Brugada Phenocopy Induced by Electrolyte Disorder: A Transient Electrocardiographic Sign

Brugada syndrome (BrS) is an important cause of sudden cardiac death (SCD) with well‐defined ST‐segment elevation patterns on V₁–V₃. Observation of BrS‐Type‐electrocardiogram (ECG) patterns in medical conditions without true BrS is called “Brugada Phenocopy” (BrP). We present a case of 61‐year‐old male patient with hyperkalemia, hyponatremia, and BrS‐Type‐1 ECG pattern in the setting of acute postrenal failure. He was denying any syncope or family history of SCD. With normalization of electrolyte levels, BrS‐Type‐1‐ECG resolved. Electrolyte disturbances are one of the most common reasons of BrP. Being aware of BrPs and differentiating from an unmasked BrS‐ECG pattern could prevent patients from lethal consequences and unnecessary treatments.     

Brugada Phenocopy in a Patient with Pectus Excavatum: Systematic Review of the ECG Manifestations Associated with Pectus Excavatum

Brugada phenocopies (BrP) have emerged as new clinical entities that are etiologically distinct from true Brugada syndrome (BrS). BrP are characterized by an ECG pattern that is phenotypically identical to true BrS (type 1 or type 2); however, BrP are caused by various other factors such as mechanical mediastinal compression, myocardial ischemia, pericarditis, myocarditis, pulmonary embolism, and metabolic disturbances. We report a case of an electrocardiographic BrP in a patient with pectus excavatum deformity in the absence of true BrS using currently defined BrP diagnostic criteria. A systematic review of ECG manifestations associated with pectus excavatum is also discussed.     

Brugada phenocopy: A new electrocardiogram phenomenon

Brugada phenocopies(BrP) are clinical entities that are etiologically distinct from true congenital Brugada syndrome. BrP are characterized by type 1 or type 2 Brugada electrocardiogram(ECG) patterns in precordial leads V1-V3. However, BrP are elicited by various un-derlying clinical conditions such as myocardial ischemia, pulmonary embolism, electrolyte abnormalities, or poor ECG filters. Upon resolution of the inciting underlying pathological condition, the BrP ECG subsequently nor-malizes. To date, reports have documented BrP in the context of singular clinical events. More recently, recur-rent BrP has been demonstrated in the context of re-current hypokalemia. This demonstrates clinical repro-ducibility, thereby advancing the concept of this new ECG phenomenon. The key to further understanding the pathophysiological mechanisms behind BrP requires experimental model validation in which these phenom-ena are reproduced under strictly controlled environ-mental conditions. The development of these validation models will help us determine whether BrP are tran-sient alterations of sodium channels that are not repro-ducible with a sodium channel provocative test or al-ternatively, a malfunction of other ion channels. In this editorial, we discuss the conceptual emergence of BrP as a new ECG phenomenon, review the progress made to date and identify opportunities for further investiga-tion. In addition, we also encourage investigators that are currently reporting on these cases to use the term BrP in order to facilitate literature searches and to help establish this emerging concept.     

Type 1 electrocardiographic burden is increased in symptomatic patients with Brugada syndrome

Background

Spontaneous type 1 electrocardiographic (ECG) is a risk factor for arrhythmic events in Brugada patients but the importance of the proportion of time with a type 1 ECG is unknown.

Patients and Methods

Thirty-four Brugada patients (15 symptomatic) underwent a 24-hour 12-lead ECG recording. One-minute averaged waveforms displaying ST-segment elevation above 200 μV, with descending ST-segment and negative T-wave polarity on leads V₁-V₃ were considered as type 1 Brugada ECG. The burden was defined as the percentage of type 1 Brugada waveforms.

Results

Type 1 ECG on lead V2 was more frequent in symptomatic patients (median 80.6% [15.7-96.7] vs 12.4% [0.0-69.7], P = .05). Patients with a permanent type 1 pattern on lead V₂ were more likely to be symptomatic (5/6) than patients without type 1 ECG during a 24-hour period (2/9) (P < .05).

