title: M-mode echocardiographic evaluation of fetal and infant hearts: longitudinal follow-up study from intrauterine life to year one.
abstract: OBJECTIVE
  Our purpose was to evaluate cardiac variables, including right and left end-diastolic and end-systolic dimensions by use of M-mode echocardiography during fetal, neonatal (transitional), and infancy periods to understand hemodynamic adaptation during these periods.
  
  
  METHODS
  Fifty-three fetuses were enrolled in this study. Echocardiography evaluations were started as early as the sixteenth week of gestation and were repeated every 4 to 6 weeks until term, on postnatal days 1 and 2, and at 6 weeks, 6 months, and 12 months of age. End-diastolic and end-systolic measurements were made according to published standards. Mean and SEM for each of the end-diastolic and end-systolic measurements were calculated for each of 11 study periods. Data were analyzed by one-way analysis of variance, corrected for repeated measures, and in the case of right and left ventricular differences paired t tests were used for significance.
  
  
  RESULTS
  Left ventricular end-diastolic and end-systolic correlated positively with advancing age (R2 = 0.93, p < 0.0001), right ventricular end-diastolic also correlated with advancing age (R2 = = 0.361, p < 0.05), and right ventricular end-diastolic was significantly larger than left ventricular end-diastolic in utero (p < 0.01), whereas the opposite was true after birth (p < 0.0001). Heart rate significantly decreased with advancing age (p < 0.001), whereas ejection fraction for either the right or the left ventricle did not change significantly with advancing age.
  
  
  CONCLUSIONS
  This suggests that under basal conditions the ventricles can meet the increased demands in cardiac output by increasing ventricular dimensions without having to increase contractility reserve.
authors.affiliation: Department of Obstetrics and Gynecology, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, NC, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Veille
authors.forename: R
authors.initials: R
authors.lastname: Hanson
authors.forename: L
authors.initials: L
authors.lastname: Steele
authors.forename: K
authors.initials: K
authors.lastname: Tatum
mesh_terms: D002657:Child Development; D003971:Diastole; D004452:Echocardiography; D005314:Embryonic and Fetal Development; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006346:Heart Septum / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology; D006352:Heart Ventricles; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D011247:Pregnancy; D011256:Pregnancy Outcome; D013318:Stroke Volume; D013599:Systole; D016216:Ultrasonography, Prenatal