title: Assessment of the relationship between right ventricular function and the severity of obstructive sleep-disordered breathing.
abstract: BACKGROUND
  Some complications of obstructive sleep-disordered breathing (OSDB), such as heart failure including right ventricular (RV) overload, are more serious than an increase of the apnea-hypopnea index (AHI) or respiratory disturbance index (RDI). These serious complications may contribute to the worsening of OSDB.
  
  
  OBJECTIVE
  To explore the relationship between RV function in OSDB patients while awake and the severity of OSDB.
  
  
  METHODS
  Fifty-eight patients were evaluated to determine the cause of OSDB and were subjected to various examinations, including cardiac ultrasonography. Of them, 54 were included in this analysis.
  
  
  RESULTS
  Isovolumetric relaxation time decreased as AHI increased to about 40 events/h and increased when AHI increased beyond 40 events/h. The total ejection isovolume index increased as AHI increased to approximately 35 events/h and decreased when AHI increased beyond 35 events/h.
  
  
  CONCLUSIONS
  RV function gradually deteriorated from the early stages of obstructive sleep apnea syndrome, even though there was no apparent increase in pulmonary artery pressure. The results of this study indicated that the progression of OSDB correlated with RV function determined in patients while awake. Further studies are required to clarify this relationship, including assessment of components of RV function.
authors.affiliation: Department of Respiratory Medicine, Chiba-Hokusoh Hospital, Nippon Medical School, Inzai, Chiba, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Hino
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Mizuno
authors.forename: Akihiko
authors.initials: A
authors.lastname: Gemma
mesh_terms: D018618:Echocardiography, Doppler, Color; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011379:Prognosis; D011669:Pulmonary Wedge Pressure; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D016278:Ventricular Function, Right
keywords: circulation; pulsed Doppler echocardiography; right ventricle echocardiography; right ventricular function; sleep