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La retroalimentación mecanoeléctrica como un nuevo mecanismo de remodelación eléctrica cardíaca
Darwin Jeyaraj1, Lance D Wilson, Jia Zhong
1Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, 2500 MetroHealth Dr, Cleveland, OH 44109-1998, USA.
Circulation
|June 15, 2007
Resumen
La remodelación eléctrica ventricular (VER) se desencadena por una tensión mecánica, no por cambios estructurales. Este estudio revela que la tensión localizada del músculo cardíaco amplifica las diferencias eléctricas, lo que lleva a la memoria de onda T y VER.
Área de la Ciencia:
- Cardiología Cardiología.
- Electrofisiología Cardíaca Electrofisiología cardíaca.
- La biofísica es la biofísica.
Sus antecedentes:
- La activación alterada del corazón causa remodelación eléctrica ventricular (VER), lo que lleva a la memoria de onda T y cambios mecánicos.
- Los mecanismos que inician la remodelación del canal iónico cardíaco en VER no se comprenden completamente.
- La memoria de onda T está vinculada a la expresión alterada del canal iónico sarcolemal.
Objetivo del estudio:
- Investigar si la retroalimentación mecanoeléctrica inducida por el esfuerzo mecánico desencadena VER.
- Para aclarar los mecanismos biofísicos que subyacen a VER.
Principales métodos:
- La estimulación ventricular se utilizó para inducir VER en perros (n = 6) durante 4 semanas.
- Imágenes de potenciales de acción óptica transmural de múltiples segmentos evaluaron la actividad eléctrica.
- La resonancia magnética marcada in vivo midió la tensión miocárdica.
Principales resultados:
- El pacing indujo una prolongación significativa de la duración del potencial de acción en segmentos miocárdicos de activación tardía.
- Se observó un aumento de 2 veces en la tensión circunferencial en segmentos sometidos a VER.
- VER se produjo sin evidencia de hipertrofia celular, descartando la remodelación estructural.
Conclusiones:
- La tensión circunferencial mejorada localmente desencadena la remodelación de la función del canal iónico en VER.
- Un nuevo mecanismo de retroalimentación mecanoeléctrica contribuye a las heterogeneidades eléctricas en el corazón.
- Estos hallazgos ofrecen información sobre la remodelación eléctrica fisiológica y potencialmente perjudicial.
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