Fenómeno de fatiga, en una vía accesoria manifiesta, luego de la aplicación de radiofrecuencia

Rate and time-dependent impairment in conduction (Fatigue phenomenon) is a characteristic of the AV node. It has also been demonstrated in the His Purkinje system and accessory A-V pathway with depressed conduction or under the effect of sodium channel blockers. The present case demonstrates for the first time, the occurrence of fatigue phenomenon in an accessory A-V pathway following the application of radiofrequency energy. The transient injury resulted in anterograde block that was exacerbated with prolonged periods of stimulation and at fast rates. Hypopolarization of the accessory A-V pathway due to radiofrenquency energy with inactivation of the sodium channels appears as the most likely explanation of this phenomenon.