Enhanced Na(+) channel intermediate inactivation in Brugada syndrome.
Circ Res
; 87(8): E37-43, 2000 Oct 13.
Article
em En
| MEDLINE
| ID: mdl-11029409
ABSTRACT
Brugada syndrome is an inherited cardiac disease that causes sudden death related to idiopathic ventricular fibrillation in a structurally normal heart. The disease is characterized by ST-segment elevation in the right precordial ECG leads and is frequently accompanied by an apparent right bundle-branch block. The biophysical properties of the SCN5A mutation T1620M associated with Brugada syndrome were examined for defects in intermediate inactivation (I(M)), a gating process in Na(+) channels with kinetic features intermediate between fast and slow inactivation. Cultured mammalian cells expressing T1620M Na(+) channels in the presence of the human beta(1) subunit exhibit enhanced intermediate inactivation at both 22 degrees C and 32 degrees C compared with wild-type recombinant human heart Na(+) channels (WT-hH1). Our findings support the hypothesis that Brugada syndrome is caused, in part, by functionally reduced Na(+) current in the myocardium due to an increased proportion of Na(+) channels that enter the I(M) state. This phenomenon may contribute significantly to arrhythmogenesis in patients with Brugada syndrome. The full text of this article is available at http//www.circresaha.org.
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Base de dados:
MEDLINE
Assunto principal:
Arritmias Cardíacas
/
Fibrilação Ventricular
/
Síndrome do QT Longo
/
Canais de Sódio
/
Morte Súbita Cardíaca
Tipo de estudo:
Etiology_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article