Reliability and feasibility of longitudinal AFI global and segmental strain compared with 2D left ventricular volumes and ejection fraction: intra- and inter-operator, test-retest, and inter-cycle reproducibility.

Abstract

Echocardiographic evaluation of 2D longitudinal peak systolic strain (LPSS) can detect initial impairment of left ventricular (LV) function in heart disease. Global LPSS (GLPSS) variability has been assessed in small groups and segmental LPSS has not been determined. We compared variability of GLPSS and segmental LPSS with that of 2D LV volumes and ejection fraction (EF) in patients with and without heart diseases. 2D speckle tracking analysis was performed on LV apical views using automated function imaging (AFI) software (GE Healthcare). Intra-operator, inter-cycle, and test-retest variability (bias and CR, coefficient of reproducibility; MPE, mean percent error; CV, coefficient of variation) was assessed for GLPSS, 18 segments of LPSS, and LV volumes and EF in 40 patients (720 segments), and inter-operator variability in 250 patients (4500 segments). Feasibility of segmental tracking was 93.1%. Variability of GLPSS increased from a minimum intra-operator CV = -2.6% to a maximum test-retest CV = -5.4% and was lower than that assessed for volumes and EF. Segmental intra-operator LPSS CV ranged from -5.6 to -14.7%, and test-retest from -8 to -22%, and was at worst similar to variability of end-systolic volume. In the 8.3% of segments with the highest variability, this was related to suboptimal imaging, minor changes in scan angulation, and insufficient ROI width. Overall, reproducibility of GLPSS is excellent and superior to that of 2D EF, whereas segmental LPSS reproducibility is good and similar to that of LV volumes. Both are suitable for diagnosis and follow-up of LV global and regional systolic function.