EFFECT OF RADIOFREQUENCY CATHETER ABLATION ON PARASYMPATHETIC DENERVATION - A COMPARISON OF 3 DIFFERENT ABLATION SITES

Radiofrequency (RF) catheter ablation of supraventricular tachycardias (SVT) has been shown to result in local parasympathetic denervation. The purpose of this study was to estimate the correlation between RF c umulative energy and parasympathetic denervation at three different ab lation sites. Methods: 45 patients who underwent RF ablation of 36 AV reentrant tachycardias and 9 AV nodal reentrant tachycardias were stud ied. Twenty patients had left free-wall accessory pathways (group L), 8 patients right free-wall accessory pathways (group R), and 17 patien ts septal accessory pathways (n = 8) or slow pathways (n = 9) (group ) . Time and frequency domain analysis of heart rate variability on 24-h our ambulatory ECG recordings was performed before and after RF ablati on. pNN50 and the high frequency (0.15 to 0.40 Hz, HF) component were measured to examine the effects on parasympathetic nerve activity. The values of Delta pNN50 and Delta HF were expressed as the percent chan ge of pNN50 and HF that occurred after versus before RF ablation. Resu lts: Both pNN50 and HF significantly decreased after RF ablation in al l three groups. In group S, there was a significant correlation betwee n RF cumulative energy and Delta pNN50 (r = 0.66, P < 0.01) or Delta H F (r = 0.58, P < 0.05). In contrast, there was no correlation between RF cumulative energy and Delta pNN50 or Delta HF in either group L or group R. Conclusion: These data suggest that RF ablation produces para sympathetic denervation at all three sites along the mitral or tricusp id annulus and that parasympathetic fibers may be located predominantl y in the septal area.