Patterns of Segmental Longitudinal, Circumferential and Radial Strain of the Left Ventricle in Extremely Premature Infants in the Early Neonatal Period

Extremely premature newborns are predisposed to cardiovascular complications due to a number of factors, including myocardial immaturity, hemodynamic changes, and iatrogenic effects. There are few studies on myocardial strain in extremely premature infants during the early neonatal period. The objective of study was to assess the left ventricular (LV) segmental strain in ex-tremely premature newborns during the early neonatal period by employing speck-le-tracking echocardiography (STE). This prospective study examined 65 newborns with no signs of hemodynamic impair-ment during the first 72 hours of life.The cohort had a range of birth weights (600-1500 grams) and gestational ages (24-35 weeks). The peak strain in 18 LV segments during systole (peak S and time to peak S), throughout the cardiac cycle (peak G and time to peak G), and during early systolic prestretch (peak P and time to peak P) were assessed in the longitudinal, circumferen-tial, and radial directions. We obtained percentile tables of segmental strain characteristics in the longitudinal, circumferential, and radial directions. No dependence of segmental strain on birth weight, gestational age, or arterial duct closure was found. A positive gradient of lon-gitudinal strain magnitude was observed from the base to the apex. The greatest cir-cumferential and radial strain were observed in LV septum. This study marks the first complete investigation of longitudinal, circumferential, and radial LV strain using STE in extremely premature infants with no signs of hemody-namic disturbances during the first 72 hours of life. Reference values for segmental strain were established.