[Role of the AV node and adrenergic stimulation in initiation of fascicular and atrioventricular nodal tachycardias--a case report].

Fascicular tachycardia is an uncommon form of left ventricular tachycardia in young patients with normal heart. Ventriculo-atrial conduction during VT is usually absent. Retrograde conduction was observed in a 14-year old boy with left posterior fascicular VT (LPF-VT) triggered by exercise. During isoproterenol infusion, atrial stimulation induced a cascade of arrhythmias--echo, pair or runs of AVNRT and fascicular tachycardia triggered by fascicular beats. Also, during infusion LPF-VT was initiated spontaneously. After successful ablation of VT, sustained typical AVNRT was inducible. Finally, ablation of slow pathway of AV node was performed. After ablation,no arrhythmia was inducible following isoproterenol and exercise.