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Dependencia de la longitud del ciclo de los efectos electrofisiológicos del aumento de la carga en el miocardio
S M Horner1, D J Dick, C F Murphy
1British Heart Foundation Cardiac Arrhythmia Research Group, Department of Physiology, Charing Cross and Westminster Medical School, London, UK.
Circulation
|September 1, 1996
Resumen
La retroalimentación mecanoeléctrica altera la electrofisiología del corazón bajo cargas cambiantes. Estos cambios en la duración del potencial de acción y las propiedades de restitución eléctrica pueden promover arritmias.
Área de la Ciencia:
- Fisiología cardiovascular fisiología cardiovascular.
- Electrofisiología Cardíaca Electrofisiología cardíaca.
Sus antecedentes:
- La retroalimentación mecanoeléctrica vincula la actividad mecánica con la electrofisiología miocárdica.
- Este proceso está implicado en el desarrollo de arritmias cardíacas.
Objetivo del estudio:
- Investigar los mecanismos aritmogénicos mediante el examen de los cambios en la duración del potencial de acción y la restitución eléctrica.
- Para evaluar el impacto de los cambios de carga transitorios en estos parámetros electrofisiológicos.
Principales métodos:
- Se realizaron experimentos en cerdos anestesiados con oclusión aórtica transitoria para alterar la carga cardíaca.
- Las mediciones incluyeron presión ventricular, potencial de acción monofásico y movimiento de segmento.
- Las curvas de restitución eléctrica se generaron en condiciones de carga normales y alteradas.
Principales resultados:
- El acortamiento de la duración del potencial de acción durante la oclusión disminuyó con intervalos más cortos de latido a latido.
- El aumento de la carga redujo la duración del potencial de acción de la meseta, pero aumentó la duración del potencial de acción temprana.
- El aumento de la carga aumentó la pendiente máxima y extendió el período supernormal de las curvas de restitución eléctrica.
Conclusiones:
- La retroalimentación mecanoeléctrica induce cambios electrofisiológicos dependientes de la velocidad.
- Estas alteraciones en la electrofisiología pueden crear condiciones favorables para la arritmogénesis.
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