Radiofrequency ablation of idiopathic ventricular tachycardia

Radiofrequency ablation (RFA) has been shown to be very effective in the treatment of supraventricular tachycardias and has replaced surgical ablation. Only a few reports of RFA for idiopathic ventricular tachycardia (VT) have appeared in the literature during the last two years.

This paper presents our experience with RFA for idiopathic VT in 19 patients.

The age range of patients was 22-60, with a mean of 37.9 years. Twelve out of 19 were females, two patients had cardiac failure due to almost incessant VT while the rest had normal left ventricular function. Twelve patients had VT arising from the right ventricle (RV); of these, nine were from the outflow tract, two from the RV apex, and one from the mid-anterior RV. Seven patients had VT arising from the left ventricle (LV); of these, five were from the inferobasal portion of the septum and two were from the anterolateral area.

In all patients the diagnostic study and therapeutic RFA were combined in a single procedure. Pacemapping was used to guide the site of RFA in patients with VT arising from the RV. Local activation time (LAT), Purkinje potentials (PP) and pacemapping were used to guide RFA in those patients with LV septal tachycardias.

A total of 21 RF procedures were performed in 19 patients and 15 out of 19 patients had successful VT ablation. Ten of the 12 patients with RV tachycardias and all five patients with LV septal (left axis, right bundle branch block) tachycardias were successfully ablated. One patient with mid anterior RV VT required two attempts for successful ablation. One patient with RV outflow tract (RVOT) VT could not be ablated despite two attempts. Two patients with LV tachycardias arising from the antero-lateral LV could also not be ablated. During a follow up period of two to 16 months none of the successful patients had recurrence of VT. The number of RF applications was one to 27, mean 10; fluoroscopy times were four to 75, mean 26.9 minutes.

Idiopathic VT frequently arises from the RVOT and inferobasal portion of the LV septum. These tachycardias can be diagnosed on clinical and ECG grounds. RFA for idiopathic VT arising from these areas has a high success rate and this mode of treatment should be considered as a nonpharmacological curative treatment for symptomatic patients.