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Divertida desregulación de la corriente y disfunción del nodo sinusal asociada con taquiarritmia auricular: una base
Yung-Hsin Yeh1, Brett Burstein, Xiao Yan Qi
1Department of Medicine, Montreal Heart Institute Research Center and Université de Montréal, Montreal, Quebec, Canada.
Circulation
|March 18, 2009
Resumen
Las taquiarritmias auriculares (TA) perjudican la función del nodo sinoatrial (SAN) al reducir la expresión de los canales iónicos clave, en particular la corriente divertida (I). Esta remodelación del canal iónico contribuye a la disfunción SAN y las arritmias asociadas.
Área de la Ciencia:
- Cardiología Cardiología.
- Electrofisiología y electrofisiología.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La disfunción del nodo sinoatrial (SAN) a menudo está relacionada con las taquiarritmias auriculares (AT).
- La disfunción post-AT SAN puede conducir a síncope y requerir la implantación de marcapasos.
- Los mecanismos subyacentes a la disfunción SAN inducida por AT no se comprenden completamente.
Objetivo del estudio:
- Para investigar si los AT perjudican la función SAN al alterar la expresión del canal iónico.
- Para identificar canales iónicos específicos y subunidades afectadas por ATs.
- Para correlacionar los cambios en la expresión de los canales iónicos con los déficits funcionales en las células SAN.
Principales métodos:
- Se recolectaron tejidos SAN de perros de control y perros sometidos a taquicardia auricular de 7 días.
- Se utilizaron técnicas de pinza de parche de célula completa para medir las corrientes iónicas en células SAN individuales.
- La reacción en cadena de la polimerasa de transcripción inversa en tiempo real (RT-PCR) cuantificó la expresión de ARNm de las subunidades clave de los canales iónicos.
Principales resultados:
- El tachypacing auricular aumentó significativamente el tiempo de recuperación de SAN, lo que indica una función deteriorada.
- La expresión de las subunidades HCN2, HCN4 y minK se redujo significativamente en SAN. con ritmo acelerado.
- Las densidades de la corriente divertida (I(f)) y la corriente lenta de rectificador retardado (I(Ks)) se redujeron, con los cambios de I(f) explicando principalmente la periodicidad SAN más lenta.
- La expresión de otros canales clave (I ((Kr), I ((Ks), I ((CaL), I ((CaT), conexina 43) no se vio afectada.
Conclusiones:
- Las taquiarritmias auriculares regulan a la baja SAN HCN2/4 y la expresión de la subunidad minK.
- Esto conduce a la reducción de las corrientes I(f) e I(Ks), lo que contribuye a la disfunción de las SAN.
- La remodelación inducida por la taquicardia de los canales iónicos SAN, especialmente I(f), es un factor clave en la asociación entre los AT y la disfunción SAN.
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