Fascicular tachycardia (FT) is uncommon form of left ventricular tachycardia in young patients. This tachycardia is usually initiated by programmed ventricular or atrial stimulation. The electrophysiology study and RF ablation were preformed in 5 boys with FT, mean age 14yr 6 months (ranged 11yr 3 month-18yr 6 month). All patients had normal heart morphology. The clinical arrhythmia was triggered by exercise in all patients. The EPS and RF ablation were preformed under general anesthesia in 2 patients and in local in three. In all but one tachycardia was difficult to induced, so Isoproterenol was used. Tachycardia started with right atrium rapid pacing (360 ms) in one, coronary sinus pacing 8 x 460+450ms in one, coronary sinus pacing 8 x 460+360ms in 1 patient. In 2 boys coronary sinus pacing 8 x 460ms+300+300ms (1 pts), and 8 x 460ms+240+210ms (1pts) initiated atrio-ventricular nodal tachycardia which switch to fascicular tachycardia. In 2 boys also RV pacing 460ms+300ms (1 pts) and 8 x 460ms+340ms (1pts) initiated FT.
RF energy was delivered on posterior fascicle area during FT with the local Purkinji potential preceding QRS 18-28ms in 3 patients. In one boy the RF ablation wasn’t done because of short runs of tachycardia. In 1 pts RF ablation wasn’t done due to slow pathway ablation complication.
In patients with AVNRT and FT ablation of slow pathway was also performed.
Conclusions: fascicular tachycardia is difficult to induce. It is easier to initiat it by atrial pacing. It may be provoked by atrio-ventricular nodal tachycardia.