Cardiac malposition, redistribution of fetal cardiac output, and left heart hypoplasia reduce survival in neonates with congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation

Objective: To evaluate cardiac position, left ventricular (LV) mass, and distribution of fetal cardiac output in infants with congenital diaphragmatic hernia (CDH) who required extracorporeal membrane oxygenation (ECMO), and in control subjects. Study design: Echocardiograms were performed on 23 neonates with CDW shortly after birth, and repeated within 5 days of repair on ECMO in 21 infants, and on 12 infants receiving ECMO for other diagnoses, ana on 10 healthy, term neonates. Cardiac angle between the midline saggital plane and the interventricular septum was measured, and deviation from normal (45 degrees) was determined. The ratio of cross-sectional areas (proportional to news) across the pulmonary (PV) and aortic (AV) valves was determined (PV2/AV(2)) in 19 infants with CDH and in the healthy control subjects. Results: Thirteen (57%) infants with CDH survived and 10 (43%) died, with no difference in cardiac deviation before surgical repair (35 +/- 13 degrees vs 39 +/- 18 degrees). Cardiac deviation persisted after repair in nonsurvivors (27 +/- 14 degrees vs 8 +/- 9 degrees, p < 0.01), and LV mass was significantly less (1.68 +/- 0.39 vs 3.05 +/- 1.20 gm/kg, p < 0.0005). Neonates requiring ECMO for other diagnoses and well term babies did not have cardiac angle deviations; both these groups had a greater LV mass than did the infants with CDH. The PV2/AV(2) flow ratios were higher in infants with CDH (median, 1.73; range, 1.25 to 16.50) compared with those of the healthy infants (0.96, 0.79 to 1.69, p < 0.0002). Conclusions: Cardiac malposition persisted despite CDH repair in nonsurvivors with low LV mass, and fetal cardiac output was redistributed away from the left ventricle. Lung hypoplasia with reduced pulmonary flow returning to the left atrium and altered left atrial hemodynamics may result in LV hypoplasia.