title: Left atrial volume: predictor of atrial fibrillation in patients with degenerative mitral regurgitation.
abstract: OBJECTIVE
  In patients with mitral regurgitation (MR) due to degenerative mitral valve prolapse (MVP), preoperative atrial fibrillation (AF) has been identified as an independent predictor of survival after surgery for MR. Thus, the determinants of preoperative AF may have critical implications to evaluate the timing of mitral valve repair. The study aim was to investigate the role of left atrial (LA) volume in predicting preoperative AF in patients with severe MR due to degenerative MVP.
  
  
  METHODS
  Sixty-six patients with severe degenerative MR (regurgitant volume > or =60 ml, regurgitant fraction > or =50%, effective regurgitant orifice area > or =0.4 cm(2)) in sinus rhythm (SR) at diagnosis and conservatively managed were eligible for the study. Complete two-dimensional (2-D) echocardiographic and Doppler measurements, including the measurement of maximum LA volume, were performed in all patients.
  
  
  RESULTS
  During follow up under conservative management (18.1+/-4.8 months), eight patients (12%) experienced conversion to AF, and 58 remained in SR. The mean LA dimension was 4.0+/-0.5 cm in patients with SR, and 5.1+/-0.8 cm in those who developed AF (p <0.0001). The mean LA volume and LA volume index (indexed to body surface area) were 95 +/-23 ml and 60+/-14 ml/m(2) respectively in patients with SR, and 166+/-66 ml and 104+/-42 ml/m(2) respectively in those who developed AF (both p <0.0001). The optimal cut-off value for LA volume to predict AF conversion was 117.5 ml (sensitivity 88%, specificity 83%), and for LA volume index was 75 ml/m(2) (sensitivity 88%, specificity 88%).
  
  
  CONCLUSIONS
  LA volume measurement should be considered in patients with degenerative severe MR diagnosed in SR. A LA volume index > or =75 ml/m(2) reflects the risk of subsequent AF, and patients should be closely monitored.
authors.affiliation: Division of Cardiology, Kobe General Hospital, 4-6 Minatojima-nakamachi, Cyuo-ku, Kobe 650-0046, Japan. ktanabe@leto.eonet.ne.jp
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Tanabe
authors.forename: Kazuto
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tani
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yagi
authors.forename: Minako
authors.initials: M
authors.lastname: Katayama
authors.forename: Koichi
authors.initials: K
authors.lastname: Tamita
authors.forename: Makoto
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Kaji
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamamuro
authors.forename: Shigefumi
authors.initials: S
authors.lastname: Morioka
authors.forename: Yukikatsu
authors.initials: Y
authors.lastname: Okada
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Kihara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000209:etiology*; D002306:Cardiac Volume; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000209:etiology / Q000601:surgery*; D008945:Mitral Valve Prolapse / Q000150:complications; D009929:Organ Size; D011300:Preoperative Care; D012306:Risk; D014463:Ultrasonography