What Is Mitral Atresia?
Heart & Circulatory Health Data Verified

Mitral Atresia: Valvular Birth Defect of the Bicuspid

Published on Mar 13, 2023 and last reviewed on Sep 19, 2023   -  5 min read


Mitral atresia is a congenital heart problem affecting the blood flow between the heart chambers. Read this article to know more.

What Is Mitral Atresia?

Mitral atresia is a congenital defect of the mitral valve. The mitral valve, also known as the bicuspid valve, is present between the left ventricle and left atrium. In mitral atresia, the valve is either completely closed or absent altogether. The function of the mitral valve is to allow the passage of oxygenated blood from the left atrium to the left ventricle, from which it travels through the aorta and reaches all the organs of the body during the heart relaxation phase.

The valve also prevents backflow of blood from the ventricle to the atrium in the contraction phase. This is primarily associated with mal-aligned ventricular septum with or without mal-aligned atrial septum, atrioventricular canal defect, and excessive growth of the endocardial cushion. The condition is often associated with other congenital heart defects like:

What Causes Mitral Atresia?

Mitral atresia is a rare occurrence and is found in approximately one in 10,000 live births. Although the exact cause of the developmental anomaly is yet to be determined, it is hypothesized to result from a combination of various genetic and environmental factors. Some researchers also hypothesize that the anomaly develops as a result of maternal infections or teratogenic medications. These factors also act as events that increase the risk of developing mitral atresia. Eighty percent of cases are seen in association with larger ventricular anomalies, including hypoplastic left heart syndrome, left ventricular outflow tract obstruction, and double-outlet right ventricle.

What Are the Clinical Features of Mitral Atresia?

The clinical entities of mitral atresia vary according to the severity of the condition, along with other factors (both genetic and environmental), like the presence of other cardiac defects. Some of the common symptoms include:

  • Cyanosis (bluish skin due to poor oxygen saturation).

  • Shortness of breath.

  • Fatigue.

  • Lethargy.

  • Rapid breathing (tachypnea).

  • Poor nutrition.

  • Slow weight gain.

  • Clubbing to fingers and toes.

  • Chest pain.

  • Chest discomfort.

  • Arrhythmias (irregular cardiac rhythm).

  • Abnormal heart sounds.

How to Diagnose Mitral Atresia?

If the doctor suspects any heart defect, not just mitral atresia, a team of experts perform necessary examinations, both physical and cardiac-specific tests. Primarily, breath sounds and heartbeats are analyzed, along with evaluating signs of oxygen deprivation, in the form of cyanosis. Some of the possible findings of a physical examination include:

  • Tachycardia (above 150 bpm).

  • Displacement of the apex.

  • Grade three systolic murmur in first, second, and third heart sounds.

  • Tachypnoeic (respiratory cycles above 50 per minute).

  • Low oxygen saturation (below 85 percent and may improve on intubation).

Following this, additional tests may be ordered to confirm a diagnosis. These tests include:

  • Chest Radiograph: Chest X-rays may show a variable degree of cardiomegaly (enlargement of the heart).

  • Echocardiogram: This uses sound waves to paint a picture of the heart and its valves while it is functioning. This is used to clearly visualize mitral defects. The great vessels may be normally positioned. A hypoplastic left ventricle, right ventricular hypertrophy, and the aortic arch on the left side may be some of the echo findings.

  • Electrocardiogram (ECG): ECG shows any anomaly in the electrical activity of the heart. The track may show sinus tachycardia.

  • Cardiac Catheterization: This is an invasive test involving the introduction of a flexible tube into an artery and guided to the heart. This can help evaluate the blood flow and pressure within the heart and also detect and confirm the presence of any structural anomaly like mitral atresia or any additional defect accompanying mitral atresia.

  • Cardiac MRI: Another test that may be performed is a cardiac MRI (magnetic resonance imaging). However, cardiac MRI and catheterization may not be necessary as echo studies can provide sufficient evidence for the diagnosis and pathophysiological analysis.

How to Treat Mitral Atresia?

The treatment is tailored to meet the patient’s condition, and it depends largely on the severity and overall health of the baby. Sometimes conservative therapies may be sufficient to manage the abnormality, while in some cases, surgical interventions may be required. Pharmacotherapeutics involves prescriptions of diuretics, vasopressors, and antibiotics. Supportive therapies may include oxygen and mechanical ventilation.

Surgical interventions may be required in deteriorating cases or in patients with high severity of anomaly. Shunts and staged corrective surgeries are planned and performed, but sometimes they may require further, more complex surgeries. In most rare cases, a complete heart transplant may just be the only way to save the patient. However, that road is long and requires specific criteria to be fulfilled to even get listed in the UNOS (United Network for Organ Sharing) list. The list is dynamic, and finding a match is like searching for a needle in a haystack. Multiple parameters like blood typing, tissue typing, and cross-matching have to be satisfied in both donor and recipient to be able to schedule a transplant.

What Are the Complications of Mitral Atresia?

  • Heart failure (inability of the heart to pump blood efficiently).

  • Arrhythmias (irregular heartbeat).

  • Cyanosis.

  • Thrombosis (clotting within the vessels).

  • Stroke (damage to the brain due to insufficient blood supply).

  • Pulmonary embolism (pulmonary arteries get blocked by a clot).


Mitral atresia is a congenital heart anomaly that affects the structure and function of the bicuspid valve, the one that guards the passage of the left chambers. The condition, untreated or undiagnosed, can precipitate a range of complications or may even cause death in infants with severe anomalies. Almost four-fifths of the reported cases are accompanied by several other cardiac anomalies; hence the patients may require a much higher degree of care and a great many hours in the operation theater. Regular checkups with concerned specialists and medical teams, stringent compliance with medication, and a medically chartered lifestyle can help improve the quality of life. It is of utmost importance to seek medical help immediately if one notices any symptoms or worsening of general health.

Article Resources

Last reviewed at:
19 Sep 2023  -  5 min read




Comprehensive Medical Second Opinion.Submit your Case

Related Questions & Answers

I have a small womb, one of my tubes did not function properly, and I lost my first pregnancy. Can I get pregnant again?

Query: Hello doctor, My boyfriend and I have been trying to have a baby for four years. We visited a physician who started blood investigations, such as the HSG test for me and a sperm test for my boyfriend. I found out I was pregnant three days after inserting the dye in my tubes for the HSG. I carried my...  Read Full »

Fetal ultrasound failed to detect heartbeat. Has the child been aborted?

Query: Hello doctor, My wife's last period date was two months ago. After one month, we came to know that she is pregnant. She had her first ultrasound 10 days ago and the baby is fine at five weeks and five days with a heartbeat of 114. But for the last three to four days, she saw some blood in her urine....  Read Full »

Absence of Pericardium - Types, Symptoms, Diagnosis, and Management

Article Overview: The absence of pericardium is a rare condition of unknown etiology. Such conditions are often silent and show no symptoms needing surgical intervention. Read Article

Isaac Gana
Isaac Gana

Introduction The absence of pericardium is also called pericardial agenesis. It is the non-occurrence of the outer covering of the heart. It is a congenital disorder. This has a prevalence of 0.0002 % and has been found more in males as compared to females. The defect can be a complete, incomplete, ...  Read Article

Popular Articles Most Popular Articles

Do you have a question on Congenital Abnormalities or Mitral Atresia?

Ask a Doctor Online

* guaranteed answer within 4 hours.

Disclaimer: No content published on this website is intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek advice from your physician or other qualified healthcare providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website. Read our Editorial Process to know how we create content for health articles and queries.