title: Normal age-related changes in left ventricular function: Role of afterload and subendocardial dysfunction.
abstract: BACKGROUND
  In normal ageing, both vascular and ventricular properties change, and how these affect left ventricular function is not clear.
  
  
  METHODS
  96 subjects (ages 20-79) without cardiovascular disease underwent cardiac magnetic resonance (MR) imaging for measurement of global function, diastolic function (E/A ratio), MR tagging for measurement of torsion to shortening ratio (TSR, ratio of epicardial torsion to endocardial circumferential shortening, with increase in TSR suggesting subendocardial dysfunction relative to the subepicardium), and phase contrast MR imaging measurement of central aortic pulse wave velocity (PWV). The Vicorder device was used to measure carotid to femoral PWV.
  
  
  RESULTS
  Univariate correlations established that the 4 principal age-related changes in the left ventricular function were: 1) diastolic function: E/A ratio (r: -0.61, p<0.00001); 2) global systolic function: cardiac output (r: -0.49, p<0.00001), 3) structure: end-diastolic volume index (r: -0.39, p<0.0001), and 4) systolic strains: TSR (r: 0.49, p<0.0001). Multiple linear regression analysis showed that age was the dominant factor in predicting changes in cardiac output and E/A ratio (both p<0.01). Increased TSR was significantly related to reduced cardiac output and end-diastolic volume index (p<0.05 and p<0.01 respectively). Measures of vascular stiffness were not significantly related to any of these variables, but increased effective arterial elastance (afterload) was significantly related to reduced E/A ratio (p<0.05).
  
  
  CONCLUSIONS
  In this group of normal ageing subjects, afterload but not vascular stiffness is significantly related to diastolic dysfunction. Increased TSR, suggesting relative subendocardial dysfunction, has a significant role in reductions of cardiac output and end-diastolic volume index.
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Jehill D
authors.initials: JD
authors.lastname: Parikh
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Kieren G
authors.initials: KG
authors.lastname: Hollingsworth
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Dorothy
authors.initials: D
authors.lastname: Wallace
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Blamire
authors.affiliation: Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Centre for In Vivo Imaging, Newcastle University, Newcastle upon Tyne, United Kingdom; Dept. of Cardiology, Freeman Hospital, Newcastle upon Tyne, United Kingdom. Electronic address: guy.macgowan@nuth.nhs.uk.
authors.forename: Guy A
authors.initials: GA
authors.lastname: MacGowan
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000473:pathology / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000639:trends; D008297:Male; D008875:Middle Aged; D006113:United Kingdom / Q000453:epidemiology; D059289:Vascular Stiffness / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology; D016277:Ventricular Function, Left / Q000502:physiology*; D055815:Young Adult
keywords: Ageing; Magnetic resonance imaging; Mechanics