Comprehensive assessment of left ventricular myocardial function by two-dimensional speckle-tracking echocardiography

Abstract

BackgroundLeft ventricular ejection fraction (LVEF) results from the combined action of longitudinal and circumferential contraction, radial thickening, and basal and apical rotation. The study of these parameters together may lead to an accurate assessment of the cardiac function.MethodsNinety healthy volunteers, categorized by gender and age (≤ 55 and > 55 years), were evaluated using two-dimensional speckle tracking echocardiography. Transversal views of the left ventricle (LV) were obtained to calculate circumferential strain and left ventricular twist, while three apical views were obtained to determine longitudinal strain (LS) and mitral annular plane systolic excursion (MAPSE). We established the integral myocardial function of the LV according to: 1. The Combined Deformation Parameter (CDP), which includes Deformation Product (DP) - Twist x LS (° x %) - and Deformation Index (DefI) -Twist / LS (° / %)-; and 2. the Torsion Index (TorI): Twist / MAPSE (° / cm).ResultsThe mean age of our patients was 50.3 ± 11.1 years. CDP did not vary with gender or age. The average DP was − 432 ± 172 ° x %, and the average DefI was − 0.96 ± 0.36 ° / %. DP provides information about myocardial function (normal, pseudonormal, depressed), and the DefI quotient indicates which component (s) is/are affected in cases of abnormality. TorI was higher in volunteers over 55 years (16.5 ± 15.2 vs 13.1 ± 5.0 °/cm, p = 0.003), but did not vary with gender.ConclusionsThe proposed parameters integrate values of twisting and longitudinal shortening. They allow a complete physiological assessment of cardiac systolic function, and could be used for the early detection and characterization of its alteration.

Two-dimensional Echocardiographic Assessment of Myocardial Strain: Important Echocardiographic Parameter Readily Useful in Clinical Field

“…A proposed peak GLS value of 20% was proposed as a reference value for a healthy person 16)Table 1 summarizes the normal reference values for the LV 27)28)29)30)31). In this table, negative values mean systolic shortening, and lower values mean better systolic function.…”

Cardiac Helical Function

“…The difference in the duration of mean systolic strain between the systolic and postsystolic phase in the echocardiographic work of Mora Llabata et al is 88 ± 7.1 ms, a value analogous to those found in our research in relation to the duration of the ascending segment activation in the suction phase. (23,24) We have measured the left intraventricular pressure curve in patients who underwent cardiac resynchronization therapy in order to show the improvement at the level of the suction mechanism in the diastolic isovolumic phase.…”

“…New parameters, possibly more adjusted to the current knowledge of physiology described, have been incorporated into our recent experience, including twist movements and the longitudinal shortening motions that are simultaneously developed during ventricular systole. (24) These are: a) the torsion index (twist/mitral annulus translational motion); and b) strain index (twist/left ventricular global longitudinal strain). Both parameters translate the active motions that are produced during systole "squeezing" the left ventricle, with a value of 13.1 ± 4 °/cm for the torsion index and 0.96 ± 0.36°/% for the strain index in the healthy population studied.…”

Influence of Ventricular Wringing on the Preservation of Left Ventricular Ejection Fraction in Cardiac Amyloidosis

“…Next, we evaluated the deformation index (DefI) (calculated as twist/LS), a parameter of LV wringing that integrates both twist and longitudinal shortening, 25 actions that are simultaneously produced during contraction of the left ventricle. LS is expressed in negative values in such a way that more negative DefI values represent a greater level of wringing.…”

“…The distinctive helical structure of obliquely oriented myocardial fibers 19,20 results in systolic rotation of the base and apex of the left ventricle in opposite directions around its longitudinal axis and the simultaneous shortening of the left ventricle as the base is displaced toward the apex, [19][20][21][22][23][24] all of which results in ventricular wringing. 25 The combination of these events determines ventricular radial thickening and LVEF.…”