How does the normal heart work?
There are 4 chambers in the heart, 2 upper chambers called the right atria and left atria and 2 lower chambers called the right ventricle and left ventricle. Blood comes from the body and goes into the right atria. It then flows through the tricuspid valve into the right ventricle where it is pumped into the lungs to get oxygenated through the pulmonary artery. After traveling through the blood vessels in the lungs, the blood returns to the heart through 4 pulmonary veins in to the left atria. From the left atria, the blood goes into the left ventricle through the mitral valve and then gets pumped out to the body through the aorta. This cycle repeats itself with every heartbeat. (see diagram below). www.cdc.gov/ncbddd/heartdefects/facts.html
Below you will find some examples of different types of congenital heart disease. Congenital means that this problem occurred during the development of your baby early on in pregnancy.
At the end you can find links to different sites that have additional information.
Hypoplastic Left Heart Syndrome (HLHS)
What is it?
This is a congenital heart defect where the left side of the heart didn't develop normally. Remember, as described in the section on how the normal heart works, the left side of the heart pumps oxygenated blood through the aorta to the body. There are 3 main defects, or problems, in babies with HLHS: The first is that the mitral valve that separates the left atria and the left ventricle is too small or closed; the second is that the left ventricle is underdeveloped and very small, and the third is that the aortic valve is very small or not present (like the mitral valve) which leads to underdevelopment of the aorta. These defects lead to decreased blood to the body and if not corrected will lead to death.
(Diagram of HLHS)
How is it treated?
The good news is that in the 1980's a surgery was developed to help fix the problems seen in this congenital heart defect; the surgery is done in 3 stages. The pediatric cardiologist and the pediatric cardiothoracic surgeon will go over in detail how the surgery will be performed; and remember there may be small differences in how the surgeon will do the surgery if your baby's HLHS has slight differences or variations in the defect compared to the typical baby with HLHS. So briefly, there are 3 stages to fixing HLHS which will create normal blood flow into and out of the heart to the body can get the oxygenated blood that it needs to survive.
1. The first stage is called the Norwood procedure (named after the surgeon who developed it). This surgery will usually be done within the first week of life. In this initial surgery, the right ventricle is converted into the main ventricle that will pump blood to the body (essentially doing what the left ventricle would normally do). This is done by using the pulmonary artery (the vessel that connects the right ventricle to the lungs) and attaching it to the aorta that is underdeveloped so it essentially creates a new aorta. So now the blood from the right ventricle can go out into the body. But how does the blood get into the lungs to be oxygenated now? This is done by using a special tube, called a BT shunt, that connects the right pulmonary artery to one of the vessels that connects to the aorta. So what this does now is when the blood goes out from the right ventricle through the new aorta some of the blood will go to the body and some of the blood will go through the BT shunt to the lungs to be oxygenated.
(Diagram of Norwood procedure for HLHS)
2. The second stage, or second surgery for HLHS, is called either the hemi-Fontan or bidirectional Glenn procedure.
(Diagram of hemi-fontan procedure)
3. The third stage is called the Fontan procedure.
(Diagram of the Fontan procedure)
Tetralogy of Fallot (TOF)
Transposition of the Great Arteries (TGA)
Ventricular Septal Defect (VSD)
This is the most common type of congenital heart defect. A VSD is a hole in the wall, or septum, of the lower 2 chambers of the heart (the right and left ventricle). They can range in size from very small to large. When a VSD is present, it allows blood from the left side of heart to flow into the right side of the heart which increases the amount of blood that goes into the lungs. The extra blood that is going into the lungs causes the heart and lungs to work harder and can cause problems over time like increased blood pressure in the lungs, heart failure, or irregular heart rhythms. Closing a VSD will prevent these complications from happening.
Most of the time a VSD doesn't need to be repaired immediately after birth. Depending on the size and location, it may even close on its own. Your baby will be monitored by a pediatric cardiologist after discharge from the hospital to determine if your baby will require surgery. Some of the common symptoms that you will be watching for is increased work of breathing, decreased energy, especially for feeding (becoming too tired to finish the usual amount of food he/she takes) which can lead to poor weight gain, and/or sweating with mild exertion.
(Diagram of VSD)
Atrial Septal Defect (ASD)
An atrial septal defect (ASD) is a hole between the upper 2 chambers of the heart (the right and left atria). Some ASDs will close on their own, usually by the time the child is 2 years old. If they do not close, or they are causing problems, then they will need to be closed either by surgery or cardiac catheterization. An ASD allows blood to flow from the left atria to the right atria which increases the amount of the blood in the right side of the heart and subsequently an increased amount of blood going into the lungs. Overtime this can cause right heart failure because of the increased stress on the right side of the heart from having to pump extra blood and can cause damage to the blood vessels in the lungs called pulmonary hypertension.
(diagram of ASD)
Coarctation of the Aorta
Total Anomalous Pulmonary Venous Return (TAPVR) or Partial Pulmonary Venous Return (PAPVR)
Atrioventricular Septal Defect