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Circuitos reentrantes en el nodo atrioventricular canino durante los ecos auriculares y ventriculares: correlación
Peter Loh1, Siew Yen Ho, Tokuhiro Kawara
1Experimental and Molecular Cardiology Group, Academic Medical Center, Amsterdam, The Netherlands. p.loh@hli.azu.nl
Circulation
|July 2, 2003
Resumen
El estudio revela que las distintas regiones nódales AV en los perros permiten la fisiología dual y la reentrada. El bloqueo de conducción y la conducción lenta ocurren en las uniones de tejidos, facilitando los ecos auriculares y ventriculares.
Área de la Ciencia:
- Electrofisiología cardiovascular electrofisiología cardiovascular.
- La anatomía cardíaca anatomía cardíaca.
- La arritmogénesis es la arritmogénesis.
Sus antecedentes:
- La base anatómica precisa de la reentrada nodal atrioventricular (AV) aún no se entiende por completo.
- La localización de los circuitos reentrantes y la identificación de los sitios de conducción lenta y bloqueo son cruciales para comprender la función nodal AV.
Objetivo del estudio:
- Para correlacionar la histología nodal AV con hallazgos electrofisiológicos en corazones de perros aislados.
- Para localizar los circuitos reentrantes responsables de los ecos auriculares y ventriculares.
- Para caracterizar los sitios de conducción lenta y bloqueo de conducción dentro del nodo AV.
Principales métodos:
- La actividad eléctrica extracelular se registró a alta resolución (distancia entre electrodos de 0,3-0,5 mm) en el triángulo de Koch de 10 corazones de perro aislados después de la extirpación del tejido auricular.
- Cinco corazones se sometieron a un examen histológico para correlacionar las grabaciones eléctricas con la arquitectura del tejido.
- Se indujeron ecos auriculares y ventriculares para estudiar los fenómenos de reentrada.
Principales resultados:
- El bloqueo de conducción unidireccional se produjo en la unión de células de transición auricular en el nodo AV superior durante los ecos auriculares.
- Se identificaron zonas de conducción lenta en las uniones de los nodos atrial-transicional o transicional-compacto en el nodo AV inferior.
- Durante los ecos ventriculares, el bloqueo de conducción se produjo en la unión del nodo compacto-célula de transición en el nodo AV superior, con zonas de conducción lenta en la región inferior.
Conclusiones:
- La arquitectura del tejido y la disociación funcional entre las regiones superior e inferior del nodo AV en perros facilitan la fisiología dual y la reentrada.
- La conducción lenta y el bloqueo de conducción funcional se producen predominantemente en las uniones entre diferentes tipos de tejidos dentro del área nodal AV.
- Los sitios específicos de bloqueo de conducción en las uniones celulares de transición auricular y de transición de nodo compacto explican los mecanismos de los ecos auriculares y ventriculares, respectivamente.
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