title: Effects of continuous positive airway pressure therapy on right ventricular function assessment by tissue Doppler imaging in patients with obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  The effects of continuous positive airway pressure (CPAP) therapy on right ventricular (RV) function in patients with obstructive sleep apnea syndrome (OSAS) has not been previously studied by tissue Doppler imaging (TDI). The aim of this study was to assess RV function using TDI in patients with OSAS before and after CPAP therapy.
  
  
  METHODS
  Twenty-eight patients with newly diagnosed OSAS in the absence of any confounding factors and 18 controls were included in this study. The peak systolic velocity (S'm), early (E'm) and late (A'm) diastolic myocardial peak velocities at tricuspid lateral annulus, isovolumic acceleration (IVA), myocardial precontraction time (PCT'm), myocardial contraction time (CT'm), and myocardial relaxation time (RT'm) were measured. All echocardiographic parameters were calculated 6 months after CPAP therapy.
  
  
  RESULTS
  The RV diastolic parameters such as E'm velocity and E'm-to-A'm ratio were significantly lower, RT'm was significantly prolonged, A'm velocity was similar in patients with OSAS compared to controls; and the RV systolic parameters such as IVA and CT'm were significantly lower and S'm was similar in patients with OSAS compared to controls. At the end of the treatment, 20 of 28 patients were compliant with CPAP therapy. E'm velocity, E'm-to-A'm ratio, IVA, and CT'm increased, PCT'm, PCT'm-to-CT'm ratio, and RT'm decreased significantly after therapy, whereas S'm velocity and A'm velocity did not change after CPAP treatment in the compliant patients.
  
  
  CONCLUSIONS
  OSAS is associated with RV systolic and diastolic dysfunction, and 6 months of CPAP therapy improves the RV systolic and diastolic dysfunction.
authors.affiliation: Department of Cardiology, Ataturk Education and Research Hospital, Ankara, Turkey. drnihkar@yahoo.co.uk
authors.forename: Nihal Akar
authors.initials: NA
authors.lastname: Bayram
authors.forename: Bulent
authors.initials: B
authors.lastname: Ciftci
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Bayram
authors.forename: Telat
authors.initials: T
authors.lastname: Keles
authors.forename: Tahir
authors.initials: T
authors.lastname: Durmaz
authors.forename: Murat
authors.initials: M
authors.lastname: Akcay
authors.forename: Ekrem
authors.initials: E
authors.lastname: Yeter
authors.forename: Engin
authors.initials: E
authors.lastname: Bozkurt
mesh_terms: D000328:Adult; D045422:Continuous Positive Airway Pressure; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012015:Reference Standards; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D018497:Ventricular Dysfunction, Right / Q000503:physiopathology / Q000628:therapy*