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The Amazing Heart and How it Works

When a child is diagnosed with CHD, their Sibley pediatric cardiologist is often called on to explain how the heart works so parents can better understand their child’s condition. Most of us never think twice about the function of this important organ, taking for granted how it works – day in and day out – to keep us alive and healthy. But when something goes wrong, it becomes essential information, and Sibley doctors are excellent teachers.

The single purpose of this fist-sized muscle is to pump oxygen and nutrient-rich blood throughout our bodies, beating 100,000 times per day and pumping about 2,000 gallons per day. It is a vital part of a person’s cardiovascular system, which includes all the blood vessels that carry blood from the heart to the body’s tissues and back again.

The heart has four chambers separated by a wall of tissue called the septum and aided by four heart valves (tricuspid, pulmonic, mitral and aortic) that open and close with flaps, allowing blood to flow in only one direction.

The two upper chambers of the heart are the atria, which receive incoming blood from the body. The right atrium receives deoxygenated blue blood from the body, while the left atrium receives oxygenated red blood from the lungs. For fetal circulation, there is a special hole shunt between the left and right atria called the foramen ovale that diverts blood away from the lungs and goes directly to the rest of the fetus’s body. This hole typically closes after birth.

The lower two chambers of the heart are the ventricles. The right ventricle receives deoxygenated blue blood from the right atrium and pumps it into the lungs to be filled with oxygen, while the left ventricle receives red oxygen-rich blood from the left atrium and pumps it out to the body.

Congenital heart defects may involve a valve, a chamber, the septum, an artery or a blood flow issue. Some CHDs, such as atrial septal defect (ASD) and ventricular septal defect (VSD), can be detected when a doctor listens to the heart with a stethoscope and hears a “murmur.”

The heart is designed in such as a way that it handles a very specific volume of blood,” said Andrew Dodgen, M.D., Sibley pediatric cardiologist. “In the case of ASD or VSD, extra blood is leaking into the pathways, and as it passes through the heart, it causes turbulence that can be heard.”

More severe forms of CHD may manifest in decreased oxygen levels (turning blue), swelling of the hands, feet and face or enlargement of the liver.

Check out this video of Dr. Dodgen teaching kids how to draw a heart.

Resources: The free Heartpedia app from Cincinnati Children’s Hospital provides 3-D models of the heart, allowing a view from both outside and inside the organ.

For more information about Sibley Heart Center Cardiology and our pediatric cardiology specialists, click here.

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