Clinical Studies
The Brugada syndrome: clinical, electrophysiologic and genetic aspects

https://doi.org/10.1016/S0735-1097(98)00528-2Get rights and content
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Abstract

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.

Abbreviations

ARVD
arrhythmogenic right ventricular dysplasia
ECG
electrocardiographic
ERS
early repolarization syndrome
ICa
calcium current
ICD
implantable cardiac defibrillator
IK-ATP
adenosine triphosphate–sensitive potassium current
INa
sodium current
Ito
transient outward current
RBBB
right bundle branch block
SUDS
sudden and unexplained death syndrome
TdP
Torsade de Pointes
VF
ventricular fibrillation
VT
ventricular tachycardia

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Supported by grants from the National Institutes of Health (HL47678) and American Heart Association, New York State Affiliate and by the Masons of New York State and Florida.