Conclusion

Type 1 pattern is more prevalent across a 24-hour period in symptomatic Brugada patients.     

Brugada phenocopy associated with left ventricular aneurysm

Brugada phenocopies (BrP) are clinical entities that are characterized by ECG patterns identical to those of Brugada syndrome, but are the result of various clinical conditions. We describe the case of a 41-year-old male who exhibited BrP due to a left ventricular aneurysm in the context of chronic coronary artery disease.     

Type 1 Brugada phenocopy in a patient with acute pericarditis

We herein describe a case of an acute pericarditis, in which type 1 Brugada phenocopy (BrP) was documented. The patient was referred to our hospital due to severe chest pain. The twelve-lead electrocardiogram (ECG) on admission showed type 1 Brugada ECG pattern (coved-type) in the precordial leads. Echocardiography only showed mild pericardial effusion. However, his ST segment elevation returned to normal and chest discomfort disappeared 3?weeks later. Our report addresses the possibility that the coved-type ST-segment elevation cannot be a sensitive finding for Brugada syndrome (BrS). Detailed tests are anyway needed to make appropriate diagnostic and therapeutic decisions.     

Spontaneous alternans in Brugada ST-segment morphology within minutes

Brugada syndrome is an inherited, life-threatening, cardiac channelopathy where the electrocardiogram (ECG) characteristically depicts a classic pattern of complete or incomplete right bundle-branch block with ST-segment elevation in the right precordial leads V₁ to V₃. These, almost inalienable, ECG patterns may be dynamic, where changes may resolve to baseline or one particular type may evolve into another. Such alternans has been described with fever, electrolyte imbalances, atrial pacing, glucose and/or insulin administration, psychotropic drugs, β-adrenergic blocker use, class IA and IC antiarrhythmic provocation testing, such as with ajmaline, procainamide, or flecainide, and even large meals, that is, “full stomach sign.” However, spontaneous alternans between the different types of Brugada ECG patterns (types) have not been reported within minutes, in the absence of previously described precipitating factors. We present a novel case where classic, type 2, Brugada-like ECG pattern evolved spontaneously to type 1 before returning to type 2 within minutes of presentation.     

Low prevalence of Brugada-type electrocardiogram in a prospective large cohort of Egyptians

BackgroundBrugada syndrome is a cardiac channelopathy that is associated with a high risk of VF and SCD and characterized by ECG pattern of transient or persistent, coved type ST-segment elevation in leads V₁–V₃.AimTo prospectively determine the prevalence of Brugada-type ECG pattern (Brugada sign) among unselected non cardiac individuals served at Cairo university teaching-hospital.MethodsThis study was conducted from October 2011 to September 2012, and included 4000 unselected noncardiac individuals (2078 males 52%, mean age 39 ± 14.44 years) admitted or presented to our hospital for different reasons. A 12-lead ECG was recorded for each of them; these ECGs were reviewed independently by two electrophysiologists for criteria of the three types of Brugada ECG pattern, and diagnosis of Brugada sign was made when both investigators agreed on the classification of the ECG findings according to the criteria of the Consensus Report of the Study Group of the Molecular Basis of Arrhythmia of the European Society of Cardiology.ResultsTwenty-two (0.55%) subjects had Brugada ECG pattern. All of them were of Mediterranean ethnic group. 18 males (0.45%), and 4 females (0.1%). No subjects showed type-1, while 11 (0.275%) of the 22 subjects had type-2, and the other 11 had type-3 Brugada ECG pattern. Eight cases (0.2%) among the 22 subjects were between 10 and 24 years old. Of the 22 subjects, 4 cases (18.2%) were symptomatic (palpitation and syncope), and 3 cases (13%) had positive F.H of SCD.ConclusionThe frequency of type-1 Brugada-type ECG pattern was 0%, while type-2 and type-3 (saddleback type) was 0.55% among Egyptian hospital-based population, and it was more prevalent in middle-aged males.     

