Oxidative stress on pulmonary vein and left atrium arrhythmogenesis.
Circ J
; 74(8): 1547-56, 2010 Aug.
Article
em En
| MEDLINE
| ID: mdl-20562495
ABSTRACT
BACKGROUND:
Oxidative stress and pulmonary veins (PVs) play critical roles in the pathophysiology of atrial fibrillation. The purpose of the present study was to investigate whether oxidative stress and antioxidant agents can change the electrophysiological characteristics of the left atrium (LA) and PVs. METHODS ANDRESULTS:
Conventional microelectrodes were used to record the action potentials (APs) in isolated rabbit PV and LA specimens before and after H(2)O(2) administration with or without ascorbic acid or N-mercaptopropionyl-glycine (N-MPG, a free radical .OH scavenger). H(2)O(2) (0.02 and 0.2 mmol/L) decreased the PV spontaneous rates from 2.0+/-0.1 Hz to 1.6+/-0.1 Hz, and 1.7+/-0.1 Hz (n=10, P<0.05), but H(2)O(2) (2 mmol/L) increased PV spontaneous rates from 2.0+/-0.1 Hz to 2.8+/-0.2 Hz. H(2)O(2) easily induced PV burst firing and early afterdepolarizations, but not in the LA. H(2)O(2) shortened the AP duration and increased the contractile force to a greater extent in the LA than in PVs. In addition, the H(2)O(2)-induced PV burst firing and increasing spontaneous rates were suppressed or attenuated by pretreatment with ascorbic acid (1 mmol/L) or N-MPG (10 mmol/L).CONCLUSIONS:
H(2)O(2) significantly changed the electrophysiological characteristics of PV and LA through activation of free radicals and may facilitate the occurrence of atrial fibrillation.
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Base de dados:
MEDLINE
Assunto principal:
Veias Pulmonares
/
Fibrilação Atrial
/
Estresse Oxidativo
/
Técnicas Eletrofisiológicas Cardíacas
/
Átrios do Coração
Limite:
Animals
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article