title: Normal ranges and physiological changes of midwall fractional shortening in healthy korean population.
abstract: OBJECTIVE
  Left ventricular (LV) midwall fractional shortening (FSmw) reflects systolic function more accurately than LV endocardial fractional shortening (eFS) in patients with increased LV wall thickness. Although the normal reference ranges of LV-FSmw have been suggested in Western population studies, its reference values and age-related physiological changes in Eastern populations remain unknown.
  
  
  METHODS
  Conventional echocardiographic parameters, LV-FSmw, and stress-corrected LV-FSmw were assessed in 160 healthy and clinically normal subjects with a mean age of 45 (range, 11-72 years; 104 males, 56 women), all of whom were confirmed to be free of disease, based on laboratory investigations, clinical and physical examination findings and computed tomographic coronary angiographic examinations.
  
  
  RESULTS
  LV-FSmw was higher in women compared to men. However, the differences were without statistical significance (18.2±1.5% for male gender and 19.4±2.5% for female gender, p=0.07). In contrast to LV-eFS that progressively increased with age (p=0.001), LV-FSmw and stress-corrected LV-FSmw was not influenced by changes in age (p=0.88 and 0.29, respectively). The results remained unchanged when analyses were performed adjusting for gender.
  
  
  CONCLUSIONS
  The results of this study provide normal reference values for LV-FSmw and stress-corrected LV-FSmw and their natural physiological changes with advancing age. These measures can be used as reference standards for research on LV systolic function in the setting of pressure or volume overload.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyungil
authors.initials: K
authors.lastname: Park
authors.forename: Sung-A
authors.initials: SA
authors.lastname: Chang
authors.forename: Hyung-Kwan
authors.initials: HK
authors.lastname: Kim
authors.forename: Hyo-Eun
authors.initials: HE
authors.lastname: Park
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Na
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Dae-Won
authors.initials: DW
authors.lastname: Sohn
authors.forename: Byung-Hee
authors.initials: BH
authors.lastname: Oh
authors.forename: Young-Bae
authors.initials: YB
authors.lastname: Park