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Labilidad de repolarización temporal en cardiomiopatía hipertrófica causada por mutaciones genéticas de cadena pesada
W L Atiga1, L Fananapazir, D McAreavey
1Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
Circulation
|March 22, 2000
Resumen
Los pacientes con cardiomiopatía hipertrófica (HCM) causada por mutaciones genéticas de cadena pesada de beta-miosina (beta-MHC) muestran una repolarización anormal del corazón. Esta repolarización labile, identificada por el análisis de la variabilidad QT, puede aumentar su riesgo de muerte súbita cardíaca.
Área de la Ciencia:
- Cardiología Cardiología.
- Genética La genética.
- Electrofisiología y electrofisiología.
Sus antecedentes:
- La cardiomiopatía hipertrófica (HCM) vinculada a mutaciones genéticas aumenta el riesgo de muerte súbita.
- El análisis de la variabilidad QT es una herramienta para identificar pacientes de alto riesgo con arritmias ventriculares.
- Las mutaciones genéticas de cadena pesada de beta-miosina (beta-MHC) son una causa conocida de HCM.
Objetivo del estudio:
- Para investigar si los pacientes con HCM con mutaciones en el gen beta-MHC exhiben repolarización ventricular lábil.
- Para evaluar la utilidad del análisis de la variabilidad de QT beat-to-beat en estos pacientes.
- Para correlacionar las anomalías de la variabilidad QT con mutaciones específicas del beta-MHC.
Principales métodos:
- Se midió el índice de variabilidad QT y la coherencia entre la frecuencia cardíaca y el intervalo QT utilizando monitores Holter.
- Se estudiaron 36 pacientes con HCM debido a mutaciones beta-MHC.
- 26 individuos sanos de edad y sexo coincidentes sirvieron como controles.
Principales resultados:
- Los pacientes con CMH exhibieron un índice de variabilidad QT significativamente más alto en comparación con los controles.
- Los pacientes con la mutación Arg(403)Gln beta-MHC mostraron las anomalías de variabilidad QT más pronunciadas.
- Se observó coherencia entre la frecuencia cardíaca más baja y el intervalo QT en pacientes con CMH, particularmente en aquellos con la mutación Arg{403}Gln.
Conclusiones:
- Los pacientes con HCM con mutaciones en el gen beta-MHC muestran repolarización lábil, lo que sugiere un mayor riesgo de muerte súbita.
- El análisis de la variabilidad QT puede cuantificar las anomalías de repolarización en HCM.
- Las mutaciones específicas del beta-MHC, como el Arg{403}Gln, se asocian con una variabilidad QT más severa, lo que indica un pronóstico más pobre.
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