vs 32%, P < 0.0001). Inducible individuals had a longer HV interval than noninducible patients (50 +/- 12 msec vs 46 +/- 10 msec, P < 0.002). HV interval and number of premature beats needed to induce VF were not related to outcome. Inducibility was statistically a powerful predictor of arrhythmic events during follow-up. Sixty of 217 inducible patients (28%) had spontaneous ventricular fibrillation compared with 5 of 221 noninducible patients (2%; P = 0.0001). CONCLUSION: Inducibility of sustained ventricular arrhythmias during programmed ventricular stimulation of the heart is a good predictor of outcome in Brugada syndrome.     

Intravenous administration of class I antiarrhythmic drugs induced T wave alternans in a patient with Brugada syndrome

A 71-year-old man who experienced aborted sudden death was referred to our hospital. Coronary artery disease and cerebral accident were ruled out by conventional tests. The 12-lead ECG obtained at rest showed a right bundle branch block pattern and ST segment elevation in leads V1 to V3. Double ventricular extrastimuli at coupling intervals >180 msec induced ventricular fibrillation (VF) twice during electrophysiologic study. Intravenous administration of procainamide accentuated ST segment elevation in leads V1 to V3, and visible T wave alternans was induced in leads V2 and V3 at a dose of 450 mg. Initiation of T wave alternans was not associated with changes of the cardiac cycle or development of premature beats. When procainamide infusion was discontinued, T wave alternans disappeared before the elevated ST segment returned to the control level. Pilsicainide also accentuated ST segment elevation and induced similar T wave alternans in leads V2 and V3. Class I antiarrhythmic drug-related T wave alternans has been reported rarely in Brugada syndrome, but it may represent enhanced arrhythmogenicity of VF. We need to monitor closely and study the clinical implications of T wave alternans in Brugada syndrome.     

Ablação epicárdica para prevenção da fibrilhação ventricular em doente com síndrome de Brugada

We present the case of a 60‐year‐old woman with Brugada syndrome, permanent type 1 electrocardiographic pattern, who had previously received an implantable cardioverter‐defibrillator. She suffered frequent syncopal episodes and multiple appropriate shocks (around five per month) due to polymorphic ventricular tachycardia/ventricular fibrillation, refractory to quinidine therapy. Combined epicardial and endocardial electroanatomical mapping was performed with a view to substrate ablation. An area of abnormal fractionated electrograms, lasting up to 370 ms and up to 216 ms after the end of the surface QRS, was identified in the epicardium in the lower anterior part of the right ventricular outflow tract. Extensive epicardial ablation of this area, which eliminated the fractionated electrograms, led to the disappearance of the Brugada electrocardiographic pattern six weeks after ablation. Despite discontinuation of quinidine, no further ventricular arrhythmias occurred during follow‐up, which is still of short duration.     

Current electrocardiographic criteria for diagnosis of Brugada pattern: a consensus report

Brugada syndrome is an inherited heart disease without structural abnormalities that is thought to arise as a result of accelerated inactivation of Na channels and predominance of transient outward K current (I(to)) to generate a voltage gradient in the right ventricular layers. This gradient triggers ventricular tachycardia/ventricular fibrillation possibly through a phase 2 reentrant mechanism. The Brugada electrocardiographic (ECG) pattern, which can be dynamic and is sometimes concealed, being only recorded in upper precordial leads, is the hallmark of Brugada syndrome. Because of limitations of previous consensus documents describing the Brugada ECG pattern, especially in relation to the differences between types 2 and 3, a new consensus report to establish a set of new ECG criteria with higher accuracy has been considered necessary. In the new ECG criteria, only 2 ECG patterns are considered: pattern 1 identical to classic type 1 of other consensus (coved pattern) and pattern 2 that joins patterns 2 and 3 of previous consensus (saddle-back pattern). This consensus document describes the most important characteristics of 2 patterns and also the key points of differential diagnosis with different conditions that lead to Brugada-like pattern in the right precordial leads, especially right bundle-branch block, athletes, pectus excavatum, and arrhythmogenic right ventricular dysplasia/cardiomyopathy. Also discussed is the concept of Brugada phenocopies that are ECG patterns characteristic of Brugada pattern that may appear and disappear in relation with multiple causes but are not related with Brugada syndrome.     

