title: Longitudinal Assessment of Left and Right Myocardial Function in Preterm Infants Using Strain and Strain Rate Imaging.
abstract: BACKGROUND
  There is a paucity of longitudinal data on left ventricular (LV) and right ventricular (RV) function in preterm infants of less than 29 weeks' gestation.
  
  
  OBJECTIVE
  The aim of this study was to describe changes in tissue Doppler-derived basal longitudinal strain (BLS) and systolic (SRs), early (SRe) and late (SRa) diastolic strain rates in extremely premature infants from birth to 36 weeks postmenstrual age (PMA).
  
  
  METHODS
  Echocardiographic assessments were carried out on days 1, 2, 5-7 and at 36 weeks PMA. We assessed the following associations: correlation with systemic vascular resistance (SVR) on day 1, influence of a patent ductus arteriosus (PDA) during days 5-7, and the effect of chronic lung disease (CLD).
  
  
  RESULTS
  In total, 105 infants with a median gestation of 27.1 weeks (IQR 26.0-28.1) and a birthweight of 965 g (IQR 785-1,153) were included. There was an increase in most of the measurements across the four time points. On day 1, there was a weak negative correlation between SVR and LV BLS (r = -0.3, p = 0.01), SVR and septal BLS (r = -0.4, p < 0.001) and SVR and LV SRe (r = -0.4, p = 0.005). On days 5-7, infants with a PDA >1.5 mm had higher LV BLS [-13.0 (2.4) vs. -11.9 (1.9)%, p = 0.03]. At 36 weeks, infants with CLD (n = 28/47) had lower RV BLS [-26.4 (5.0) vs. -30.7 (5.5)%, p = 0.01] and lower RV SRa [4.2 (1.3) vs. 5.3 (1.9) s-1, p = 0.04].
  
  
  CONCLUSIONS
  Myocardial function undergoes important longitudinal changes in preterm infants. Left heart strain measurements appear to be weakly influenced by changes in preload and afterload. CLD appears to leave a negative impact on RV function.
authors.affiliation: Department of Neonatology, The Rotunda Hospital, Dublin, Ireland.
authors.forename: Adam T
authors.initials: AT
authors.lastname: James
authors.forename: J D
authors.initials: JD
authors.lastname: Corcoran
authors.forename: Colm R
authors.initials: CR
authors.lastname: Breatnach
authors.forename: Orla
authors.initials: O
authors.lastname: Franklin
authors.forename: Luc
authors.initials: L
authors.lastname: Mertens
authors.forename: Afif
authors.initials: A
authors.lastname: El-Khuffash
mesh_terms: D001724:Birth Weight; D003971:Diastole; D004374:Ductus Arteriosus, Patent / Q000503:physiopathology*; D015150:Echocardiography, Doppler; D005260:Female; D005865:Gestational Age; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D007055:Iceland; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D016014:Linear Models; D008171:Lung Diseases / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*; D016278:Ventricular Function, Right