Abstract 17421: Vector Flow Mapping Quantification of Left Ventricular Energy Loss Occurring in Normal Subjects
Introduction: Vector flow mapping (VFM) can uniquely quantify left ventricular (LV) flow dynamics non-invasively. Energy loss produced by turbulent flow has promise to characterize cardiovascular diseases, but the degree of energy loss occurring in normal subjects is unknown.
Hypothesis: The aim of this study was to use VFM to quantify the degree of LV energy loss that occurs naturally in normal subjects and relate it to LV size and hemodynamics.
Methods: We studied 33 healthy subjects (Age 33±6.4, female 33%) by VFM and speckle tracking echo methods (PROSOUND F75 Premier CV, Hitachi Corp.). Energy loss (EL) was calculated from color Doppler apical long axis views. We tracked VFM for LV EL normalizing the time phase by a novel dual Doppler method, simultaneously recording LV inflow and outflow velocities. We the determined the association of EL with LV morphologic and hemodynamic parameters.
Results: VFM and speckle tracking were feasible in all subjects. LV EL demonstrated three peaks in one cardiac cycle: mid-systole, early-diastole and late-diastole. EL in mid-systole and late diastole were 7.19±3.45*10-3 J/m/s, 14.9±11.6*10-3 J/m/s and 3.23±1.73*10-3 J/m/s. Mid-systolic EL was positively correlated with body surface area-indexed LV end-diastolic volume (LVEDVI) and LV end-systolic volume (LVESVI) (r=0.508, p=0.002, and r=0.472, p=0.006). Early-diastolic EL was positively correlated with LVEDVI and LVESVI (r=0.531, p=0.003, and r=0.486, p=0.004). Early-diastolic EL was also positively correlated with max velocity of transmitral flow in early diastole (E wave) (r=0.572, p<0.001). RR interval indexed time to peak of Early-diastolic EL observed significant agreement with time to peak of E wave (r=0.808, p<0.001).
Conclusions: VFM assessment of energy loss is a novel means to quantify LV flow dynamics non-invasively. Energy loss in normal subjects relates to LV size and transmitral flow and has promise to characterize cardiovascular diseases.
Author Disclosures: M. Sugahara: None. Z. Qi: None. T. Koopsen: None. M.D. Simon: None. J. Gorcsan: Research Grant; Significant; BIotronik, GE, Medtronic, St. Jude Medical, Toshiba, Hitachi.
- © 2016 by American Heart Association, Inc.