title: The influence of obstructive sleep breathing disturbances on echocardiographic and pulmonary haemodynamic parameters in patients with dilated cardiomyopathy.
abstract: BACKGROUND
  It is important to identify the clinical indicators of poor prognosis and treatable conditions that might contribute to the progression of heart failure (HF) and pulmonary hypertension (PH) in the group of patients with dilated cardiomyopathy (DCM) and concomitant obstructive sleep apnoea (OSA).
  
  
  OBJECTIVE
  To evaluate the influence of OSA on echocardiographic and haemodynamic parameters in patients with DCM, and the outcome in long-term follow-up.
  
  
  METHODS
  We enrolled patients with DCM and severely impaired ejection fraction (EF < 30%). Each patient underwent polygraphy, echocardiography, and right heart catheterisation. Subjects were divided into groups based on the apnoea-hypopnoea index (AHI): > 0 and < 5 (group I), ≥ 5 and ≤ 15 (group II), > 15 and ≤ 30 (group III), and > 30 (group IV). We compared the OSA-free (AHI < 5) subjects with those with OSA (AHI ≥ 5). The evaluated clinical end-points were death and orthotropic heart transplant.
  
  
  RESULTS
  The study population comprised 51 patients. Mean EF was 22%; 59% of patients were suffering from OSA. The increased severity of OSA correlated with worse pulmonary haemodynamics. Patients with OSA had higher mean pulmonary arterial pressure and pulmonary vascular resistance than individuals without OSA (p = 0.044, p = 0.032, respectively). The highest chamber diameters assessed in echocardiography were found in group IV (p < 0.05). A total of 10 end-points occurred during follow-up (8.9 ± 5.1 months), with significant differences observed between groups I-IV and the highest rate in group IV (p < 0.001).
  
  
  CONCLUSIONS
  The increasing severity of OSA worsens the prognosis of DCM patients, independently of severe HF and coexistent PH. Systematic OSA screening in patients with HF might facilitate identification of individuals at high risk of progression of pulmonary haemodynamic impairment and end-point rate.
authors.forename: Damian
authors.initials: D
authors.lastname: Kawecki
authors.forename: Celina
authors.initials: C
authors.lastname: Wojciechowska
authors.forename: Wojciech
authors.initials: W
authors.lastname: Jacheć
authors.forename: Krystyna
authors.initials: K
authors.lastname: Krzemień-Wolska
authors.forename: Janusz
authors.initials: J
authors.lastname: Dola
authors.forename: Wojciech
authors.initials: W
authors.lastname: Ścierski
authors.forename: Izabela
authors.initials: I
authors.lastname: Kawecka
authors.forename: Andrzej
authors.initials: A
authors.lastname: Tomasik
authors.forename: Tomasz
authors.initials: T
authors.lastname: Brzostowicz
authors.affiliation: 2nd Department of Cardiology in Zabrze, Medical University of Silesia, Katowice, Poland. beamorawiec@wp.pl.
authors.forename: Beata
authors.initials: B
authors.lastname: Morawiec
authors.forename: Ewa
authors.initials: E
authors.lastname: Nowalany-Kozielska
mesh_terms: D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000150:complications*; D018450:Disease Progression; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D006439:Hemodynamics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D020181:Sleep Apnea, Obstructive / Q000150:complications*
keywords: dilated cardiomyopathy; heart failure; obstructive sleep apnoea; pulmonary hypertension