title: Incidence and mechanism of dislocated fast pathway in various forms of atrioventricular nodal reentrant tachycardia.
abstract: BACKGROUND
  The incidence and mechanism of the dislocated antegrade fast pathway (A-FP) were examined in various forms of atrioventricular nodal reentrant tachycardia (AVNRT).
  
  
  RESULTS
  To localize the A-FP, 5 atrial sites comprising the inferior coronary sinus ostium (CSOS), apex of the triangle of Koch (A-TOK), and 3 equidistant sites on the atrioventricular junction extending from A-TOK to CSOS (site S, M, and I) were pace mapped at 100 beats/min in 71 patients with slow-fast (n=49), fast-slow (n=7) and slow-intermediate (n=15) forms of AVNRT. The site with the shortest interval between the stimulus and His potential recorded at the A-TOK (shortest St-H) was defined as the A-FP site. The A-FP was located at A-TOK in 31 patients (nondislocated group), and inferior to A-TOK in 40 patients (site S in 26, M in 13, and I in one patient; dislocated group). There was no significant difference in the location of the A-FP among the 3 forms of AVNRT. Although the shortest St-H did not differ between groups, the St-H at A-TOK in the dislocated group was significantly longer than that in the nondislocated group. Additionally, the His potential preceding that of the A-TOK was observed more frequently inferior to the A-TOK in the dislocated group than in the nondislocated group, suggesting that the A-FP dislocation was accompanied by displacement of the His bundle.
  
  
  CONCLUSIONS
  Dislocated A-FP was frequently and uniformly observed among various forms of AVNRT, and is probably caused by inferior displacement of the entire atrioventricular node - His bundle apparatus.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Hiroshige
authors.initials: H
authors.lastname: Yamabe
authors.forename: Kenji
authors.initials: K
authors.lastname: Morihisa
authors.forename: Takashi
authors.initials: T
authors.lastname: Uemura
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawano
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Nagayoshi
authors.forename: Sunao
authors.initials: S
authors.lastname: Kojima
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001283:Atrioventricular Node / Q000503:physiopathology*; D002036:Bundle of His / Q000503:physiopathology; D017115:Catheter Ablation / Q000379:methods; D002648:Child; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology* / Q000601:surgery