title: Mechanisms responsible for the initiation and maintenance of atrial fibrillation assessed by non-contact mapping system.
abstract: BACKGROUND
  This study is aimed to assess the initiation and maintenance mechanisms of atrial fibrillation (AF) and their relationships with the anatomical structures of the left atrium (LA) and pulmonary veins (PVs).
  
  
  METHODS
  Thirty-seven patients (pts; 33 men, mean age 50+/-12, range 25-68 years) with paroxysmal AF (n=29) and persistent AF (n=8) who underwent mapping of the LA and PV using 3D non-contact endocardial mapping system (EnSite 3000) were included. Atrial premature complexes (APCs) which triggered the initiation of AF lasted longer than 1 min were mapped and the activation sequence on isopotential color maps was analyzed.
  
  
  RESULTS
  Wave front dynamics and the relationship with the underlying anatomical structures were assessed. APCs from PV were related to the initiation of AF, but not to the maintenance of AF in 59.5% of the pts (focally triggered type) whereas APCs from PV not only initiated AF but also maintained AF without continuous triggering in 27% (focally driven type). Mixed type and indeterminate type of AF was in 4.5% and 13.5%, respectively. During AF, the mean number of wavelet was 1.45 (maximum 3 in 76.5%). Anatomical structures showing frequent wave break and slow conduction were mostly located at the septopulmonary bundle (86.5%) and the posterior LA roof between left superior PV and right superior PV (54.1%).
  
  
  CONCLUSIONS
  Focal repetitive activity from PV played an important role in both initiation and maintenance of AF using NCM study. Specific anatomical structures such as septopulmonary bundle or posterior LA roof were associated with the spontaneous wave break and heterogeneous conduction delay, which was also appears to be important in the maintenance of AF.
authors: Cardiovascular Center, Korea University Guro Hospital 80, Guro-dong, Guro-gu, Seoul, Korea. swrha617@yahoo.co.kr
authors: Seung-Woon
authors: SW
authors: Rha
authors: Young-Hoon
authors: YH
authors: Kim
authors: Mun Kyung
authors: MK
authors: Hong
authors: Young Moo
authors: YM
authors: Ro
authors: Cheol Ung
authors: CU
authors: Choi
authors: Soon Yong
authors: SY
authors: Suh
authors: Jin Won
authors: JW
authors: Kim
authors: Eung Ju
authors: EJ
authors: Kim
authors: Chang Gyu
authors: CG
authors: Park
authors: Hong Seog
authors: HS
authors: Seo
authors: Dong Joo
authors: DJ
authors: Oh
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery; D018780:Body Surface Potential Mapping / Q000379:methods*; D006328:Cardiac Catheterization / Q000379:methods; D017115:Catheter Ablation / Q000379:methods; D004554:Electric Countershock / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000503:physiopathology*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013614:Tachycardia, Paroxysmal / Q000175:diagnosis*