The Brugada syndrome is a genetic disease that is manifest by abnormal electrocardiogram (ECG) findings and an increased risk of sudden cardiac death. It is also known as Sudden Unexpected Death Syndrome¹ (SUDS), and is the most common cause of death in the young in Thailand and Laos².

First described in 1992³, the Brugada syndrome causes sudden death by causing ventricular fibrillation (a lethal arrhythmia) in the heart.

Genetics and pathophysiology

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Brugada syndrome is due to a mutation in the gene that encodes for the sodium ion channel in the cell membranes of the muscle cells of the heart (the myocytes). The gene, named SCN5A, is located on the short arm of the third chromosome (3p21). Gain-of-function mutations in this gene lead to elongation of the cardiac action potential. It is suspected that this occurs because the sodium channel isn't able to bind properly to ankyrin-G, an important protein mediating interaction between ion channels and cytoskeletal elements. This condition is inherited in an autosomal dominant pattern.

Electrocardiography

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In some cases, the disease can be detected by observing characteristic patterns on an electrocardiogram, which may be present all the time, or might be elicited by the administration of particular drugs. The pattern seen on the ECG is persistent ST elevations in the electrocardiographic leadsV₁-V₃ with a right bundle branch block (RBBB) appearance with or without the terminal S waves in the lateral leads that are associated with a typical RBBB. A prolongation of the PR interval (a conduction disturbance in the heart) is also frequently seen.

Treatment

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The cause of death in Brugada syndrome is ventricular fibrillation. While there is no treatment modality that prevents ventricular fibrillation from occurring in this syndrome, treatment lies in termination of this lethal arrhythmia before it causes death. This is done via implantation of an implantable cardioverter-defibrillator (ICD), which continuously monitors the heart rhythm and will defibrillate an individual if ventricular fibrillation is noted. Those with risk factors for coronary artery disease may require an angiogram before ICD implantation.

See also

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• Cardiac action potential
• Genetics
• Ion channel
• Tambocor

References

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1. Hong K, Berruezo-Sanchez A, Poungvarin N, Oliva A, Vatta M, Brugada J, Brugada P, Towbin JA, Dumaine R, Pinero-Galvez C, Antzelevitch C, Brugada R. Phenotypic characterization of a large European family with Brugada syndrome displaying a sudden unexpected death syndrome mutation in SCN5A. J Cardiovasc Electrophysiol. 2004 Jan;15(1):64-9. PMID 15028074
2. Brugada J, Brugada P, Brugada R. The syndrome of right bundle branch block ST segment elevation in V1 to V3 and sudden death--the Brugada syndrome. Europace. 1999 Jul;1(3):156-66. PMID 11225790
3. Brugada P, Brugada J. Right bundle branch block, persistent ST segment elevation and sudden cardiac death: a distinct clinical and electrocardiographic syndrome. A multicenter report. J Am Coll Cardiol. 1992 Nov 15;20(6):1391-6. PMID 1309182

External links

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• Graham-Rowe: "Death in the Family", New Scientist 20 Sept. 2002
• Algado et al: http://www.medspain.com/ant/n13_jun00/Brugada.htm
• Behr: http://www.c-r-y.org.uk/long_qt_syndrome.htm
• The Ramon Brugada Senior Foundation

Cardiac electrophysiology | Channelopathy | Eponymous diseases | Genetic disorders

Syndrome de Brugada | Brugada-Syndrom | Síndrome de Brugada | ブルガダ症候群