Doppler tissue, strain, and strain rate imaging in pediatric patients with Alström syndrome: are there regional functional abnormalities?

Objective: We sought to determine the potential additive usefulness of Doppler tissue imaging (DTI), strain (epsilon), and epsilon rate (SR) imaging in assessing systolic function in pediatric patients with Alström syndrome.
Methods: We conducted a case-control study at a pediatric hospital with 5 patients (age 5-18 years) with Alström syndrome living in Atlantic Canada and 21 age- and sex-matched healthy control subjects. Standard echocardiographic examination was followed by DTI of the interventricular septum (IVS) and left ventricle (LV) lateral wall, longitudinal epsilon, and SR at the basal, mid, and apical segments of the LV lateral, inferior, and anterior walls, and the IVS. We also imaged radial epsilon and SR of the interventricular posterior wall.
Results: For patients versus control subjects, conventional ejection fraction (0.65 vs 0.72) and fractional shortening (0.30 vs 0.35) did not distinguish between groups. DTI-derived s-waves consistently demonstrated significant differences in systolic function (LV lateral wall 0.073 vs 0.100; IVS 0.064 vs 0.080; LV anterior wall 0.066 vs 0.096; LV inferior wall 0.069 vs 0.092 [P < .05 in all positions]). Epsilon differences were observed in the movement of the mid-LV lateral (-10.4 vs -15.2, P = .035), basal LV anterior wall (-16.3 vs -22.9, P = .004), and the apical IVS (-6.3 vs -13.8, P = .015). SR at the midposition of the LV lateral wall (-0.7 vs -1.4, P = .000) also differed between the groups. Substantial diastolic function differences were also observed between patients and control subjects.
Conclusion: Detection of systolic and diastolic function abnormalities in patients with Alström syndrome can potentially be enhanced by the use of DTI, epsilon, and SR imaging.