VALUE OF LOCAL ELECTROGRAM CHARACTERISTICS PREDICTING SUCCESSFUL CATHETER ABLATION OF LEFT-SIDED VERSUS RIGHT-SIDED ACCESSORY ATRIOVENTRICULAR PATHWAYS BY RADIOFREQUENCY CURRENT

Despite similar guidance by local electrogram criteria, catheter ablat ion of right-sided accessory atrioventricular (AV) pathways by radiofr equency current has been less effective than that of left-sided ones. In order to elucidate the possible diversities in local electrosignal criteria, we systematically analyzed the morphological and timing char acteristics of 215 bipolar local electrograms from catheter ablation s ites of 65 left-sided accessory AV pathways and of 356 from those of 3 7 right-sided ones in 92 consecutive patients with Wolff-Parkinson-Whi te syndrome or AV reentrant tachycardia incorporating concealed access ory pathway potential, local ventricular activation preceding QRS comp lex for 20 ms or more during ventricular insertion mapping and the loc al retrograde ventriculoatrial (VA) continuity, local retrograde VA in terval less than or equal to 50 ms, electrogram stability (left-sided targets only), retrograde accessory pathway potential (right-sided tar gets only) during atrial insertion mapping, as independent local elect rogram predictors for successful ablation of left- and right-sided acc essory AV pathways. Combination of all local electrogram predictors co uld have moderate chance of success (80 and 51%) for the ventricular a nd atrial insertion ablation of left-sided accessory AV pathways, but only low probability of success (40% in ventricular insertion ablation ) or very low sensitivity (12.5% in atrial insertion ablation) for rig ht-sided ones. In conclusion, with the present approach, successful ca theter ablation of right-sided accessory AV pathways, compared to left -sided ones, still necessitate a breakthrough in the precision mapping and the efficiency of energy delivery.