Funding outcome

The upper chambers of the heart, the atria, receive blood from the lungs and body while the lower chambers (ventricles) are contracting. The atria then pump blood to the ventricles, to send on to the body. In the healthy heart, the ventricles are not very reliant on atrial contraction to supply blood. However, with aging and in diseases that reduce relaxation of the ventricles in adults, atrial pumping is much more important. In these conditions, subtle abnormalities of atrial function are linked to the risk of death. Little is known about how atrial function evolves in the fetus. At 6-10 weeks of pregnancy, the ventricles fill only when the atria pump, but thereafter, reliance on atrial pumping progressively decreases. This suggests important improvements in the filling function of the ventricles during pregnancy and that atrial and ventricular function evolve in tandem. We will investigate normal changes in atrial and ventricular function from 10-40 weeks of pregnancy using detailed ultrasound. We will also examine fetuses with heart diseases to see if atrial function improves to compensate in situations when ventricular function is impaired. This study will help us understand changes in heart function during normal development and how the fetal atria compensate for limitations in ventricular function. We anticipate that, in pregnancies where the atrial function does not improve to compensate for abnormal ventricular function, there is a higher risk of death. We expect to find subtle changes in atrial function detectable before abnormal ventricular function can be diagnosed, which will allow us to provide more accurate information to families about the likelihood of survival. Knowing this information will also allow us to investigate wavs to improve outcomes for these babies bv altering: our management.