Brugada综合征患者的心电图及临床特点分析

目的分析Brugada综合征患者的心电图及临床特点。方法对我院近5年诊断的8例Brugada综合征住院患者的心电图及临床情况进行长期随访观察。结果8例Brugada综合征患者均为男性，年龄平均（40±13）岁。心电图Ⅰ型Brugada波者3例，Ⅱ型4例，Ⅲ型1例；Brugada波具有多变性，提高肋间描记右胸导联心电图可显现Brugada波或使其更明显。8例中4例有猝死家族史，5例有晕厥史，3例在住院期间发生室速／室颤，随访期间2例猝死。结论心电图Brugada波（尤其Ⅰ型）是诊断Brugada综合征的必要条件，明确诊断Brugada综合征尚需联合其他几项临床指标；Brugada综合征患者猝死的风险高，消除晕厥或室速／室颤的诱因是预防的关键。     

Prevalence of Brugada sign in patients presenting with palpitation in southern Iran.

AIMS: Brugada syndrome is a cardiac channel abnormality that is associated with a high risk of ventricular fibrillation and sudden cardiac death and characterized by an electrocardiographic pattern of right bundle branch block and transient or persistent ST-segment elevation in leads V1-V3. No data regarding the frequency of Brugada syndrome exist in an Iranian population. The aim of this study was to determine the frequency of Brugada-type ECG pattern in southern Iran. METHODS AND RESULTS: All patients presenting with palpitation were enrolled in the study. A Brugada-type ECG pattern was determined according to the criteria recommended by European Heart Association Molecular Basis of Arrhythmias Study Group. A total of 3895 patients (mean age 38.2 +/- 11.9 years, 54% women) met all study criteria. One hundred patients (2.56%) had Brugada-type ECG pattern. Of these, 21 patients (0.54%) had definite Brugada sign (Type 1 or Types 2 and 3 with conversion to Type 1 following procainamide test). Of 21 patients with definite Brugada sign, eight had Brugada syndrome, four had history of syncope, two had coved-type ECG in the family, one had polymorphic ventricular tachycardia, and one had history of sudden cardiac death in the family. Five patients underwent ICD implantation. The incidence of a Brugada-type ECG pattern was 2.43% in subjects between 17 and 30 years and 0.13% in subjects >30 years (P = 0.01). CONCLUSION: Frequency of Brugada sign in an Iranian population presenting with palpitation is greater than some European countries and lower than a Japanese urban population.     

Is there an overlap between Brugada syndrome and arrhythmogenic right ventricular cardiomyopathy/dysplasia?

The Brugada syndrome is a congenital syndrome displaying an autosomal dominant mode of transmission in patients with a structurally normal heart. The disease has been linked to mutations in SCN5A , a gene located on the short arm of chromosome 3 (p21-24) that encodes for the alpha subunit of the sodium channel. The syndrome is characterized by a dynamic ST-segment elevation (accentuated J wave) in leads V 1 to V 3 of the ECG followed by negative T wave. Right bundle-branch block of varying degrees is observed in some patients. The syndrome is associated with syncope and a relatively high incidence of sudden cardiac death secondary to the development of polymorphic ventricular tachycardia that may degenerate into ventricular fibrillation. An acquired form of the Brugada syndrome is also recognized, caused by a wide variety of drugs and conditions that alter the balance of currents active during the early phases of the action potential. Among patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia, there is a subpopulation with a clinical and electrocardiographic pattern similar to that of the Brugada syndrome. These cases of arrhythmogenic right ventricular cardiomyopathy/dysplasia are thought to represent an early or concealed form of the disease. This review examines the overlap between these 2 syndromes.     

Right ventricular electrocardiographic leads for detection of Brugada syndrome in sudden unexplained death syndrome survivors and their relatives

BACKGROUND: Sudden unexplained death syndrome (SUDS) is a sudden death syndrome in previously healthy Southeast Asian young adults without any structural causes of death. Many SUDS survivors show electrocardiographic (ECG) evidence of RSR' and ST elevation in leads V1 to V3, which is similar to the ECG pattern in Brugada syndrome. However, in many cases transient normalization of the ECG does not make diagnosis with standard 12-lead ECG possible. HYPOTHESIS: To overcome this problem, we utilized the new right ventricular ECG leads to detect the Brugada syndrome in SUDS survivors. METHODS: The subject was a Thai male patient who presented with a SUDS-like syncopal attack. He had cardiac arrest due to idiopathic ventricular fibrillation. RESULTS: Post-resuscitation standard 12-lead ECG showed no diagnostic features of Brugada syndrome. However, ECG patterns of RSR' and ST elevations typical for Brugada syndrome could be detected at the higher intercostal space leads V1 to V3. We observed similar findings in 2 of the other 10 SUDS survivors and 4 of 23 healthy family members. CONCLUSIONS: Our data suggest that these new right ventricular leads ECG may be helpful in detecting Brugada syndrome in SUDS survivors and their relatives.     

