M-MODE ECHOCARDIOGRAPHIC EVALUATION OF FETAL AND INFANT HEARTS - LONGITUDINAL FOLLOW-UP-STUDY FROM INTRAUTERINE LIFE TO YEAR ONE

OBJECTIVE: Our purpose was to evaluate cardiac variables, including ri ght and left end-diastolic and end-systolic dimensions by use of M-mod e echocardiography during fetal, neonatal (transitional),and infancy p eriods to understand hemodynamic adaptation during these periods. STUD Y DESIGN: Fifty-three fetuses were enrolled in this study. Echocardiog raphy evaluations were started as early as the sixteenth week of gesta tion and were repeated every 4 to 6 weeks until term, on postnatal day s 1 and 2, and at 6 weeks, 6 months, and 12 months of age. End-diastol ic and end-systolic measurements were made according to published stan dards. Mean and SEM for each of the end-diastolic and end-systolic mea surements were calculated for each of 11 study periods. Data were anal yzed by one-way analysis of variance, corrected for repeated measures, and in the case of right and left ventricular differences paired t te sts were used for significance. RESULTS: Left ventricular end-diastoli c and end-systolic correlated positively with advancing age (R(2) = 0. 93, p < 0.0001), right ventricular end-diastolic also correlated with advancing age (R(2) = 0.361, p < 0.05), and right ventricular end-dias tolic was significantly larger than left ventricular end-diastolic in utero (p < 0.01), whereas the opposite was true after birth (p < 0.000 1). 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. CONCLUSION: This sugg ests that under basal conditions the ventricles can meet the increased demands in cardiac output by increasing ventricular dimensions withou t having to increase contractility reserve.