1. “Parachute” mitral valve – a malformation of the mitral valve, the valve between the left atrium and left ventricle, in which the two valve leaflets are attached to one papillary muscle rather than two and remain close together. This results in a narrowing of the valve opening (mitral stenosis), obstructing blood flow and causing the valve to resemble a parachute in appearance.
2. Patent Ductus Arteriosus (PDA)- Blood flow is different in the fetus and most blood bypasses the lungs. An extra blood vessel (passageway) called the ductus arteriosus (DA) allows blood from the right side of the heart to flow to the aorta, one of the largest arteries, and back out into the body without going through the lungs.
After the baby is born and begins to breathe, the flow of blood changes to include the lungs. The pulmonary artery opens to carry blood from the right side of the heart to the lungs, and the DA is supposed to close.
Patent ductus arteriosus (PDA) is a condition in which the ductus arteriosus doesn't close. Patent means "open." Sometimes the open passageway is wide (a large PDA) and sometimes it is narrow (a small PDA). A large PDA is dangerous because blood flow to the lungs isn't as controlled as it should be, leading to problems with the lungs and heart.
3. Ventricular Septal Defect (VSD) – A ventricular septal defect (VSD) is an opening in the tissue (the septum) between the heart's lower chambers (the ventricles). A VSD is one of the defects that is referred to as "a hole in the heart."
When the VSD is large, the heart may have to pump harder to deliver enough oxygen to the body. Patients with a small VSD usually do not have any symptoms
4. Coarctation of the aorta – a narrowing or constriction of the aorta, the large vessel that carries blood from the heart to the body tissues
These defects all affect the left side of the heart and interfere with the flow of blood into and out of the left ventricle, which pumps oxygen-rich blood through the aorta to the body.
5. Hypoplastic Left Heart – The left ventricle is underdeveloped. It is too small. This means the heart will have to work harder and won’t last as long. Sometimes the valves entering or leaving the left ventricle are also too small.