title: Spectral analysis of the heart sounds in children with and without pulmonary artery hypertension.
abstract: BACKGROUND
  Pulmonary artery hypertension (PAH) is difficult to recognize clinically. Digital stethoscopes offer an opportunity to re-evaluate the diagnosis of PAH. We hypothesized that spectral analysis of heart sound frequencies using recordings from a digital stethoscope would differ between children with and without PAH.
  
  
  METHODS
  We recorded heart sounds using a digital stethoscope from 27 subjects (12 males) with a median age of 7 years (3 months to 19 years) undergoing simultaneous cardiac catheterization. 13 subjects had a mean pulmonary artery pressure (mPAp)<25 mm Hg (8-24 mm Hg). 14 subjects had a mPAp≥25 mm Hg (25-97 mm Hg). We applied the fast Fourier transform, power spectral analysis, separability testing, and linear discriminant analysis with leave-one-out cross-validation to the heart sounds recorded from the cardiac apex and 2nd left intercostal space (LICS) to examine the frequency domain. The significance of the results was determined using a t-test and rank-sum test.
  
  
  RESULTS
  The relative power of the frequencies 21-22 Hz of the heart sounds recorded at the 2nd LICS was decreased significantly in subjects mPAp≥25 mm Hg versus<25 mm Hg.
  
  
  CONCLUSIONS
  Heart sound signals of patients with PAH contain significantly less relative power in the band 21-22 Hz compared to subjects with normal PAp. Information contained in the frequency domain may be useful in diagnosing PAH and aid the development of auscultation based techniques for diagnosing PAH. In the future, utilizing the diagnostic information contained in heart sounds recordings may require analysis of both the time and frequency domains.
authors.affiliation: Department of Mathematics and Computing Science, University of Alberta, Edmonton, Canada.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Elgendi
authors.affiliation: Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Mazankowski Alberta Heart Institute, Edmonton, Canada.
authors.forename: Prashant
authors.initials: P
authors.lastname: Bobhate
authors.affiliation: Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Mazankowski Alberta Heart Institute, Edmonton, Canada.
authors.forename: Shreepal
authors.initials: S
authors.lastname: Jain
authors.affiliation: Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Mazankowski Alberta Heart Institute, Edmonton, Canada.
authors.forename: Long
authors.initials: L
authors.lastname: Guo
authors.affiliation: Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Mazankowski Alberta Heart Institute, Edmonton, Canada.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rutledge
authors.affiliation: Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Mazankowski Alberta Heart Institute, Edmonton, Canada.
authors.forename: Yashu
authors.initials: Y
authors.lastname: Coe
authors.affiliation: Department of Biomedical Electrical and Computer Engineering, University of Alberta, Edmonton, Canada.
authors.forename: Roger
authors.initials: R
authors.lastname: Zemp
authors.affiliation: Department of Mathematics and Computing Science, University of Alberta, Edmonton, Canada.
authors.forename: Dale
authors.initials: D
authors.lastname: Schuurmans
authors.affiliation: Department of Pediatrics, Stollery Children's Hospital, University of Alberta, Mazankowski Alberta Heart Institute, Edmonton, Canada. Electronic address: iadatia@ualberta.ca.
authors.forename: Ian
authors.initials: I
authors.lastname: Adatia
mesh_terms: D000293:Adolescent; D006328:Cardiac Catheterization / Q000379:methods; D002648:Child; D002675:Child, Preschool; D005260:Female; D006347:Heart Sounds / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology*; D007223:Infant; D008297:Male; D011651:Pulmonary Artery / Q000502:physiology*; D019023:Stethoscopes / Q000706:statistics & numerical data; D055815:Young Adult
keywords: Auscultation; Fast Fourier transform; Machine learning; Phonocardiography; Stethoscope