Decreased right ventricular longitudinal strain in children with hypoplastic left heart syndrome during staged repair and follow-up: does it have implications in clinically stable patients?

The principal aim of this study was to evaluate changes in systolic function in the single right ventricle (SRV), during progression of the same patient through the three stages of surgical repair for hypoplastic left heart syndrome and during a 5-year follow-up. We hypothesize that, SRV global longitudinal strain (GLS) will be low during 3 stages of repair even in stable patients. We retrospectively evaluated 140 echocardiograms in 20 patients with HLHS (ages 0-11.3 years), before and after 3 stages of surgical palliation. Five-year follow-up data were available in all 20 patients. Controls with structurally normal hearts and in the same age group were used for comparison. We utilized speckle-tracking imaging for assessment of SRV segmental and global longitudinal and circumferential strains, from previously acquired 4-chamber and mid-cavity short-axis views prior to and within 1-3 months of each surgical stage. Longitudinal strain (LS) remained low through all 3 stages of repair and during follow-up. The pre-Fontan stage demonstrated significant interstage improvement compared to the post-Glenn stage despite similar volume status. Global LS was (- 15.6 ± 4.5% after Fontan surgery and remained similar (- 15.32 ± 3.2%) 5 years later. The SRV also showed increased dominance of circumferential strain compared to the normal RV, where the longitudinal deformation was dominant. In SRV, longitudinal strain may be a useful clinical index for evaluating both segmental and global function in an objective manner. Due to lack of significant clinical deterioration over a 10-year period, we speculate that a "lower-than-normal" longitudinal strain may be used as an objective measure of SRV function in clinically stable patients, particularly after the Fontan operation. Compensatory mechanisms where the longitudinal pattern of contraction switches to a more circumferential pattern, may play a role in asymptomatic patients with HLHS.