title: M-mode echocardiographic values in a cohort of young healthy individuals.
abstract: OBJECTIVE
  To determine normal M-mode values in healthy young adults and to evaluate whether these values differ among those in whom echocardiography was performed routinely and those in whom echocardiography was performed based on clinical grounds.
  
  
  METHODS
  A cross-sectional study evaluating a large cohort of young academy applicants of the Israeli air force in the years 1994-2010. Studies were divided into those performed routinely and those performed because of abnormal ECG or physical examination findings. Echocardiographic variables were compared between the two groups and values are expressed as mean ± SD.
  
  
  RESULTS
  Echocardiography was performed routinely in 3525 applicants (age 18.5 ± 1.0 years) and following a clinical referral in 3517 applicants (age 18.2 ± 0.9 years). Those in whom echocardiography was performed routinely had slightly higher left ventricular end-systolic diameter (31.2 ± 3.3  vs. 30.7 ± 3.4 mm; P < 0.0001) and aortic root diameter (28.5 ± 2.1 vs. 27.9 ± 2.2 mm; P < 0.0001), and slightly lower left ventricular mass index (108.8 ± 15.8  vs. 109.9 ± 16.5 g/m; P = 0.005). No differences were noted between the two groups in left atrial diameter, left ventricular end-diastolic volume, posterior wall thickness and interventricular septum thickness.
  
  
  CONCLUSIONS
  Certain M-mode characteristics may differ (although to a slight degree) in young healthy individuals with electrocardiographic and physical findings compared with those with normal physical examination and electrocardiography.
authors.affiliation: aThe Israeli Air Force Aero Medical Center, Tel Hashomer bDepartment of Internal Medicine E, Rabin Medical Center, Beilinson Campus Affiliated to Tel Aviv University Sackler Medical School, Petah Tikva cUnit of Cardiovascular Epidemiology, The Gertner Institute for Epidemiology and Health Policy Research, Tel Hashomer dSackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Alon
authors.initials: A
authors.lastname: Grossman
authors.forename: Michal
authors.initials: M
authors.lastname: Benderly
authors.forename: Alex
authors.initials: A
authors.lastname: Prokupetz
authors.forename: Barak
authors.initials: B
authors.lastname: Gordon
authors.forename: Ofra
authors.initials: O
authors.lastname: Kalter-Leibovici
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004452:Echocardiography; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D012016:Reference Values; D055815:Young Adult