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La oxigenación del miocardio durante los estados de alto trabajo en los corazones con remodelación postinfarto
1Departments of Medicine, Biochemistry, and Radiology and the Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA.
Circulation
|February 23, 1999
Resumen
La remodelación ventricular izquierda postinfarto (LVR) conduce a una reducción de fosfatos de alta energía (HEP). Este estudio encontró que los bajos niveles de HEP en la insuficiencia cardíaca no se deben a la insuficiente disponibilidad de oxígeno, incluso durante el aumento de la carga de trabajo del corazón.
Área de la Ciencia:
- Cardiología Cardiología.
- Fisiología cardiovascular fisiología cardiovascular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La remodelación ventricular izquierda postinfarto (LVR) está relacionada con la disminución de los niveles de fosfato de alta energía (HEP) del miocardio.
- Estas reducciones de HEP son más severas en animales que desarrollan insuficiencia cardíaca congestiva (ICC).
- El aumento de la carga de trabajo cardíaca exacerba la pérdida de HEP, lo que sugiere isquemia inducida por la demanda.
Objetivo del estudio:
- Para probar la hipótesis de que la inadecuada disponibilidad de oxígeno en los miocitos subyace a las anomalías de HEP en la LVR y CHF postinfarto.
- Investigar la relación entre el suministro de oxígeno del miocardio y los niveles de HEP en condiciones basales y estimuladas.
Principales métodos:
- Infarto de miocardio inducido a través de la ligadura de la arteria coronaria en cerdos.
- Los grupos incluían animales normales, LVR compensado y CHF.
- La fosfocreatina/ATP (PCr/ATP) medida por RMN 31P; la desoximioglobina (Mb-delta) medida por RMN 1H en el miocardio remoto.
Principales resultados:
- El PCr/ATP basal se redujo en los corazones postinfarto, significativamente en la insuficiencia cardíaca congestiva.
- La dobutamina aumentó la tasa de producto de presión en los corazones normales y LVR, causando disminuciones comparables de PCr / ATP sin Mb-delta detectable.
- En la insuficiencia cardíaca congestiva, la respuesta a la dobutamina se atenuó y no se asoció con Mb-delta.
Conclusiones:
- La disminución de PCr/ATP inducida por la dobutamina no se debe a una insuficiente disponibilidad de oxígeno.
- La baja PCr/ATP basal y la respuesta atenuada a la dobutamina en la insuficiencia cardíaca congestiva se produjeron sin hipoxia miocárdica.
- La EPH y las anomalías contráctiles en la insuficiencia cardíaca congestiva no son causadas por una insuficiente disponibilidad de oxígeno.
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