Abnormalities in ventricular function in human fetuses with congenital heart disease

Congenital heart disease (CHD) has been associated with increased risk of fetal growth retardation, hydrops, and demise. Purpose: Our aim was to determine if human fetuses with CHD have decreased left ventricular systolic function compared to fetuses with normal hearts (NML). Methods; 37 consecutive CHD and 37 NML fetal echos from 55 pregnancies matched for maternal age and race and fetal gestational age and sex were analyzed retrospectively. CHD fetuses had a variety of anatomic cardac lesions, including six patients with neural crest-related heart defects. Hemodynamic variables in NML and CHD fetuses were compared using paired t-tests and two-way ANOV. Results: Interobserver variability of left ventricular dimensions, cardiac output, stroke volume, and heart rate was low, averaging 12%. Heart rate was equal in NML and CHD fetuses. Left ventricular (LV) diastolic area (2.15 ± 1.02 cm², NML; 2.28 ± 1.21, CHD) and volume were slightly higher in NML fetuses, compared to CHD (r≤0.08). LV systolic area (0.99 ± 0.60 cm², NML; 30% ± 0.80, CHD) and length (1.50 ± 0.47 cm, NML; 1.67 ± 0.51, CHD) were significantly higher in CHD fetuses (p≤.05). LV volume ejection fraction (72.9 ± 8.8%, NML; 65.3 ± 7.7, CHD) was significantly lower in CHD fetuses (p≤002). Stroke volume and cardiac output (0.27 ±0.13 1/min, NML; 0.27 ± 0.17 CHD, p≤ 0.92) were not different between NML and CHD fetuses. Conclusion: Human fetuses with CHD have decreased LV systolic function compared to healthy fetuses. Despite mildly decreased LV function, stroke volume and cardiac output are maintained at normal levels. In conditions requiring elevation of cardiac output (e.g., birth), myocardial reserve may be reduced.