[Radiofrequency catheter ablation of ventricular tachycardia in patients without apparent structural cardiopathy].

BACKGROUND AND PURPOSE

It has been suggested that the efficacy of radiofrequency ablation of idiopathic ventricular tachycardia (VT) is dependent on the site of VT origin, with the efficacy being greater for VTs originating from right ventricle. The electrophysiologic characteristic and the results of radiofrequency catheter ablation of ventricular tachycardia in patients without structural heart disease are reported. Special emphasis was focused to the differences observed in the pace and activating mapping between VTs originating in the right ventricle and those originating from the left ventricle and its possible implications for radiofrequency efficacy.

METHODS AND RESULTS

14 consecutive patients with idiopathic VT (7 women and 7 men, mean age 35 +/- 16 years), 8 originating in the right ventricle (RV) and 6 in the left ventricle (LTV), underwent catheter ablation using radiofrequency energy. The observation of entrainment with fusion in all LV VT suggested that the electrophysiologic mechanism was a reentry, meanwhile the RV VT were due to focal non-reentrant mechanisms. Sites for radiofrequency energy delivery were selected on the basis of pace and activation mapping in all patients less in two patients with incessant VT in whom only activation mapping was performed. 14 VT were mapped. The activation mapping demonstrated isolated presystolic electrograms in the point of origin in all VT arising from the LV. However in RV tachycardias there was continuous activity between presystolic and systolic electrograms, although the prematurity of these electrograms was similar (31 +/- 16 ms vs 33 +/- 9 ms; p = 0.77). Radiofrequency was successful in eliminating 93% of TV (100% RV TV vs 83% LV TV; p = 0.23). No complications were observed.

CONCLUSIONS

The results of this study suggest that radiofrequency ablation is highly successful either in right and left ventricles idiopathic tachycardias when pace and activation mapping are used complementary.