The ductus arteriosus is a blood vessel that connects the pulmonary artery (main vessel supplying the blood to the lungs) to the aorta (main vessel supplying the blood to the body). This connection is present in all babies in the womb, but should close shortly after birth. In some babies, especially in those born prematurely, this vessel may remain open. This is called a patent or persistent ductus arteriosus.
Hypoplastic left heart syndrome is a condition where the left lower pumping chamber (left ventricle) of the heart does not develop properly so is much smaller than usual. The mitral valve between the left ventricle and the upper left filling chamber (left atrium) is often closed or very small.
An atrioventricular septal defect results in a is a large hole between the upper filling chambers (atria) and the lower pumping chambers (ventricles) of the heart. There is also only one valve between the atria and ventricles instead of two.
Aortic regurgitation occurs when the aortic valve (linking the left ventricle to the aorta) does not close properly when the heart contracts. This means blood leaks back into the left ventricle, which then has to work harder to pump the extra blood away from the heart to the rest of the body. This can lead to the enlargement and thickening of the ventricle wall.
Langerhans' cell histiocytosis (LCH) is a very rare condition with a high survival rate. Histiocyte cells normally help protect the skin, but sometimes the body has too many of them and they move around the body, causing damage.