Do left atrial strain and strain rate reflect intrinsic atrial function, or are they determined by left ventricular function?

Background: Left atrial (LA) strain (S) and strain rate (SR) are reported as measures of intrinsic function. Aim: Since the LA and left ventricle (LV) are connected through the mitral annulus, we investigated: (1) if deformation indices in the LA are mostly predicted by deformation of the LV; (2) if timings of S and SR events are similar in both the LA and LV; and (3) if alteration of S and SR in patients with primarily LV dysfunction would be similar in the LA and LV. Methods: We retrospectively assessed 50 asymptomatic women (Group 1) and 20 patients with recent (< 96 h) acute pulmonary oedema (10 women) (Group 2). Using speckle tracking, the amplitude and timings of S and SR were averaged from three apical views, for one cardiac cycle, starting from the P-wave. Results: In Group 1, all deformation indices were higher in the LA compared with the LV (p < 0.001 for all). In Group 2, S and SR during LA contraction were higher in the LA vs. LV (p < 0.05 for both), but all other deformation indices were not different in the LA vs. LV. All timings of S and SR occurred simultaneously in LA and LV in both groups, except S during LA contraction in Group 1, which occurred slightly earlier in LA than in LV. By multiple regression analysis, the most important predictors of LA deformation indices were the corresponding LV deformation indices, especially in patients with LV dysfunction (Group 1: r = 0.35–0.52; Group 2: r = 0.76–0.85; p < 0.05 by Fisher r-to-z transform). Conclusions: LA deformation strongly reflects LV deformation both in asymptomatic subjects and in patients with LV dysfunction. With the possible exception of LA contraction in asymptomatic individuals, discriminating intrinsic LA function from LV influence is difficult using deformation analysis