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[Brugada syndrome]
Kiyotaka Matsuo1, Katsusuke Yano
1Third Department of Internal Medicine, Nagasaki University School of Medicine.
Insights
Brugada syndrome, a heart condition causing sudden death, is linked to genetic mutations affecting cardiac sodium channels. Early detection and treatment, like implantable defibrillators, are crucial for preventing fatal arrhythmias.
Area of Science:
- Cardiology
- Genetics
- Electrophysiology
Context:
- Brugada syndrome presents with a distinct ECG pattern: right bundle branch block and ST-segment elevation in right precordial leads.
- This condition is associated with an increased risk of sudden cardiac death due to ventricular fibrillation (VF).
Purpose:
- To elucidate the genetic basis and electrophysiological mechanisms underlying Brugada syndrome.
- To highlight diagnostic features and therapeutic strategies for managing patients at risk of sudden death.
Summary:
- Brugada syndrome is characterized by specific ECG abnormalities and is primarily caused by mutations in the SCN5A gene, which encodes the cardiac sodium channel.
- The underlying cellular mechanism involves an outward shift in ionic current during phase 1 of the right ventricular epicardial action potential.
- The characteristic ECG pattern can be intermittent, exacerbated before VF episodes, and unmasked by certain antiarrhythmic drugs. Increased vagal activity, particularly during sleep, is linked to VF development.
Impact:
- Identifies SCN5A gene mutations as a primary cause, advancing our understanding of Brugada syndrome's genetic etiology.
- Emphasizes the role of electrophysiological abnormalities in arrhythmogenesis, guiding diagnostic and therapeutic approaches.
- Highlights implantable cardioverter-defibrillators (ICDs) as the effective therapy for preventing sudden death in high-risk individuals.
Abstract:
Brugada syndrome is characterized by an ECG pattern of right bundle branch block and ST-segment elevation in right precordial leads, and sudden death caused by ventricular fibrillation(VF). The cellular basis for the syndrome is thought to be due to an outward shift in the ionic current active during phase 1 of the right ventricular epicardial action potential. Mutations of the cardiac sodium channel gene, SCN5A, have been identified as the genesis of the syndrome. This ECG pattern, which appears intermittently in most patients, is accentuated just before and after episodes of VF and is unmasked by class IA and IC antiarrhythmic agents. Development of VF is associated with an increase in vagal activity, and it occurs frequently during sleep. Implantable-cardioverter defibrillator is the effective therapy for prevention from sudden death.