RADIOFREQUENCY ABLATION OF IDIOPATHIC VENTRICULAR-TACHYCARDIA

Background: Radiofrequency ablation (RFA) has been shown to be very ef fective in the treatment of supraventricular tachycardias and has repl aced surgical ablation. Only a few reports of RFA for idiopathic ventr icular tachycardia (VT)have appeared in the literature during the last two years. Aim: This paper presents our experience with RFA for idiop athic VT in 19 patients. Material: The age range of patients was 22-60 , with a mean of 37.9 years. Twelve out of 19 were females, two patien ts had cardiac failure due to almost incessant VT while the rest had n ormal left ventricular function. Twelve patients had VT arising from t he right ventricle (RV); of these, nine were from the outflow tract, t wo 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 anterolate ral area. Methods: In all patients the diagnostic study and therapeuti c RFA were combined in a single procedure. Pacemapping was used to gui de the site of RFA in patients with VT arising from the RV. Local acti vation time (LAT), Purkinje potentials (PP) and pacemapping were used to guide RFA in those patients with LV septal tachycardias. Results: 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 R V tachycardias and all five patients with LV septal (left axis, right bundle branch block) tachycardias were successfully ablated. One patie nt with mid anterior RV VT required two attempts for successful ablati on. One patient with RV outflow tract (RVOT) VT could not be ablated d espite two attempts. Two patients with LV tachycardias arising from th e antero-lateral LV could also not be ablated. During a follow up peri od 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; fluorosco py times were four to 75, mean 26.9 minutes. Conclusion: Idiopathic VT frequently arises from the RVOT and inferobasal portion of the LV sep tum. 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 nonpharmacologic al curative treatment for symptomatic patients.