Brugada electrocardiographic pattern due to tricyclic antidepressant overdose

The Brugada syndrome is an arrhythmogenic disease with characteristic coved ST-segment elevation 2 mm or greater in the right precordial leads (type 1 Brugada electrocardiogram [ECG] pattern or “Brugada sign”] and is estimated to be responsible for at least 20% of sudden deaths in patients with structurally normal hearts [Circulation 2005;111(5):659-70]. The Brugada sign has been described in asymptomatic patients after exposure to various drugs. As published reports of the drug-induced Brugada sign have become increasingly prevalent, there is growing interest in the mechanisms responsible for this acquired ECG pattern and its clinical significance.We report a case of a patient who developed the type 1 Brugada ECG pattern after intentional overdose of a tricyclic antidepressant agent, review the literature concerning tricyclic antidepressant agent-induced Brugada sign, discuss potential mechanisms, and evaluate the clinical significance of this ECG abnormality.     

Long‐term prognosis in patients with non‐type 1 Brugada electrocardiogram: Results from a large Japanese cohort of idiopathic ventricular fibrillation

BackgroundBrugada syndrome (BrS) is diagnosed in patients with ST‐segment elevation with spontaneous, drug‐induced, or fever‐induced type 1 morphology. Prognosis in type 2 or 3 Brugada electrocardiogram (Br‐ECG) patients remains unknown. The purpose of this study is to evaluate long‐term prognosis in non‐type 1 Br‐ECG patients in a large Japanese cohort of idiopathic ventricular fibrillation (The Japan Idiopathic Ventricular Fibrillation Study [J‐IVFS]).MethodsFrom 567 patients with Br‐ECG in J‐IVFS, a total of 28 consecutive non‐type 1 patients who underwent programmed electrical stimulation (PES) (median age: 58 years, all male, previous sustained ventricular tachyarrhythmias [VTs] 1, syncope 11, asymptomatic 16) were enrolled. Cardiac events (CEs: sudden cardiac death or sustained VT/ventricular fibrillation) during the follow‐up period were examined.ResultsDuring a median follow‐up of 136 months, four patients (14%) had CEs. None of patients with PES‐ have experienced CEs. There was no statistically significant clinical risk factor for the development of CEs. Using the Kaplan–Meier method, the event‐free rate significantly decreased in a group with all 3 risk factors (symptom, wide QRS complex in lead V₂, and positive PES) (p = .01).ConclusionsOur study revealed long‐term prognosis in patients with non‐type 1 Br‐ECG. The combination analysis of these risk factors may be useful for the risk stratification of CEs in non‐type 1 Br‐ECG patients. The present study suggests that the patients with all these parameters showed high risk for CEs and need to be carefully followed.     

Yellow phosphorus-induced Brugada phenocopy

Background

Metallic phosphides (of aluminum and phosphide) and yellow phosphorus are commonly used rodenticide compounds in developing countries. Toxicity of yellow phosphorus mostly pertains to the liver, kidney, heart, pancreas and the brain. Cardiotoxicity with associated Brugada ECG pattern has been reported only in poisoning with metallic phosphides.

Transient left septal and anterior fascicular block associated with type 1 electrocardiographic Brugada pattern

The left septal fascicular block (LSFB) or blockage of the middle fibers of the left bundle branch is probably caused mainly by - in the developed world - the proximal obstruction of the left anterior descending artery (LAD) before its first anterior septal perforator branch (S₁). The association of transient LSFB and left anterior fascicular block (LAFB) - left bifascicular block - and the electrocardiographic type 1 Brugada pattern (BrP) has not been described in the literature yet.     

