title: Severe obstructive sleep apnea is associated with left ventricular diastolic dysfunction.
abstract: BACKGROUND
  Hypertension is common in patients with obstructive sleep apnea (OSA). However, the effect of OSA on ventricular function, especially diastolic function, is not clear. Therefore, we have assessed the prevalence of diastolic dysfunction in patients with OSA and the relationship between diastolic parameters and severity of OSA.
  
  
  METHODS
  Sixty-eight consecutive patients with OSA confirmed by polysomnography underwent echocardiography. Diastolic function of the left ventricle was determined by transmitral valve pulse-wave Doppler echocardiography. Various baseline characteristics, severity of OSA, and echocardiographic parameters were compared between patients with and without diastolic dysfunction.
  
  
  RESULTS
  There were 61 male and 7 female patients with a mean age of 48.1 +/- 11.1 years, body mass index of 28.5 +/- 4.3 kg/m(2), and apnea/hypopnea index (AHI) of 44.3 +/- 23.2/h (mean +/- SD). An abnormal relaxation pattern (ARP) in diastole was noted in 25 patients (36.8%). Older age (52.7 +/- 8.9 years vs 45.1 +/- 11.3 years, p = 0.005), hypertension (56% vs 20%, p = 0.002), and a lower minimum pulse oximetric saturation (SpO(2)) during sleep (70.5 +/- 17.9% vs 78.8 +/- 12.9%, respectively; p = 0.049) were more common in patients with ARP. By multivariate analysis, minimum SpO(2) < 70% was an independent predictor of ARP (odds ratio, 4.34; 95% confidence interval, 1.23 to 15.25; p = 0.02) irrespective of age and hypertension. Patients with AHI > or = 40/h had significantly longer isovolumic relaxation times than those with AHI < 40/h (106 +/- 19 ms vs 93 +/- 17 ms, respectively; p = 0.005).
  
  
  CONCLUSIONS
  Diastolic dysfunction with ARP was common in patients with OSA. More severe sleep apnea was associated with a higher degree of left ventricular diastolic dysfunction in this study.
authors.affiliation: Division of Cardiology, Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
authors.forename: Jeffrey W H
authors.initials: JW
authors.lastname: Fung
authors.forename: Thomas S T
authors.initials: TS
authors.lastname: Li
authors.forename: Dominic K L
authors.initials: DK
authors.lastname: Choy
authors.forename: Gabriel W K
authors.initials: GW
authors.lastname: Yip
authors.forename: Fanny W S
authors.initials: FW
authors.lastname: Ko
authors.forename: John E
authors.initials: JE
authors.lastname: Sanderson
authors.forename: David S C
authors.initials: DS
authors.lastname: Hui
mesh_terms: D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000503:physiopathology; D018754:Ventricular Dysfunction / Q000209:etiology*