title: Clinical significance of awake oscillatory ventilation in patients with heart failure and effects of open-heart surgery.
abstract: BACKGROUND
  Although sleep apnea has recently become a concern in patients with congestive heart failure (CHF), some patients with CHF exhibit characteristic oscillatory ventilation (OV) even when they are awake. We investigated the clinical significance of OV in patients with CHF, and effects of open-heart surgery on the OV.
  
  
  OBJECTIVE
  OV is an indicator of the severity of CHF, and this abnormal respiratory pattern improves with hemodynamic changes after open-heart surgery.
  
  
  METHODS
  According to respiratory pattern in the cardiopulmonary exercise testing (CPX) before cardiac surgery, 50 patients with CHF were divided into 14 patients of OV-positive (OV+) and 36 patients of OV-negative (OV-). Then, the several indices of CPX before surgery, 1 week and 6 months after surgery were compared between the 2 groups.
  
  
  RESULTS
  The peak VO2 before surgery was lower in OV+ patients than those in OV- patients (15.3 vs 18.8 m1/min/kg, p < 0.05). One week after surgery, anaerobic threshold (AT) and end-tidal C02 (ETC02) were lower in OV+ patients than those in OV- patients (AT: 9.5 vs 10,7 ml/min/kg, p < 0.05, ETCO2: 5.3 vs 5.6%, p < 0.05). However, 6 months after surgery, the statistical differences of these CPX parameters between the 2 groups were not found, and OV disappeared in 79% of OV+ patients.
  
  
  CONCLUSIONS
  These data suggest that OV is an indicator of the severity of CHF, and gradually improved with the open-heart surgery.
authors.affiliation: EBM Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan. k ueshima@pbh.med.kyoto-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Ueshima
authors.forename: Noboru
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Masahiko
authors.initials: M
authors.lastname: Saitoh
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Nakamura
authors.forename: Kazuwa
authors.initials: K
authors.lastname: Nakao
mesh_terms: D015308:Anaerobic Threshold; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012123:Pulmonary Ventilation; D015656:Respiratory Mechanics; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014851:Wakefulness