Sequential changes of longitudinal and radial myocardial deformation indices in the healthy neonate heart.
BACKGROUND
Significant hemodynamic changes, including preload and afterload modifications, occur during the transition from the fetal to the neonatal environment. The ductus arteriosus closes, pulmonary vascular resistance decreases, and pulmonary blood flow increases. Strain rate (SR) and strain (epsilon) have been proposed as ultrasound indices for quantifying regional wall deformation. This study was designed to determine if these indices can detect variations in regional deformation between early and late neonatal periods.


METHODS
Data were obtained from 30 healthy neonates (15 male). The initial study was performed at a mean age of 20.1+/-14 hours (exam 1) and the second at 31.9+/-2.9 days (exam 2). Apical and parasternal views were used to quantify regional left ventricular (LV) and right ventricular (RV) longitudinal and radial SR and epsilon, and systolic, early, and late diastolic values were calculated from these curves. A paired-samples t test was performed comparing the two groups.


RESULTS
Compared with exam 1, LV radial deformation showed significant reductions in peak systolic epsilon in the basal and mid segments (51+/-15% vs 46+/-9%, P<.01). LV longitudinal deformation behaved similarly, showing significant peak systolic epsilon reductions in all measured segments. Systolic SR showed reductions only in the basal and apical segments of the lateral wall and in the mid portion of the inferior wall (-1.9+/-0.5 vs -1.7+/-0.3 s(-1) and -1.9+/-0.4 vs -1.7+/-0.2 s(-1), respectively, P=.03). RV longitudinal free and inferior wall systolic SR and epsilon values were significantly higher in exam 2.


CONCLUSIONS
LV peak systolic epsilon decreases in exam 2 were possibly due to afterload increase and preload decrease. The lower RV initial deformation indices could be attributed to increased afterload caused by physiologic pulmonary hypertension or immature RV contractile properties. SR seemed to be a more robust index than epsilon and less influenced by preload and afterload hemodynamic alteration.
Pena
José Luiz Barros
JL
Heart Institute (InCor) USP, São Paulo, Brazil. jlpena.bh@terra.com.br
da Silva
Marconi Gomes
MG
Alves
José Mariano Sales
JM
Salemi
Vera Maria Cury
VM
Mady
Charles
C
Baltabaeva
Aigul
A
Sutherland
George R
GR
D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007231:Infant, Newborn; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*