Left ventricular rotational mechanics in infants with hypoxic ischemic encephalopathy and preterm infants at 36 weeks postmenstrual age: A comparison with healthy term controls

Abstract

Infants with HIE have reduced rotational mechanics. Preterm infants at 36 weeks PMA have comparable measurements of twist to term infants. This is achieved by predominant basal rather than apical rotation. Infants with CLD have increased apical rotation.

Left ventricular ejection fraction using manual and semi‐automated biplane method of discs in very preterm infants

“…The LVEF remained stable, ranging between 46% and 66% during the study period and the semi‐automated method produced comparable LVEF with less measurement variability. The LVEF in the early post‐transitional period and at 36 weeks PMA reported in this study is similar to the LVEF in previous reports 22–25 …”

“…This study reports longitudinal biplane LVEF in very preterm infants during the neonatal intensive care period and feasibility of speckle tracking software for semi‐automatic determination of LVEF. In spite of immaturity of myocardial architecture, the biplane LVEF in preterm infants observed in this study was similar to LVEF previously reported in term infants, which indicates that the efficiency of the LV pump to handle the physiologic preload is well established in preterm infants during the early postnatal period 14,22–25 . The LVEF remained stable, ranging between 46% and 66% during the study period and the semi‐automated method produced comparable LVEF with less measurement variability.…”

“…In children, LVEF >55% is considered normal and a LVEF persistently below 40% is associated with a higher risk of mortality 34 . Although the threshold of LVEF in neonates for diagnosis of cardiac dysfunction has not been reported in recent guidelines, data from this and other studies would suggest that a LVEF >50% can be considered normal 5,14,23,25 . The immaturity of myocardial architecture and relatively low compliance, low shortening velocity and restricted ability of cardiac myofibrils to generate contractile force reported in experimental studies suggest that both cardiac systolic and diastolic mechanisms are not fully established in preterm infants 1 .…”

“…Being a fractional difference between maximum and minimum LV volumes during one cardiac cycle, LVEF is an indicator of the global strength and efficiency of LV pump in handling LV preload. Furthermore, data show that the LVEF stays relatively unchanged with advancing age, making its use in clinical practice and comparison between groups of infants convenient 14,22–25 . In children, the LVEF is commonly used for detection of heart failure, grading severity, guiding treatment, and prognosticating of cardiac failure 7,34 .…”

Do you see what I see? Viewing the world through the prism of colour blindness

“…There are a number of factors related to calcium delivery and use in the neonatal myocardium which impair contractile ability. The sarcoplasmic reticulum (SR), which senses and triggers calcium-induced calcium release (CICR) in order to potentiate contraction is immature, as well as the T-tubules which invaginate into the myocyte to bring L-type calcium channels into closer contact with the SR ryanodine receptors (Ikonnikov and Yelle, 2013;Breatnach et al, 2017). There is evidence that these factors, alongside altered calcium handling, lead to generation of less force during contraction (Wiegerinck et al, 2009).…”