title: Insomnia and left ventricular function - an echocardiography study.
abstract: OBJECTIVE
  Recently, studies have reported an association of insomnia with incident heart failure but its causal relation is still uncertain. In patients with heart failure, the left ventricular function is impaired and the deterioration may start long before the patient experiences any symptoms. As the first study, we examined the association of insomnia with left ventricular function using state-of-the art echocardiography methods.
  
  
  METHODS
  In the echocardiography study, several indices of left ventricular function were examined in participants free from cardiovascular diseases, hypertension and diabetes. In total 788 participants with information on all relevant covariates were included. We calculated the least square mean of indices of left ventricular function associated with increasing number of insomnia symptoms (i.e. difficulties falling asleep, frequent awakenings and early awakenings), including systolic mitral annular excursion, peak velocities of systolic and diastolic motion of the mitral annulus and systolic deformation of the left ventricle.
  
  
  RESULTS
  We found no clear evidence that increasing number of insomnia symptoms is associated with any of the left ventricular function indices.
  
  
  CONCLUSIONS
  The methods that were used are sensitive to detect preclinical HF, and therefore, our findings do not support a causal relation between insomnia symptoms and HF.
authors.affiliation: a Department of Public Health and General Practice , Norwegian University of Science and Technology , Trondheim , Norway ;
authors.forename: Linn B
authors.initials: LB
authors.lastname: Strand
authors.affiliation: a Department of Public Health and General Practice , Norwegian University of Science and Technology , Trondheim , Norway ;
authors.forename: Lars E
authors.initials: LE
authors.lastname: Laugsand
authors.affiliation: b MI Lab and Department of Circulation and Medical Imaging , Norwegian University of Science and Technology , Trondheim , Norway.
authors.forename: Håvard
authors.initials: H
authors.lastname: Dalen
authors.affiliation: a Department of Public Health and General Practice , Norwegian University of Science and Technology , Trondheim , Norway ;
authors.forename: Lars
authors.initials: L
authors.lastname: Vatten
authors.affiliation: a Department of Public Health and General Practice , Norwegian University of Science and Technology , Trondheim , Norway ;
authors.forename: Imre
authors.initials: I
authors.lastname: Janszky
mesh_terms: D000368:Aged; D015984:Causality; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology; D009664:Norway / Q000453:epidemiology; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000503:physiopathology
keywords: Doppler; epidemiology; insomnia; left ventricular function; speckle tracking