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El aumento de la variabilidad a corto plazo de la repolarización predice torsades de pointes inducidas por d-sotalol

Morten B Thomsen¹, S Cora Verduyn, Milan Stengl

¹Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands.

|October 13, 2004

Resumen

La variabilidad de la repolarización de latido a latido, específicamente la variabilidad a corto plazo (STV), predice la arritmia de torsadas de puntos (TdP) inducida por medicamentos. La STV es un predictor más confiable que la prolongación del intervalo QT para identificar a los pacientes en riesgo.

Área de la Ciencia:

Cardiología Cardiología.
Electrofisiología y electrofisiología.
Farmacología Farmacología.

Sus antecedentes:

La identificación de pacientes en riesgo de sufrir arritmia torsada de puntos (TdP) inducida por fármacos es un reto.
El aumento de la labilidad de repolarización temporal es un predictor potencial de la proarritmia.
Se ha investigado la variabilidad de repolarización (BVR) de latido a latido como un parámetro predictivo.

Objetivo del estudio:

Para comparar el valor predictivo de diferentes parámetros de repolarización para la TdP inducida por fármacos.
Investigar el papel del BVR, cuantificado como variabilidad a corto plazo (STV), en la predicción de TdP.
Para evaluar la STV en perros con bloqueo atrioventricular crónico y en miocitos ventriculares aislados.

Principales métodos:

Se administra d-sotalol a perros anestesiados con bloqueo atrioventricular crónico.
BVR cuantificado utilizando gráficas de Poincare y STV medido de la duración del potencial de acción monofásico del ventrículo izquierdo.
Se investigó la STV en miocitos ventriculares aislados después del bloqueo I(Kr).

Principales resultados:

La TdP inducida por fármacos en perros no se explicó únicamente por la prolongación del intervalo QT.
La ocurrencia de TdP se asoció con un aumento de la STV del potencial de acción monofásico del ventrículo izquierdo.
La ausencia de TdP a pesar de la prolongación de la QT (c) después de la amiodarona se relacionó con la STV sin cambios.
La STV aumentó después del bloqueo I(Kr) en los miocitos, lo que se correlaciona con las despolarizaciones posteriores tempranas.

Conclusiones:

La proarritmia, específicamente TdP, está relacionada con el BVR (cuantificado como STV) en lugar de las diferencias en la prolongación de la repolarización.
STV del ventrículo izquierdo es un nuevo parámetro potencial para predecir TdP inducida por fármacos en pacientes.

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