Fetal cardiology
Our Heart Center pediatric specialists treat children with a wide range of cardiovascular disorders. The types of congenital heart disease that can be diagnosed prenatally are expanding as technology constantly improves.
Evaluation of the four chambers of the heart is part of the routine ultrasound examination done by many obstetricians as part of their routine prenatal care around the 20th week of pregnancy. If an obstetrician sees an abnormality in any of the chambers, the valves, or blood vessels, he or she usually refers the patient to a pediatric cardiologist.
The Heart Center's fetal / neonatal medicine team can perform a fetal echocardiogram, which is a specialized, focused ultrasound (sonogram) study of the baby's heart while he is still inside the mother's womb. This test produces detailed pictures of the heart's structures and may include a Doppler study, which identifies and measures details of blood flow. The direction, speed, and volume of blood within the heart and blood vessels can be calculated to better identify problems in this area.
Pregnant mothers may also be referred for a fetal echocardiogram if some aspect of the pregnancy suggests an increased risk of delivering a baby with a heart problem. Among the many reasons possible for increased risk are a positive family history (a blood relative with a heart problem), an abnormal genetic screening result (abnormal nuchal translucency, serum screening, or chromosome number), a maternal health condition such as diabetes or rubella (German measles), or other known birth defect in the baby such as diaphragmatic hernia.
The function of the heart
The heart is a pump that pushes our blood in two circulation patterns. In one, the heart pushes blood to the lungs to receive oxygen (before birth the blood goes not to the lungs but to the placenta or "afterbirth"). In the other system, the heart pushes blood to all the different parts of the body to supply them with oxygen and food. Blood on the way back from the body parts carries carbon dioxide and waste products.
In the normal body, the heart has two sides, right and left, and each pumps blood into one of the circulation systems. The right side of the heart pumps blood to the lungs (or to the placenta before birth), the left side pumps to the rest of the body. In both systems, blood is pumped away from the heart in "arteries," and blood returns to the heart in "veins." In the diagram at right, blood with low oxygen content ("deoxygenated blood") is shown by blue arrows while high oxygen("oxygenated") blood is shown by red arrows.
The heart pumps in each circulation by using two chambers on each side, one in front of the other (for a total of four). The first chamber, or "atrium," collects blood as it returns back to the heart in preparation to squirting it into the powerful pumping chamber or "ventricle." The ventricle relaxes to fill with blood as the atrium squeezes. Then, when the ventricle is full, the ventricle contracts with powerful force, pushing blood out toeither the lungs or to the body. Every time the ventricles contract (a “heart beat”), a rush of blood is pushed from the heart into the two different circulation systems. This creates the flow of blood in the body and the "heartbeat" and "pulse." It also creates the "blood pressure" which is not actually one pressure but rather two – a high and a low pressure corresponding to the heart contracting and relaxing.
The chambers of the heart and the flow of blood through the heart can be seen and measured with a specialized ultrasound ("sono") study called an echocardiogram. It can even be done before birth.
The chambers of the heart are equipped with valves that only allow blood to flow in the proper direction. This prevents blood from flowing backwards when the chambers contract. The valves are activated by the flow of blood, opening in the proper direction to allow blood to go forward, closing to prevent it from flowing backwards. The location of the valves and their names are noted in the diagram.
The activity of the muscles of the heart chambers is controlled by an electrical system, much as an auto engine is controlled. The electrical system not only coordinates the contractions of the atria and ventricles so that they work together, it also sets the speed of the contractions so as to supply the correct amount of blood needed by the body for whatever it is doing. This electrical activity can be recorded and studied with an electrocardiogram or "ECG."
Birth defects and problems of the heart
Birth defects and problems of a baby's heart can occur with any of the components of the functioning heart that we have outlined:
- Position and/or anatomy of the two atria and two ventricles (wrong place, wrong connection, or absence of one or more chambers)
- Position and/or proper connections of the arteries and veins of both circulation systems (connecting wrong things together, in the wrong places, or wrong size)
- Position and/or anatomy and/or function of the valves (failure to open or close completely, too small size, in the wrong place or total absence of a valve)
- Position and/or function of the electrical system (causing improper rhythm which can be classified as irregular “ectopy”, too fast “tachycardia”, or too slow “bradycardia”)
- Holes in the walls (‘septal defects') between chambers of the heart
- Persistence of fetal blood flow pattern after birth
- Or — most frequently, a combination of two or more of the above.
Please visit Fetal heart testing to read more about fetal echocardiograms.
When a birth defect in the anatomy of the fetal heart is identified, often a recommendation is made to obtain consultation from a surgeon specializing in problems of the heart in children, a cardiothoracic surgeon.
When fetal echocardiograms are done by cardiologists from Children's Memorial Hospital, the mother receives a full discussion of what was seen and an interpretation of what problems may exist before she leaves the office. Reports are also sent to the obstetrical caregivers involved.
Please visit each of the Children's Memorial pediatric cardiologists listed here to see where they perform fetal echocardiograms:
Scheduling an echocardiogram requires a doctor's order and can be arranged through the Institute for Fetal Health. Call 773.975.8782.