[Congenital atrioventricular block and Wolff-Parkinson-White Syndrome]

We report the case of a patient followed since childhood for congenital complete atrioventricular block. At 28 years of age, atrioventricular conduction through an accessory pathway with long conduction times was detected. Periods of atrioventricular conduction alternated with periods of atrioventricular block. Sinus tachycardia and 1:1 exclusive conduction through the accessory pathway developed with increased sympathic activity (exercise, isoproterenol infusion). We discuss the special features of this case.