Fetal Right Heart Strain in Systemic Right Ventricles and Impact on Post-surgical Outcomes

Patients with hypoplastic left heart syndrome (HLHS) and its variants rely on the right ventricle (RV) to provide cardiac output. Diminished RV systolic function has been associated with poor clinical outcomes in this population. Echocardiographic strain has emerged as a useful method to quantify RV deformation. We aimed to describe fetal strain in the systemic RV and further investigate if there was any correlation with clinical outcomes. We conducted a retrospective, single center study evaluating strain in fetuses with systemic RV. We measured fetal RV global longitudinal strain (GLS) and segmental strain using Tomtec 2D speckle tracking software and compared these findings to controls. Fifty patients with systemic RV were included in the study group with controls matched one to one for each echocardiogram. Ten patients died after first-stage palliation. GLS was reproducible, with interobserver ICC 0.82. There was no statistically significant difference in GLS among different HLHS subtypes. Abnormal GLS did not correlate with worse clinical outcomes. GLS in systemic RVs in the 2nd and 3rd trimester did not vary significantly throughout gestation and did not correlate with clinical outcomes. Risk factors associated with poor outcome were mainly postnatal. Multi-centered studies are needed to determine if these findings hold true in a larger sample size.