title: Novel method to evaluate the conduction velocity and conducting area during isthmus-dependent atrial flutter.
abstract: OBJECTIVE
  The difference of the conduction velocity (CV) around the tricuspid valve annulus between the counter-clockwise (CCW) atrial flutter and the clockwise (CW) atrial flutter has not been well clarified. This study was undertaken to evaluate the CV and the conducting area (CA) per millisecond around the tricuspid valve annulus using the electroanatomical mapping.
  
  
  METHODS
  The electroanatomical mapping was performed during the tachycardia for 30 consecutive patients (mean age: 61±16 years) with isthmus-dependent atrial flutter (CCW, 25; CW, 5). We measured the CV and the CA of five divided areas of the right atrium, that is, upper septum (US), lower septum (LS), isthmus (I), upper lateral wall (UL) and lower lateral wall (LL) using the novel measurement method in the isochronal map. Statistical differences of these data between the two groups were assessed by the Student's t-test and one-way analysis of variance methods.
  
  
  RESULTS
  In total, the CV of the LS was significantly slower than other areas (m/sec: US, 0.57±0.18; LS, 0.43±0.18; UL, 0.60±0.26; LL, 0.53±0.20; I, 0.50±0.17; p<0.05) and the CA of the US and UL were significantly larger than other areas (mm2/sec: US, 34.5±16.2; LS, 16.2±9.5; UL, 40.0±14.1; LL, 27.0±17.0; I, 16.8±8.5; p<0.0001). There was no significant difference between the CCW and the CW atrial flutters in terms of the CV and the CA of equally divided five areas.
  
  
  CONCLUSIONS
  In both of the CCW and the CW atrial flutters, the CV of the LS was significantly slower than other areas and the CA of the lower atrium was significantly smaller than the upper atrium.
authors.affiliation: Department of Cardiology, Faculty of Medicine, Sivas Cumhuriyet University, Sivas, Turkey.
authors.forename: Alim
authors.initials: A
authors.lastname: Erdem
authors.forename: Ebru
authors.initials: E
authors.lastname: Gölcük
authors.forename: Zekeriya
authors.initials: Z
authors.lastname: Küçükdurmaz
authors.forename: Ritsushi
authors.initials: R
authors.lastname: Kato
authors.forename: Motoki
authors.initials: M
authors.lastname: Hara
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tobiume
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishida
authors.forename: Masahiro
authors.initials: M
authors.lastname: Uenishi
authors.forename: Yurika
authors.initials: Y
authors.lastname: Ishizuka
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Komiyama
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Nishimura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D020517:Atrial Appendage; D001282:Atrial Flutter / Q000503:physiopathology*; D018780:Body Surface Potential Mapping / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D014261:Tricuspid Valve