Left atrium: one of the four chambers of the heart. The left atrium receives blood full of oxygen from the lungs and then empties the blood into the left ventricle. Back to Articles Related Articles Hypoplastic Left Heart Syndrome (HLHS) Hypoplastic left heart syndrome (HLHS) is a birth defect of a baby’s heart. The left side of the heart doesn’t grow as it should, making it smaller and weaker than normal. Read More Dictionary: Aorta The aorta is the major blood vessel that carries blood away from the heart to the rest of the body. Read More Dictionary: Blalock-Taussig (BT) shunt A Blalock-Taussig (BT) shunt is a small, soft tube that lets blood in the body be redirected. Read More Dictionary: Blood Pressure Blood pressure is a measurement that tells how hard the heart is pumping to move blood through the blood vessels. Read More Dictionary: Heart Transplant A heart transplant is a surgery where doctors remove a person's sick heart and replace it with a healthy donor heart. Read More Dictionary: Inferior Vena Cava The inferior vena cava is the large vein that returns blood from the legs and abdomen to the heart. Read More Dictionary: Interstage Period Babies with hypoplastic left heart syndrome (HLHS) need three surgeries. The time between the first and second surgeries is called the interstage period. Read More Dictionary: Left Ventricle The left ventricle pumps blood full of oxygen out to the body. Read More Dictionary: Open-Heart Surgery Open-heart surgery is surgery that involves opening the chest and heart. A heart-lung machine does the work for the heart and lungs during the procedure. Read More Dictionary: Sano shunt A Sano shunt is a small, soft tube that lets blood in the body be redirected. Read More Dictionary: Single Ventricle Defect Having a single ventricle means that only one of the heart's two ventricles (pumping chambers) works well enough to pump blood. Read More Dictionary: Superior Vena Cava The superior vena cava is the large vein that returns blood from the head and arms to the heart. Read More Heart and Circulatory System The heart and circulatory system are our body's lifeline, delivering blood to the body's tissues. Brush up on your ticker with this body basics article. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.