Our principal aim was to describe functional changes in dilated left atrium (LA) of children by using new applications of LA strain. We studied 66 patients (age range 0.2-22 years) consisting of 33 with LA enlargement. We utilized speckle-tracking imaging for assessment LA longitudinal strain (S) and longitudinal displacement (D). S-D loops were generated by plotting S and D data along Y and X axes, respectively. We also measured noninvasive LA stiffness index, [Formula: see text] (%-1). Peak S in controls was 51.16 ± 19.45% versus 23.16 ± 13.66% in dilated LA (p < 0.0001). S-D loops in dilated LA group were significantly smaller compared to controls (2.62 ± 2.88 units vs. 5.24 ± 4.00 units, p < 0.01). Noninvasive LA stiffness index was higher in dilated LA group (0.77 ± 0.63%-1 vs. 0.17 ± 0.07%-1, p < 0.0001). A cut-off LA stiffness value of 0.25%-1 was found to maximize sensitivity and specificity (84.0% and 84.85%, respectively). Children with enlarged LA demonstrate decreased peak S, abnormal S-D loops and increased LA stiffness, providing a newer insight into LA function. Evaluation of LA mechanics may be applied in future as a surrogate for left ventricular filling parameters.
Keywords: Left atrial mechanics; Left atrial stiffness; Left atrial strain; Left atrium; Strain–displacement loop.