title: Electroanatomically estimated length of slow pathway  in atrioventricular nodal reentrant tachycardia.
abstract: The length of the slow pathway (SP-L) in atrioventricular (AV) nodal reentrant tachycardia (NRT) has never been measured clinically. We studied the relationship among (a) SP-L, i.e., the distance between the most proximal His bundle (H) recording and the most posterior site of radiofrequency (RF) delivery associated with a junctional rhythm, (b) the length of Koch’s triangle (Koch-L), (c) the conduction time over the slow pathway (SP-T), measured by the AH interval during AVNRT at baseline, and (d) the distance between H and the site of successful ablation (SucABL-L) in 26 women and 20 men (mean age 64.6 ± 11.6 years), using a stepwise approach and an electroanatomic mapping system (EAMS). SP-L (15.0 ± 5.8 mm) was correlated with Koch-L (18.6 ± 5.6 mm; R 2 = 0.1665, P < 0.005), SP-T (415 ± 100 ms; R 2 = 0.3425, P = 0.036), and SucABL-L (11.6 ± 4.7 mm; R 2 = 0.5243, P < 0.0001). The site of successful ablation was located within 10 mm of the posterior end of the SP in 38 patients (82.6 %). EAMS-guided RF ablation, using a stepwise approach, revealed individual variations in SP-L related to the size of Koch’s triangle and AH interval during AVNRT. Since the site of successful ablation was also correlated with SP-L and was usually located near the posterior end of the SP, ablating anteriorly, away from the posterior end, is not a prerequisite for the success of ablation procedures.
authors.affiliation: Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
authors.forename: Tadanobu
authors.initials: T
authors.lastname: Irie
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nakajima
authors.forename: Masaki
authors.initials: M
authors.lastname: Ota
authors.forename: Takafumi
authors.initials: T
authors.lastname: Iijima
authors.forename: Mio
authors.initials: M
authors.lastname: Tamura
authors.forename: Takashi
authors.initials: T
authors.lastname: Iizuka
authors.forename: Shuntaro
authors.initials: S
authors.lastname: Tamura
authors.forename: Akihiro
authors.initials: A
authors.lastname: Saito
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kurabayashi
mesh_terms: D000328:Adult; D001283:Atrioventricular Node / Q000503:physiopathology; D002036:Bundle of His / Q000473:pathology / Q000503:physiopathology / Q000528:radiation effects; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D016896:Treatment Outcome