Abstract 20435: Myocardial Mechanics of the Systemic Right Ventricle in Hypoplastic Left Heart Syndrome Through the Perinatal Transition
Background: Rapid changes occur in myocardial loading during the transition from the fetal to postnatal circulation. In healthy neonates, the LV output almost doubles within hours of delivery but decreases to levels slightly higher than the fetal LV output within the first few days. In contrast, we have found in Hypoplastic left heart syndrome (HLHS) the combined cardiac output (CO) is initially similar to that of the late gestation fetus with a gradual but progressive increase occurring within the first 3-5 days. We sought to define the functional changes of the systemic right ventricle (RV) during the perinatal transition in the neonate with HLHS.
Methods: We prospectively recruited 11 pregnancies with fetal HLHS. Echocardiograms were performed in late gestation and at 4 -12, 20-24, 44-48 hours (hrs) and 3-5 days after birth. Hemodynamics including stroke volume (SV), heart rate (HR), CO, blood pressure (BP), and RV size and fractional area change (FAC) were measured. High frame rate images were used for offline strain and strain rate (SR) analysis using speckle tracking. ANOVA with repeated measures and paired t-test for parameters and Pearson’s correlations were used.
Results: In the first 24 hrs, CO increased (p=0.03) which was accompanied by an increase in RV longitudinal strain (p=0.03). From 24 hrs to 5 days, although CO and SV continued to increase (p<0.001 for both) along with progressive increase in RV end diastolic size (p<0.002), no further increase in longitudinal strain and SR was observed. There was no change in HR, systolic BP or RV FAC between intervals. Longitudinal strain and SR correlated with CO (r=-0.44; p=0.007 & r=-0.60; p=0.0001 respectively) and SV (r=-0.46; p=0.004 & r=-0.55; p=0.0006 respectively). Longitudinal SR also correlated with RV FAC (r=-0.40; p=0.01) and RVEDV (r =0.37; p=0.02).
Conclusion: The RV in neonatal HLHS appears to compensate by initially increasing its longitudinal deformation in the first 24 hrs to meet the postnatal circulatory demands. Thereafter, subsequent increase in CO relies on increasing SV through progressive increase in ventricular preload. Further studies using deformation imaging are needed to explore RV adaptation in early transition in HLHS neonates and its implication on management and outcome.
Author Disclosures: S.S. Dhillon: None. A. Hirose: None. N.S. Khoo: None. L. Mills: None. T. Colen: None. W. Savard: None. P. Cheung: None. L. Hornberger: None.
- © 2014 by American Heart Association, Inc.