title: Systolic thickening increases from subepicardium to subendocardium.
abstract: OBJECTIVE
  The aim was to determine the relation between systolic function and depth below the epicardial surface, using pulsed Doppler crystals.
  
  
  METHODS
  Systolic excursion in mm was measured at multiple depths below the epicardial surface. Measurements were made during control conditions.
  
  
  METHODS
  Thirty four anaesthetised mongrel dogs were studied.
  
  
  RESULTS
  A total of 333 measurements of systolic excursion were made during control conditions at 1 to 3 crystal sites per dog. Two models were constructed; the model which assumed a quadratic relation between depth (d) and systolic excursion (EX) (EX = 0.498 + 0.176d + 0.006d2) fit the data better than did a model which assumed a linear relation (EX = -0.0716 + 0.254d).
  
  
  CONCLUSIONS
  These data support the prediction from geometric models that systolic excursion increases in a non-linear fashion from subepicardium to subendocardium.
authors.affiliation: Division of Cardiology, Milton S Hershey Medical Center, Pennsylvania State University, Hershey 17033.
authors.forename: J A
authors.initials: JA
authors.lastname: Gascho
authors.forename: G L
authors.initials: GL
authors.lastname: Copenhaver
authors.forename: D F
authors.initials: DF
authors.lastname: Heitjan
mesh_terms: D000818:Animals; D001794:Blood Pressure; D004285:Dogs; D015150:Echocardiography, Doppler; D004699:Endocardium / Q000502:physiology; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D007091:Image Processing, Computer-Assisted; D009200:Myocardial Contraction; D010496:Pericardium / Q000502:physiology; D013599:Systole