The heart has four chambers that work together to make sure that blood and oxygen is distributed throughout the body. The right side of the heart, which holds the blood that needs oxygen, is separated from the left side with its oxygenated blood. In many congenital heart problems, that separation does not exist. This leads to problems for the infant.
Basic Anatomy
The two upper chambers are called atria, while the two lower chambers are called ventricles. A wall named the interatrial septum separates the two atria from each other, while an interventricular septum separates the two ventricles.
Normal Flow of Blood
Blood comes into the right atrium and then goes to the right ventricle. It leaves the ventricle through the pulmonary artery to go to the lungs. The oxygenated blood then goes to the left atrium, passes to the left ventricle, and leaves the heart through the aorta. The blood circulates throughout the body, distributing its oxygen, and returns to the right side of the heart, to begin the cycle again.
Ventricular Septal Defect
Dr. Miyamoto, of the Department of Pediatrics at the University of Colorado School of Medicine, writes that this is the most common congenital heart problem. An opening in the interventricular septum allows blood to abnormally flow from the left ventricle to the right ventricle. If the defect is small, the baby will not have any symptoms at birth. However, if the defect is large, there will be so much blood passing to the right ventricle, that the pressure will increase and cause that ventricle to become dilated. This can lead to right heart failure. In addition, because less oxygenated blood is circulating throughout the body, the infant will not be able to grow properly. This is termed "failure to thrive."
Atrial Septal Defect
In this congenital heart problem, there is an opening in the interatrial septum. This allows blood to abnormally flow from the left atrium to the right atrium. As in the ventricular septal defect, if the defect is small, the infant will not have any symptoms at birth. And if the defect is large, there will be too much blood for the right ventricle, which increases the pressure in that ventricle and dilates it, resulting in right heart failure. Again the infant will suffer from "failure to thrive.
Patent Ductus Arteriosus
The fetus does not need its blood to go to the lungs, because it gets oxygenated blood from the mother. Thus, there is a duct, called the ductus arteriosus, which diverts blood from the pulmonary artery to the aorta. If this duct does not close within a few days after the baby is born, it is referred to as the patent (open) ductus arteriosus. Since the pressure in the aorta is higher than the pressure in the pulmonary artery, instead of blood going from the aorta to deliver oxygen throughout the body, some of it is diverted to the pulmonary artery and back to the lungs. If the patent ductus arteriosus is small, the infant will not have any symptoms. But if the opening is large, the infant will have "failure to thrive," have many pneumonias and possible heart failure.
References
- "Current Diagnosis & Treatment: Pediatrics"; William Hay, Jr., M.D., Myron Levin, M.D., Judith Sondheimer, M.D., Robin Deterding, M.D.; 2009
- "Handbook of Pathophysiology"; Elizabeth Corwin, MSN, PhD, FNP; 2000
