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Excitación reentrante alrededor de un obstáculo fijo en el miocardio ventricular anisotrópico uniforme
J Brugada1, L Boersma, C J Kirchhof
1Department of Physiology, University of Limburg, Maastricht, The Netherlands.
Circulation
|September 1, 1991
Resumen
La anisotropía tisular y los latidos prematuros inician la taquicardia ventricular (VT) de reentrada al causar un bloqueo de conducción paralelo a la orientación de la fibra en el tejido miocárdico uniforme. Este hallazgo aclara los mecanismos de iniciación de la VT.
Área de la Ciencia:
- Fisiología cardiovascular fisiología cardiovascular.
- Electrofisiología y electrofisiología.
- Las arritmias cardíacas son arritmias cardíacas.
Sus antecedentes:
- La taquicardia ventricular reentrante (VT) es una arritmia que pone en peligro la vida.
- Comprender el inicio de la formación ventricular es crucial para desarrollar terapias efectivas.
- La anisotropía tisular y la dispersión de la refractividad están implicadas en la patogénesis de la VT.
Objetivo del estudio:
- Investigar el papel de la anisotropía tisular en el inicio de la taquicardia ventricular reentrante (VT).
- Examinar la influencia de la dispersión de la refractividad en el inicio de la VT.
- Para aclarar los mecanismos subyacentes a la reentrada de VT en el miocardio anisotrópico uniforme.
Principales métodos:
- Creado un anillo de epicardio ventricular anisotrópico uniforme utilizando una técnica de congelación endocárdica en corazones de conejo perfundidos con Langendorff.
- Se utilizó un mapeo de alta resolución (248 canales) para analizar los patrones de activación epicárdica.
- Los latidos prematuros inducidos en múltiples puntos para evaluar el inicio de la VT reentrante.
Principales resultados:
- Se inició la VT de reentrada en 43 de los 272 puntos probados.
- La velocidad de conducción fue significativamente mayor paralela (60 cm/seg) versus perpendicular (25 cm/seg) a la orientación de la fibra.
- El bloque de conducción unidireccional se produjo predominantemente en paralelo a la orientación de la fibra (41/43 casos).
- La dispersión de la refractividad jugó un papel menor en la formación de bloques (12/43 casos).
Conclusiones:
- En el miocardio anisotrópico uniforme, la trombosis venosa reentrante es iniciada por latidos prematuros.
- La disminución de la eficacia estimulante de los latidos prematuros conduce a un bloque de conducción preferencial paralelo a la orientación de la fibra.
- Este bloque preferencial es el mecanismo principal para la iniciación de VT reentrantes en este modelo.
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