Abstract 11861: A Novel Clinical Method for Quantification of Myocardial Work and Stroke Work by Left Ventricular Pressure-Strain and Pressure-Volume Loop Area Constructed by 3-Dimensional Echocardiography.

Introduction: Left ventricular (LV) pressure-strain loop and pressure-volume loop area reflect myocardial work (MW) and stroke work (SW). However, clinical use of these indexes is limited by the need of invasive pressure measurement. A noninvasive method to obtain LV pressure-strain loop area was recently introduced. We sought to evaluate global MW and SW by LV pressure-strain and pressure-volume loop area by 3-dimensional speckle tracking echocardiography (3D-STE) in heart failure (HF) and compare those indexes with controls to elucidate the utility of the indexes. Methods: STE was performed and systolic blood pressure (SBP) was measured in 24 patients with HF and ejection fraction (EF) < 50% (age 73±6) and 36 controls (71±10). LV pressure was estimated using SBP, minimum diastolic pressure (mDP) and end-diastolic pressure (EDP) by utilizing the profile of an empiric, normalized reference curve which was adjusted according to the duration of LV isovolumic and ejection phases. The mDP and EDP were estimated as 5mmHg and as 12.3 - 10.1 x Log (left atrial active emptying function / minimum volume) as we reported. LV SW was obtained by LV pressure-volume loop area using the combination of pressure (SBP, mDP and EDP) and volume by 3D-STE. Results: LV pressure-volume loop was noninvasively obtained. LVEF and longitudinal strain in HF reduced compared to normal (LVEF; normal: 65±6 vs HF: 40±9*%, strain; -12±3 vs -8±3*%, *p<0.05 vs normal). LV end diastolic and systolic volume in HF increased compared to normal (84±24 vs 124±37* and 35±13 vs 78±34*ml). LV MW in HF reduced compared to normal (1790±412 vs 1045±423*mmHg%) and SW in HF tended to decrease (3946±1682 vs 3628±983mmHgml). MW had a good correlation with strain (r=0.60, p<0.01) and SW had a correlation with stroke volume (r=0.69, p<0.01). Conclusions: LV global MW and SW were noninvasively obtained by LV pressure-strain and volume area by 3D-STE. This novel noninvasive method may have a clinical interest and value to assess LV function. [ABSTRACT FROM AUTHOR]