Fetal and Neonatal Echocardiographic Analysis of Biomechanical Alterations for the Hypoplastic Left Heart

Background Hypoplastic left heart syndrome (HLHS) presents diagnostic and prognostic challenges while progressing toward heart failure (HF). Understanding the fetal and neonatal HLHS biomechanics, including novel hydrodynamic parameters, could help better planning of the long-term management of HLHS patients. Objectives Compare fetal and neonatal HLHS cardiac biomechanics against normal subjects using echocardiography. Methods We performed a retrospective study of 10 HLHS patients with echocardiograms at 33-weeks gestation and at the first week post-birth and 12 age-matched controls. We used in-house developed analysis algorithms to quantify ventricular biomechanics from four-chamber B-mode and color Doppler scans. Cardiac morphology, hemodynamics, tissue motion, deformation, and flow parameters were measured. Results Tissue motion, deformation, and index measurements did not reliably capture biomechanical changes. Stroke volume and cardiac output were nearly twice as large for the HLHS right ventricle (RV) compared to the control RV and left ventricle (LV) due to RV enlargement. The enlarged RV exhibited disordered flow with higher energy loss (EL) compared to prenatal control LV and postnatal control RV and LV. Furthermore, the enlarged RV demonstrated elevated vortex strength (VS) compared to both the control RV and LV, prenatally and postnatally. The HLHS RV showed reduced relaxation with increased early filling velocity ( E ) compared prenatally to the LV and postnatally to the control RV and LV. Furthermore, increased recovery pressure (Δ P ) was observed between the HLHS RV and control RV and LV, prenatally and postnatally. Conclusions The novel hydrodynamic parameters more reliably capture the HLHS alterations in contrast to traditional parameters. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This project was supported by the Indiana Clinical and Translational Sciences Institute and funded, in part, by Grant Number UL1TR002529 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award and, in part, by Grant Number 1R21HD109490 from the National Institues of Health, National Institute of Child Health & Human Development. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. No industry partnerships collaborated on or funded this work ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Institutional Review Board for Human Studies for Purdue and Indiana universities and Children's National Hospital approved the study. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data will be made available upon request. * AV : Atrioventricular ALAX : Apical long axis CFI : color flow imaging CO : Cardiac output EL : Energy loss HLHS : Hypoplastic Left Heart Syndrome VS : Vortex strength SV : Stroke volume Δ P : Pressure difference IVPD : Intraventricular pressure difference