What is cor triatriatum?

Cor triatriatum is a rare congenital heart condition where a fibrous, muscular membrane separates the left upper chamber of the heart (left atrium) into two sections. In a healthy heart, the left atrium is a single chamber that receives oxygen-rich blood from the lungs and sends it to the left lower chamber (left ventricle), which then pumps blood to the rest of the body.

In a heart with cor triatriatum, the left atrium has two sections. One section receives oxygen-rich blood from the pulmonary veins, while the other section sends blood to the left ventricle. There is usually a hole in the membrane, which allows blood to pass between these two sections. The size of the hole can be different for every child.

If the hole in the membrane is small, it can make it harder for blood to flow from the lungs and into the lower part of the heart. This can cause blood to back up in the lungs and reduce the amount of blood being pumped to the rest of the body.

Cor triatriatum is often found along with another condition called an atrial septal defect, which is a hole in the septum between the atria. 

Signs and symptoms of cor triatriatum

Your child’s symptoms are based on the size of the hole in the membrane and whether your child also has an atrial septal defect. 

Symptoms of cor triatriatum may include: 

• Heart murmur, or abnormal heart sound when a doctor listens with a stethoscope
• Fatigue or shortness of breath, especially while eating or exercising
• Blue or purple tint to lips, skin and nails (cyanosis)

Testing and diagnosis for cor triatriatum

Several different tests may be used to diagnosis cor triatriatum. 

• Electrocardiogram (EKG or ECG), which is a record of the electrical activity of the heart
• Echocardiogram (also called echo or ultrasound), which is when sound waves create an image of the heart
• Chest X-ray
• Pulse oximetry, which is a noninvasive way to monitor the amount of oxygen in the blood

Treatment for cor triatriatum

At the Cardiac Center at Children’s Hospital of Philadelphia (CHOP), our doctors are among the most experienced in the nation in cor triatriatum repair. To repair cor triatriatum, a surgeon will remove the muscular membrane in the left atria. If there is also an atrial septal defect, the surgeon will close it using either a patch or sutures.

After surgery, your child will initially recover in the Evelyn and Daniel M. Tabas Cardiac Intensive Care Unit (CICU), where they will receive round-the-clock attention from a team of dedicated cardiac critical care medicine specialists. As their condition improves, they will be cared for in the Cardiac Care Unit until they are well enough for discharge.

Follow-up care 

Through age 18 

After repair, most children recover quickly and don't have additional heart problems. Additional surgery is rarely required. However, children with cor triatriatum must see a pediatric cardiologist for regular checkups. 

Into adulthood

Our pediatric cardiologists follow patients until they are young adults. The Philadelphia Adult Congenital Heart Center, a joint program of CHOP and Penn Medicine, meets the unique needs of adults who were born with heart defects.  

At CHOP’s Cardiac Center, we support our adolescent and young adult patients through a smooth and seamless transition to adult cardiology care at the Philadelphia Adult Congenital Heart Center or, if desired, to a cardiologist with congenital heart disease expertise in another location. 

Long-term outlook for children with cor triatriatum

Because of enormous strides in medicine and technology, today nearly all children with cor triatriatum go on to lead healthy, productive lives as adults.