Systolic thickening increases from subepicardium to subendocardium

Abstract

<it>Study objective</it> – The aim was to determine the relation between systolic function and depth below the epicardial surface, using pulsed Doppler crystals. <it>Design</it> – Systolic excursion in mm was measured at multiple depths below the epicardial surface. Measurements were made during control conditions. <it>Subjects</it> – Thirty four anaesthetised mongrel dogs were studied. <it>Measurements and main results</it> – 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). <it>Conclusions</it> – These data support the prediction from geometric models that systolic excursion increases in a non-linear fashion from subepicardium to subendocardium.