title: Local coronary flow is associated with an unsuccessful complete block line at the mitral isthmus in patients with atrial fibrillation.
abstract: BACKGROUND
  The addition of a mitral isthmus (MI) block line after pulmonary vein isolation could lead to a favorable outcome of catheter ablation in patients with atrial fibrillation (AF). However, it is sometimes tough to create a complete MI block line, and the cooling effect because of the local coronary flow may prevent the creation of a successful MI block line.
  
  
  RESULTS
  This study enrolled 81 AF patients in whom the creation of an MI block line was attempted in those with persistent or pacing-inducible AF after pulmonary vein isolation. A local coronary artery (LCA) across the MI block line was observed in 43 (53%) of 81 patients, and a bidirectional MI block was successfully accomplished in 53 (65%) of 81 patients, at the estimated MI line. The ratio of a successful MI block line was significantly lower in the patients with an LCA than in those without an LCA (42% versus 92%; P<0.001). The mean diameter of the coronary sinus (0.59 ± 0.18 versus 0.82 ± 0.22 cm; P<0.001) and length of the estimated MI line (33.4 ± 9.9 versus 29.4 ± 7.1 mm; P=0.032) were significantly shorter in the patients with a successful MI block line than in those without a successful MI block line. In the multivariable analysis, an LCA at the MI and a larger coronary sinus diameter were independent risk factors for an unsuccessful MI block line.
  
  
  CONCLUSIONS
  Local coronary flow at the MI is associated with an increased incidence of an unsuccessful MI block line.
authors: Cardiovascular Division, Shiroyama Hospital, Hibikino, Osaka, Japan. kurotobi-circ@umin.ac.jp
authors: Toshiya
authors: T
authors: Kurotobi
authors: Yoshihisa
authors: Y
authors: Shimada
authors: Naoto
authors: N
authors: Kino
authors: Katsuomi
authors: K
authors: Iwakura
authors: Koichi
authors: K
authors: Inoue
authors: Ryusuke
authors: R
authors: Kimura
authors: Yuko
authors: Y
authors: Tosyoshima
authors: Hiroya
authors: H
authors: Mizuno
authors: Yuji
authors: Y
authors: Okuyama
authors: Kenshi
authors: K
authors: Fujii
authors: Shinsuke
authors: S
authors: Nanto
authors: Issei
authors: I
authors: Komuro
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D016009:Chi-Square Distribution; D002932:Cineangiography; D017023:Coronary Angiography; D003326:Coronary Circulation; D054326:Coronary Sinus / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017548:Echocardiography, Transesophageal; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology / Q000601:surgery*; D010690:Phlebography; D011667:Pulmonary Veins / Q000503:physiopathology / Q000601:surgery; D018570:Risk Assessment; D012307:Risk Factors; D017211:Treatment Failure