title: Relation between oscillatory breathing and cardiopulmonary function during exercise in cardiac patients.
abstract: BACKGROUND
  Oscillatory breathing, alternating between hyperpnea and hypopnea, has been recognized in cardiac patients, especially in those with heart failure. We evaluated whether the cycle length and amplitude of oscillatory breathing correlate with impaired cardiopulmonary function during exercise.
  
  
  RESULTS
  We analyzed respiratory gas data during cardiopulmonary exercise testing (CPX) in 17 cardiac patients (68 ± 12 years) who showed clear oscillatory ventilation during CPX. The cycle length (time from peak to peak) and the amplitude (difference between peak and nadir) for both oscillating ventilation (VE) and oscillating O(2) uptake (VO(2)) were calculated from several consecutive oscillations noted at rest, and compared with indices of CPX. Oscillating VO(2) preceded oscillating VE in 16 of the 17 patients. Peak VO(2) (10.3 ± 3.1 ml min(-1)kg(-1)) correlated significantly negatively with the cycle length of the VE oscillation (r=-0.60, P=0.010), and of the VO(2) oscillation (r=-0.61, P=0.008), and the difference in time between the peak of oscillating VE and the corresponding peak of VO(2) (r=-0.58, P=0.012). Similarly, the slope of the increase in VE to the increase in CO(2) output (45.6 ± 11.5) correlated significantly positively with the cycle length of the VE and VO(2) oscillations (r=0.68, P=0.002; r=0.67, P=0.003, respectively).
  
  
  CONCLUSIONS
  The cycle length of oscillatory breathing is closely related to impaired cardiac reserve during exercise in cardiac patients.
authors.affiliation: Cardiovascular Institute, Tokyo 106-0031, Japan.
authors.forename: Jo
authors.initials: J
authors.lastname: Kato
authors.forename: Akira
authors.initials: A
authors.lastname: Koike
authors.forename: Masayo
authors.initials: M
authors.lastname: Hoshimoto-Iwamoto
authors.forename: Osamu
authors.initials: O
authors.lastname: Nagayama
authors.forename: Koji
authors.initials: K
authors.lastname: Sakurada
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamashita
authors.forename: Karlman
authors.initials: K
authors.lastname: Wasserman
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002245:Carbon Dioxide / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006333:Heart Failure / Q000503:physiopathology* / Q000534:rehabilitation*; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012119:Respiration; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen