BACKGROUND: Although left ventricular end-systolic elastance (E(es)) has often been used as an index of contractility, technical difficulties in measuring volume and in changing loading conditions have made its clinical application somewhat limited. By approximating the time-varying elastance curve by 2 linear functions (isovolumic contraction phase and ejection phase) and estimating the slope ratio of these, we developed a method to estimate E(es) on a single-beat basis from pressure values, systolic time intervals, and stroke volume. METHODS AND RESULTS: In 11 anesthetized dogs, we compared single-beat E(es) with that obtained with caval occlusion. Although the decrease (but not the increase) in contractility (5.3 to 11.4 mm Hg/mL) and the change in loading conditions (3.7 to 34.0 mm Hg/mL) over wide ranges significantly altered the slope ratio, the estimation of E(es) was reasonably accurate (y=0.97 x 0.46, r=0. 929, SEE=2.1 mm Hg/mL). CONCLUSIONS: E(es) can be estimated on a single-beat basis from easily obtainable variables by approximating the time-varying elastance curve by a bilinear function.
BACKGROUND: Although left ventricular end-systolic elastance (E(es)) has often been used as an index of contractility, technical difficulties in measuring volume and in changing loading conditions have made its clinical application somewhat limited. By approximating the time-varying elastance curve by 2 linear functions (isovolumic contraction phase and ejection phase) and estimating the slope ratio of these, we developed a method to estimate E(es) on a single-beat basis from pressure values, systolic time intervals, and stroke volume. METHODS AND RESULTS: In 11 anesthetized dogs, we compared single-beat E(es) with that obtained with caval occlusion. Although the decrease (but not the increase) in contractility (5.3 to 11.4 mm Hg/mL) and the change in loading conditions (3.7 to 34.0 mm Hg/mL) over wide ranges significantly altered the slope ratio, the estimation of E(es) was reasonably accurate (y=0.97 x 0.46, r=0. 929, SEE=2.1 mm Hg/mL). CONCLUSIONS: E(es) can be estimated on a single-beat basis from easily obtainable variables by approximating the time-varying elastance curve by a bilinear function.
Authors: Naomi Wo; Vijay Rajagopal; Michael M H Cheung; Joseph J Smolich; Jonathan P Mynard Journal: Heart Vessels Date: 2018-11-14 Impact factor: 2.037
Authors: David Steflik; Ryan J Butts; George H Baker; Varsha Bandisode; Andrew Savage; Andrew M Atz; Shahryar M Chowdhury Journal: Echocardiography Date: 2017-07-28 Impact factor: 1.724
Authors: David Stevenson; James Revie; J Geoffrey Chase; Christopher E Hann; Geoffrey M Shaw; Bernard Lambermont; Alexandre Ghuysen; Philippe Kolh; Thomas Desaive Journal: Biomed Eng Online Date: 2012-06-15 Impact factor: 2.819