Brugada Syndrome: Current Clinical Aspects and Risk Stratification

Brugada syndrome is a primary electrical disease of the heart that causes sudden cardiac death or life‐threatening ventricular arrhythmias, especially in younger men. Genetic analysis supports that this syndrome is a cardiac ion channel disease. A typical electrocardiographic finding consists of a right bundle branch block pattern and ST‐segment elevation in the right precordial leads. The higher intercostal space V₁ to V₃ lead electrocardiogram could be helpful in detecting Brugada patients. Although two types of the ST‐segment elevation are present, the coved type is more relevant to the syndrome than the saddle‐back type. These patterns can be present permanently or intermittently. Recent data suggest that the Brugada‐type electrocardiogram is more prevalent than the manifest Brugada syndrome. Asymptomatic individuals have a much lower incidence of future cardiac events than the symptomatic patients. Although risk stratification for the Brugada syndrome is still incomplete, the inducibility of sustained ventricular arrhythmias has been proposed as a good outcome predictor in this syndrome. In noninvasive techniques, some clinical evidence supports that late potentials detected by signal‐averaged electrocardiography are a useful index for identifying patients at risk. The available data recommend prophylactic implantation of an imptantabie cardioverter defibrillator to prevent sudden cardiac death. This review summarizes recent information of the syndrome by reviewing most of new clinical reports and speculates on its risk stratification. A.N.E. 2002;7(3):251–262     

Differential Diagnosis of rSr’ Pattern in Leads V1‐V2. Comprehensive Review and Proposed Algorithm

One of the more frequent dilemmas in ECG interpretation is the differential diagnosis of an rSr’ pattern in leads V₁‐V₂. We often face this finding in asymptomatic and otherwise healthy individuals and the causes may vary from benign nonpathological variants to severe or life‐threatening heart diseases, such as Brugada syndrome or arrhythmogenic right ventricular dysplasia. In other cases, a normal variant of rSr’ pattern can be misinterpreted as pathological after the occurrence of certain clinical events such as cardiac arrest or syncope of unknown cause. In this review we analyze in detail all the possible conditions, both benign and pathological that may explain the presence of this electrocardiographic pattern. We also propose a simple electrocardiographic algorithm for differential diagnosis.     

Usefulness of Multichannel Holter ECG Recording in the Third Intercostal Space for Detecting Type 1 Brugada ECG: Comparison with Repeated 12-Lead ECGs

Introduction : Type 1 Brugada ECG is essential for the diagnosis of Brugada syndrome. We aimed to evaluate the usefulness of multichannel Holter ECG recording in the third intercostal space for detecting type 1 Brugada ECG.
Methods and Results : We enrolled 60 consecutive individuals with type 1 Brugada ECG and 31 individuals with type 2 or 3 Brugada ECG, in the presence or absence of Na+ channel blockers. All individuals underwent 12-lead ECGs recorded in the standard position and the third intercostal space at least 5 times every 3 months (4L-ECGs, 3L-ECGs, respectively) and multichannel Holter ECG. On multichannel Holter ECG, the precordial electrodes were attached at standard positions (4L-Holter) and the third intercostal space (3L-Holter) for leads V1 and V2. Among the 60 individuals, type 1 Brugada ECG in 4L-ECGs, 3L-ECGs, 4L-Holter, and 3L-Holter was detected in 15 (25%), 26 (43.3%), 23 (38.3%), and 33 individuals (55%), respectively, whereas detected in none of the 31 individuals. The documented duration of type 1 Brugada ECG on 3L-Holter was significantly longer than that on 4L-Holter (700 ± 467 vs 372 ± 422 min; P = 0.01, 3L-Holter vs 4L-Holter, respectively), and type 1 Brugada ECG was most frequently observed between 6 pm and 12 pm. Neither the presence nor the duration of the appearance of type 1 Brugada ECG differed significantly between symptomatic and asymptomatic individuals.
Conclusion : Multichannel Holter ECG recording in the third intercostal space is more sensitive and useful for the diagnosis of type 1 Brugada ECG than repeated 12-lead ECGs or multichannel Holter ECG in the standard position.     

