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La inestabilidad y la triangulación del potencial de acción predicen una proarritmia grave, pero la prolongación de
L M Hondeghem1, L Carlsson, G Duker
1Department of Pharmacology, Leuven, Belgium. luchondeghem@yahoo.com
Circulation
|April 18, 2001
Resumen
La prolongación de la duración del potencial de acción (APD) puede ser antiarrítmica o proarrítmica. La inestabilidad y la triangulación de la APD determinan si el alargamiento es seguro o si induce arritmias peligrosas como torsade de pointes.
Área de la Ciencia:
- Electrofisiología cardíaca electrofisiología cardíaca.
- Farmacología Farmacología.
- Investigaciones cardiovasculares en la investigación cardiovascular.
Sus antecedentes:
- La prolongación de la duración del potencial de acción (APD) es un mecanismo antiarrítmico conocido (clase 2I).
- Paradójicamente, la prolongación de la DPA también puede inducir proarritmia, específicamente torsade de pointes.
- Comprender los determinantes de estos efectos opuestos es crucial para el desarrollo de fármacos y la seguridad del paciente.
Objetivo del estudio:
- Para investigar los efectos electrofisiológicos cardíacos de 702 sustancias químicas.
- Identificar los factores clave que determinan si la prolongación de la DPA es antiarrítmica o proarrítmica.
- Para correlacionar los hallazgos in vitro con el potencial proarrítmico in vivo.
Principales métodos:
- Utilizó un modelo de corazón de conejo con perfusión de Langendorff para evaluar 702 sustancias químicas.
- La inestabilidad temporal medida de la APD, la triangulación, la dependencia de uso inverso y la inducción del latido ectópico.
- Resultados proarrítmicos evaluados, incluyendo taquicardia ventricular polimórfica y monomórfica, y torsade de pointes.
Principales resultados:
- La inestabilidad temporal, la triangulación y la dependencia inversa del uso se identificaron como determinantes críticos de la proarritmia.
- La prolongación de la DPA (>50 ms) indujo proarritmia sólo cuando la inestabilidad y la triangulación estaban presentes.
- En ausencia de inestabilidad y triangulación, la prolongación de la DPA demostró efectos antiarrítmicos significativos.
- El acortamiento de la APD con inestabilidad y triangulación fue marcadamente proarrítmico.
- La inestabilidad in vitro y la triangulación predijeron fuertemente la proarritmia in vivo (torsade de pointes).
Conclusiones:
- El alargamiento de la APD sin inestabilidad o triangulación es antiarrítmico.
- La inestabilidad y la triangulación de la APD son predictores clave de la proarritmia, que anulan los efectos de la prolongación de la APD.
- Estos hallazgos tienen implicaciones significativas para la evaluación de la seguridad de los medicamentos cardíacos.
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