RADIOFREQUENCY CATHETER ABLATION OF POSTEROSEPTAL ATRIOVENTRICULAR PATHWAYS - LOCATION-SPECIFIC ELECTROGRAPHIC CHARACTERISTICS OF SUCCESSFUL ABLATION SITES

The electrographic features of successful sites of radiofrequency cath eter ablation were analyzed in 33 cases of posteroseptal accessory pat hways and compared with those from 155 cases of free wall accessory pa thways. The atrioventricular intervals in the posteroseptal cases were significantly longer than in the free wall cases (posteroseptal vs le ft and right free wall, 38 vs 33 and 26 msec, respectively; p<0.05), a nd the incidences of continuous electrograms (42 vs 63 and 79%; p<0.01 ) and PQS-pattern unipolar electrograms (50 vs 76 and 78%: p<0.05) wer e significantly lower in the posteroseptal cases. The V-delta interval s in the posteroseptal cases were significantly longer than in the lef t free wall cases (17 vs 13 msec: p<0.05), but shorter than in the rig ht free wall cases (17 vs 23 msec; p<0.05). No statistically significa nt difference in the incidence of Kent potentials among the 3 groups w as observed. In radiofrequency ablation of posteroseptal pathways, the length of the atrioventricular interval and the incidences of continu ous electrograms and PQS-pattern unipolar electrograms may be unsatisf actory even at the appropriate target site, but the V-delta interval a nd Kent potential are good indicators of suitable target sites.