title: Left ventricular systolic and diastolic function in obstructive sleep apnea: impact of continuous positive airway pressure therapy.
abstract: BACKGROUND
  Previous studies in obstructive sleep apnea (OSA) were limited by study cohorts with comorbidities that confound assessment of left ventricular (LV) systolic and diastolic function. We comprehensively evaluated LV function using 2-dimensional echocardiography (2DE), tissue Doppler imaging (TDI), and 3-dimensional echocardiography (3DE) in subjects moderate-severe OSA, who were compared with disease (patients with hypertension, no OSA) and healthy control subjects.
  
  
  RESULTS
  A total of 120 subjects (n=40 each of matched OSA, hypertension and healthy cohorts) underwent echocardiographic examination for the assessment of septal and posterior wall thickness, LV mass index, LV volumes and ejection fraction, mitral valve inflow indices (E, A), mitral annular velocity (S, E'), and left atrial volume index (LAVI). OSA subjects were treated with continuous positive airway pressure (mean duration of 26 weeks), after which the echocardiographic parameters were reassessed. Posterior wall thickness and LV mass index were significantly higher in OSA and hypertensive groups compared with healthy. Systolic S velocity was reduced in OSA and hypertensive compared with healthy control subjects (P<0.05). Diastolic function (E/A, IVRT, and E/E') was impaired in both OSA and hypertensive groups. On 3DE, mean LAVI was significantly greater in OSA and hypertensive compared with healthy. In OSA patients, continuous positive airway pressure therapy resulted in reduction of the posterior wall thickness (P=0.02) and improvement in LV ejection fraction (P<0.05), systolic S velocity (P<0.05), and diastolic LV impairment parameters.
  
  
  CONCLUSIONS
  Moderate to severe OSA causes structural and functional changes in V function and are comparable to that seen in hypertension. These abnormalities significantly improve after CPAP therapy.
authors.affiliation: University of Birmingham Centre for Cardiovascular Sciences and the Department of Respiratory Medicine, City Hospital, Birmingham, United Kingdom.
authors.forename: Mehmood
authors.initials: M
authors.lastname: Butt
authors.forename: Girish
authors.initials: G
authors.lastname: Dwivedi
authors.forename: Alena
authors.initials: A
authors.lastname: Shantsila
authors.forename: Omer A
authors.initials: OA
authors.lastname: Khair
authors.forename: Gregory Y H
authors.initials: GY
authors.lastname: Lip
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000379:methods*; D003971:Diastole; D018450:Disease Progression; D015150:Echocardiography, Doppler; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011379:Prognosis; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left / Q000502:physiology*