RADIOFREQUENCY ABLATION FOR WPW SYNDROME WITH MONITORING THE LOCAL ELECTROGRAM AT THE ABLATION SITE

Catheter ablation for septal accessory pathways is occasionally associ ated with complications, such as atrioventricular block, since the sep tal region is a complex anatomical structure containing the atrioventr icular conduction system. Therefore, we designed a signal separator co mposed of an inductance-capacitance network with which the local elect rogram at the ablation site could be continuously monitored during the delivery of radiofrequency (RF) energy. We tested the safety and effi cacy of RF catheter ablation using a signal separator in 17 patients w ith septal accessory pathways (10 anteroseptal and 7 midseptal cases). RF energy (520 KHz) was applied at an output of 20-40 W for 30-120 se c. to the atrioventricular annulus where the shortest atrioventricular interval or accessory pathway potential was recorded on the electrogr am using a large tip ablation electrode. In ablation for the anterosep tal or midseptal accessory pathways, the atrial to ventricular amplitu de ratio on the local electrogram was maintained at 1 or less during t he delivery of RF energy. In all 17 cases, the interruption of accesso ry pathways was successful without atrioventricular block. In one pati ent, accessory pathway conduction recurred which could be treated by t he second session. There were no late complications during the 4 to 46 month follow-up period. In conclusion, RF catheter ablation using a s ignal separator is a safe and reliable method for treating patients wi th septal accessory pathways.