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Duración del potencial de acción ventricular humana durante ciclos cortos y largos. Rápida modulación por isquemia
P Taggart1, P M Sutton, M R Boyett
1Department of Cardiology, Middlesex Hospital, London, UK.
Circulation
|November 15, 1996
Resumen
La isquemia aplana la curva de restitución eléctrica en el endocardio humano, lo que podría explicar cómo los latidos prematuros o las pausas desencadenan arritmias ventriculares. Este estudio investigó la restitución eléctrica durante la oclusión de la arteria coronaria.
Área de la Ciencia:
- Cardiología Cardiología.
- Electrofisiología y electrofisiología.
- Investigación de la arritmia cardíaca Investigación de la arritmia cardíaca.
Sus antecedentes:
- Los mecanismos de las arritmias ventriculares durante la isquemia no se comprenden completamente.
- La restitución eléctrica, la relación entre la duración del potencial de acción y la duración del ciclo cardíaco, puede desempeñar un papel.
Objetivo del estudio:
- Para investigar el efecto de la isquemia en la restitución eléctrica en el ventrículo humano.
- Explorar el vínculo entre los cambios en la restitución eléctrica y la arritmogénesis durante la isquemia.
Principales métodos:
- Potenciales de acción monofásicos registrados (MAP) del tabique ventricular derecho en pacientes sometidos a oclusión de la arteria coronaria (LAD o RCA).
- Se utilizaron secuencias de pulsos de prueba para evaluar los cambios en la duración del potencial de acción (APD) con longitudes de ciclo alteradas.
- Compararon los MAP durante la oclusión (isquemia) de la arteria coronaria descendente anterior izquierda (LAD) con la oclusión (control) de la arteria coronaria derecha (RCA).
Principales resultados:
- La oclusión de la LAD acortó significativamente la APD del latido básico (260 a 236 ms) y aplanó la pendiente de restitución de la APD / intervalo diastólico.
- La oclusión de RCA (control) no alteró significativamente la APD de la batida básica o la pendiente de restitución.
- La isquemia inducida por la oclusión de la LAD minimizó, abolió o invirtió la relación normal APD / intervalo diastólico.
Conclusiones:
- La isquemia miocárdica aplana la curva de restitución eléctrica en el endocardio humano.
- La restitución eléctrica alterada durante la isquemia puede contribuir al inicio de las arritmias ventriculares.
- Los hallazgos sugieren un mecanismo para la proarritmia inducida por isquemia.
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