Cohort of Patients Referred for Brugada Syndrome Investigation in an Electrophysiology Service - 19-Year Registry / Coorte de Pacientes Encaminhados para Investigação de Síndrome de Brugada em um Serviço Terciário de Eletrofisiologia - Registro de 19 Anos

Abstract Background: Brugada syndrome (SBr) is an arrhythmic condition characterized by ST-T segment abnormalities in the right precordial leads associated with a high risk of ventricular arrhythmias and sudden death. Local data regarding the clinical characteristics of patients with a typical electrocardiographic (ECG) pattern undergoing electrophysiological study are scarce. Objective: To evaluate patients with an ECG pattern suggestive of SBr referred for electrophysiological evaluation in a specialized center. Methods: Cohort study of patients referred for electrophysiological study because of an ECG pattern compatible with SBr between January 1998 and March 2017. Results: Of the 5506 procedures, 35 (0.64%) were for SBr investigation, 25 of which (71.42%) were performed in men. The mean age was 43.89 ± 13.1 years. The ECG patterns were as follows: type I, 22 (62.85%); type II, 12 (34.30%); and type III, 1 (2.85%). Twenty-three patients (65.7%) were asymptomatic, 6 (17.14%) had palpitations, 5 (14.3%) had syncope, and 3 (8.6%) had a family history of sudden death. Electrophysiological study induced ventricular tachyarrhythmias in 16 cases (45.7%), the mean ventricular refractory period being 228 ± 36 ms. Ajmaline / procainamide was used in 11 cases (31.4%), changing the ECG pattern to type I in 7 (63.6%). Sixteen cases (45.7%) received an implantable cardioverter defibrillator (ICD). In a mean 5-year follow-up, 1 of the 16 patients (6.25%) with ICD had appropriate therapy for ventricular fibrillation. There was no death. Other arrhythmias occurred in 4 (11.4%) cases. Conclusions: Most patients are men, and a type I ECG pattern is the main indication for electrophysiological study. Class IA drugs have a high ECG conversion rate. The ICD event rate was 6%. (Arq Bras Cardiol. 2018; [online].ahead print, PP.0-0)

Resumo Fundamento: Síndrome de Brugada (SBr) é uma condição arrítmica definida por anormalidades do segmento ST-T em derivações V1-V3 associada a risco elevado de arritmias ventriculares e morte súbita. Dados locais quanto às características clínicas dos pacientes com padrão eletrocardiográfico (ECG) típico avaliados por estudo eletrofisiológico (EEF) são escassos. Objetivo: Avaliar pacientes com padrão ECG sugestivo de SBr encaminhados para EEF em um centro especializado. Métodos: Estudo de coorte de casos encaminhados para EEF por padrão ECG compatível com SBr, entre janeiro de 1998 e março de 2017. Resultados: Dos 5506 procedimentos, 35 (0,64%) foram para investigação de SBr. Vinte e cinco (71,42%) eram homens. Idade média 43,89 ± 13,1 anos. Apresentação ECG foi tipo I em 22 casos (62,85%), tipo II em 12 (34,30%) e tipo III em 1 (2,85%). Vinte e três (65,7%) eram assintomáticos, 6 (17,14%) apresentavam palpitações, 5 (14,3%) síncope, 3 (8,6%) história familiar de morte súbita. Estudo eletrofisiológico induziu taquiarritmias ventriculares em 16 casos (45,7%), sendo o período refratário ventricular médio de 228 ± 36 ms. Utilizou-se ajmalina/procainamida em 11 casos (31,4%), sendo o padrão ECG transformado em tipo I em 7 (63,6%). Dezesseis casos (45,7%) receberam cardiodes fibrilador (CDI). Em seguimento médio de 5 anos, 1 dos 16 pacientes (6,25%) com CDI teve terapia apropriada para fibrilação ventricular. Nenhuma morte foi registrada. Outras arritmias ocorreram em 4 (11,4%) casos. Conclusões: Homens são maioria, sendo o padrão ECG tipo I a principal indicação de EEF. Droga classe IA possui alta taxa de conversão do padrão ECG. A taxa de eventos no CDI foi de 6%. (Arq Bras Cardiol. 2018; [online].ahead print, PP.0-0)

Brugada Syndrome: A Major Cause of Sudden Cardiac Death.

In 1992 a new syndrome was described consisting of syncopal episodes or sudden death in patients with a structurally normal heart and an electrocardiogram characteristic of right bundle branch block with ST segment elevation in leads V1 to V3. Brugada syndrome is an autosomal dominant disorder. It has been shown to be associated with mutations in the gene (SCN5A) that encodes for the sodium ion channel in cardiac myocyte. Over 160 mutations of gene SCN5A have been identifi ed. Th e incidence of the disease is diffi cult to estimate, but it causes sudden deaths of 5 per 10,000 inhabitants per year and involved much more frequently in people of Asian ancestry. Diagnosis can be easily made by means of genetic analysis and ECG. Recent data suggest that loss of the action potential dome in the right ventricular epicardium underlies ST segment elevation seen in this syndrome. Right ventricular epicardium is preferentially aff ected because of the predominance of transient outward current in this tissue. Antiarrhythmic drugs like amiodarone and beta-blockers do not prevent death in symptomatic or asymptomatic individuals. Th ough Implantation of an automatic cardioverter–defi brillator is the only recently proven eff ective therapy; Quinidine has been found to decrease Ventricular fi brillation and could prove to be a secured option of implantable cardioverter–defi brillator. However, researcher set focus on gene therapy that may off er an enduring cure in future years. Th e purpose of this brief review is to record the past highlights that have brought us to our present understanding of Brugada syndrome.