Long-term follow-up in patients with Brugada Syndrome in South China

ObjectiveTo evaluate the presence of Brugada electrocardiogram (ECG) pattern, clinical characteristics, treatment, and long‐term prognosis of Brugada syndrome in southern Chinese population.MethodsThis prospective study consisted of a consecutive series of patients with diagnostic coved type I Brugada ECG pattern at baseline between January 2007 and February 2020. Histories of symptoms including ventricular tachycardia (VT)/ventricular fibrillation (VF) episode, syncope, and family history of Brugada Syndrome (BrS) or unexplained sudden cardiac death were collected. Electrophysiological study and implantable cardioverter‐defibrillator (ICD) were performed. All patients included in this study were followed up in the outpatient department every 6 months after baseline evaluation. Occurrences of syncope, VF, and sudden death were independently analyzed by two cardiologists.Results45 (56.3%) patients were diagnosed with BrS. During a mean follow‐up of 7.9 ± 3.6 years, six patients had experienced documented VF/sudden cardiac death (SCD) or recurrent syncope. Two patients experienced episodes of syncope more than once. Two patients experienced onset of electrical storm with a total of 11 episodes of VF. There were 50% of these events occurring in fever status. One of patient with BrS died of SCD.ConclusionThere was a very low prevalence of Brugada syndrome in southern Chinese population. The risk of arrhythmic events was low in asymptomatic patients. ICD was high effective in preventing SCD without adverse device outcome in long‐term follow‐up. Fever can lead to predispose to malignant arrhythmia, and aggressive treatment of febrile state in Brugada syndrome was recommended.     

The usefulness of the consensus clinical diagnostic criteria in Brugada syndrome

Background

Consensus statements were proposed for the diagnosis of Brugada syndrome (BS). The clinical diagnostic criteria were defined as documented ventricular fibrillation or ventricular tachycardia (VT), family history of sudden cardiac death at < 45 years, diagnostic ECGs of family members, inducibility of VT during electrophysiological study, syncope or nocturnal agonal respiration. The clinical validation of these criteria is still missing.Methods and results280 patients (41 ± 18 years, male: 168 pts) with diagnostic coved type I ECG were included. Consensus clinical diagnostic criteria were present in 244 (87%) patients (40 ± 18 y, 142 males). In 36 pts (13% of the 280 pts, 51 ± 12 years, 27 males) consensus clinical diagnostic criteria were not met. Nine patients (25%) presented with spontaneous type I ECG. Ten of the 36 patients (28%) had a history of atrial fibrillation and 13 (36%) had conduction disease on the baseline ECG. In 23 patients (64%) family screening was not performed. Two of the 36 patients had undocumented syncope during follow-up. Univariate analysis showed no significant difference in event free survival between patients with or without consensus clinical diagnostic criteria.

Conclusions

In a significant number of patients with diagnostic ECG pattern the current diagnostic criteria for BS are not met. These patients have frequently spontaneous type I ECG and clinical signs of Brugada syndrome as paroxysmal atrial fibrillation or conduction disturbances. Our results suggest that in patients with a diagnostic type I ECG pattern the current clinical consensus diagnostic criteria have limited added diagnostic value.     

发热诱发Brugada波的遗传学及心电参数危险因素分析

目的对发热诱发Brugada波的遗传学及心电参数危险性进行分析。方法使用DNA直接测序法对临床收集的5例发热诱发Brugada波患者进行基因筛查,并回顾性调查127例住院发热患者心电图上Brugada波和不完全右束支传导阻滞(IRBBB),并与正常对照组进行心电参数的比较。结果5例发热诱发Brugada ECG患者未发现基因突变。127例发热患者Brugada波1例,发生率为0.8%,13例有IRBBB。发热组患者QTc和TpTe间期较正常对照延长(P<0.05)。0.5~3年随访126例患者无一例发生心源性猝死。结论发热致Brugada波个体与钠通道基因突变无关联。发热诱发Brugada波的健康个体心血管事件发生率低。     

Methods for Improving the Diagnosis of a Brugada ECG Pattern

Brugada syndrome (BrS) is an inherited channelopathy that predisposes individuals to malignant arrhythmias and can lead to sudden cardiac death. The condition is characterized by two electrocardiography (ECG) patterns: the type‐1 or “coved” ECG and the type‐2 or “saddleback” ECG. Although the type‐1 Brugada ECG pattern is diagnostic for the condition, the type‐2 Brugada ECG pattern requires differential diagnosis from conditions that produce a similar morphology. In this article, we present a case that is suspicious but not diagnostic for BrS and discuss the application of ECG methodologies for increasing or decreasing suspicion for a diagnosis of BrS.