J-wave syndromes. from cell to bedside

The J wave, a deflection that follows the QRS complex of the surface electrocardiogram, is usually partially buried in the R wave in humans, appearing as a J-point elevation. An early repolarization (ER) pattern characterized by J-point elevation, slurring of the terminal part of the QRS, and ST-segment elevation has long been recognized and considered to be totally benign. Recent studies have presented evidence demonstrating that an ER pattern in inferior leads or inferolateral leads is associated with increased risk for life-threatening arrhythmias, named early repolarization syndrome. Early repolarization syndrome and Brugada syndrome share similar electrocardiographic characteristics, clinical outcomes, risk factors, as well as a common arrhythmic platform related to amplification of I_to-mediated J waves. Although Brugada syndrome and early repolarization syndrome differ with respect to the magnitude and lead location of abnormal J wave manifestation, they can be considered to represent a continuous spectrum of phenotypic expression, termed J-wave syndromes. Early repolarization syndrome has been proposed to be divided into 3 subtypes: type 1, displaying an ER pattern predominantly in the lateral precordial leads, is prevalent among healthy male athletes and rarely seen in ventricular fibrillation survivors; type 2, displaying an ER pattern predominantly in the inferior or inferolateral leads, is associated with a higher level of risk; whereas type 3, displaying an ER pattern globally in the inferior, lateral, and right precordial leads, is associated with the highest level of risk for development of malignant arrhythmias and is often associated with ventricular fibrillation storms.     

Mode of onset of ventricular fibrillation in patients with Brugada syndrome detected by implantable cardioverter defibrillator therapy

OBJECTIVES: We sought to demonstrate the mode of spontaneous onset of ventricular fibrillation (VF) in patients with Brugada syndrome. BACKGROUND: The electrophysiologic mechanisms of VF in Brugada syndrome have not been fully investigated. METHODS: Nineteen patients (all male, mean age 47 +/- 12 years) with Brugada syndrome were treated with an implantable cardioverter defibrillator (ICD). The implanted devices were capable of storing electrograms during an arrhythmic event. We investigated the mode of spontaneous onset of VF according to the electrocardiographic features during the episode of VF, which were obtained from stored electrograms of ICDs and/or electrocardiographic (ECG) monitoring. RESULTS: During a follow-up of 34.7 +/- 19.4 months (range 14 to 81 months), 46 episodes of spontaneous VF attacks were documented in 7/19 (37%) patients. The event-free period between ICD implantation and the first spontaneous occurrence of VF was 14.6 +/- 12.1 months (range 3.7 to 27.4 months). We investigated 33/46 episodes of VF, for which electrocardiographic features (10 to 20 s before and during VF) were obtained from ICDs and/or ECG monitoring in five patients. A total of 22/33 episodes of VF were preceded by premature ventricular contractions (PVCs), which were almost identical to the initiating PVCs of VF. Furthermore, in three patients who had multiple VF episodes, VF attacks were always initiated by the same respective PVC. The coupling interval of the initiating PVCs of VF was 388 +/- 28 ms. CONCLUSIONS: Spontaneous episodes of VF in patients with Brugada syndrome were triggered by specific PVCs. These findings may provide important insights into the pathophysiological mechanisms causing VF in Brugada syndrome.     

Early repolarization syndrome: is it always benign?

Early repolarization syndrome is a well-recognized idiopathic electrocardiographic phenomenon characterized by prominent J wave and ST-segment elevation predominantly in left precordial leads. The syndrome shares remarkable cellular, ionic, and electrocardiographic similarities with the Brugada syndrome and idiopathic ventricular fibrillation (a variant of the Brugada syndrome with ST-segment elevation in inferior leads). Although early repolarization syndrome is considered a benign entity, its arrhythmogenic potential still remains unknown. We report the case of a 39-year-old male with a family history of sudden death and an electrocardiogram consistent with early repolarization syndrome. Diagnostic dilemmas are discussed.     

Síncope em contexto febril – caso clínico de síndrome de Brugada

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.     

Ventricular Fibrillation in Type B Wolff-Parkinson-White Syndrome

Summary: A patient with type B Wolff-Parkinson-White syndrome developing recurrent ventricular fibrillation is presented. Frequent ventricular premature beats preceded the onset of ventricular fibrillation which occurred on five occasions. A combination of lignocaine, practolol, procaineamide and atrial pacing suppressed the recurrence of ventricular premature beats and ventricular fibrillation.