Background: Left 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.
Methods: Ninety 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).
Results: The 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.
Conclusions: The 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.
Keywords: Deformation imaging; Myocardial strain; Speckle tracking; Ventricular function; Ventricular torsion.