From the Guidelines
Brugada syndrome is a genetic disorder characterized by a specific pattern of ST-segment elevation in the right precordial leads on an electrocardiogram (ECG), which can lead to life-threatening ventricular arrhythmias and sudden cardiac death.
Key Features of Brugada Syndrome
- Characterized by coved ST elevation in leads V1 or V2, either spontaneously or induced by sodium channel-blocking drugs, in the absence of other causes of ST elevation 1
- Associated with syncope or sudden cardiac arrest due to ventricular fibrillation, predominantly in young males, although it can occur in all age groups 1
- Diagnosis is based on the presence of a type 1 Brugada ECG pattern, which is defined as a coved ST elevation of ≥2 mm in one or more leads among the right precordial leads V1 and/or V2, positioned in the second, third, or fourth intercostal space 1
- Risk stratification is important, as patients with a spontaneous Brugada pattern have a worse prognosis than those with a drug-induced pattern, and patients with syncope and spontaneous ST-segment elevation have a higher risk of cardiac arrest 1
Management and Treatment
- Implantable cardioverter-defibrillator (ICD) implantation is recommended for patients with a diagnosis of Brugada syndrome who have had a cardiac arrest or have documented spontaneous sustained ventricular tachycardia (VT) 1
- ICD implantation should be considered in patients with a spontaneous diagnostic type I ECG pattern and a history of syncope 1
- Quinidine or isoproterenol may be considered in patients with Brugada syndrome to treat electrical storms, and catheter ablation may be considered in patients with a history of electrical storms or repeated appropriate ICD shocks 1
- Lifestyle changes, such as avoidance of drugs that may induce ST-segment elevation, avoidance of excessive alcohol intake and large meals, and prompt treatment of fever, are recommended for all patients with Brugada syndrome 1
From the Research
Definition and Characteristics of Brugada Syndrome
- Brugada syndrome (BrS) is an inherited cardiac disorder characterized by a typical ECG pattern and an increased risk of arrhythmias and sudden cardiac death (SCD) 2, 3, 4, 5, 6.
- It is a rare hereditary arrhythmia disorder with a distinctive ECG pattern, correlated with an increased risk of ventricular arrhythmias and SCD in young adults 3.
- BrS is a complex entity in terms of mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management 3, 4.
Diagnosis and Risk Stratification
- Diagnosis is based on the presence of a spontaneous or drug-induced coved-type ST segment elevation 4, 5, 6.
- The primary challenge in individuals with a BrS type 1 ECG is to identify those who are at risk for sudden death, and researchers propose the use of a multiparametric clinical and instrumental strategy for risk stratification 3.
- Risk assessment in patients diagnosed with BrS is controversial, especially with regard to the predictive value of programmed electrical stimulation and novel ECG parameters, such as QRS fragmentation 6.
Genetics and Pathophysiology
- BrS is a Mendelian condition inherited in an autosomal dominant manner with incomplete penetrance, despite the recent developments in the field of genetics and the latest hypothesis of additional inheritance pathways proposing a more complex mode of inheritance 3.
- More than 18 genes associated with BrS have been discovered, and recent evidence has suggested a complex polygenic mode of inheritance with multiple common and rare genetic variants acting in concert to produce the BrS phenotype 6.
- The main electrophysiological mechanism of BrS requires further research, with prevailing theories centered on aberrant repolarization, depolarization, and current-load match 3, 4.
Treatment and Management
- Current treatment options include pharmacological therapy to reduce the occurrence of arrhythmic events or to abort these episodes, and interventions such as implantable cardioverter-defibrillator insertion or radiofrequency ablation of abnormal arrhythmic substrate 4, 6.
- The first line of BrS therapy remains an implantable cardioverter defibrillator (ICD), although radiofrequency catheter ablation has been shown to be an effective option in patients with contraindications for an ICD 6.