Mitral atresia is a rare congenital heart defect where the mitral valve, which normally allows blood to flow from the left atrium to the left ventricle, is either completely closed (imperforate) or absent. This blockage prevents blood from flowing properly through the heart.
Here's a more detailed breakdown:
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Definition: Mitral atresia is a congenital non-syndromic heart malformation characterized by an imperforate or absent mitral valve.
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Key Characteristics:
- Absent or Imperforate Mitral Valve: The primary characteristic is the missing or completely closed mitral valve.
- Univentricular Heart: In many cases, blood flows from both atria into a single ventricle, usually the right ventricle. This is described as a univentricular atrioventricular connection to a dominant right ventricle via a tricuspid valve.
- Hypoplastic Left Ventricle: The left ventricle is often underdeveloped (hypoplastic) due to the lack of blood flow through it during development.
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How it Affects Blood Flow: Because the mitral valve is blocked, blood cannot flow directly from the left atrium to the left ventricle. This disrupts the normal circulatory pathway. To survive, infants with mitral atresia require other heart defects, such as an atrial septal defect (ASD) or patent ductus arteriosus (PDA), to allow blood to reach the systemic circulation. These defects allow blood to bypass the blocked mitral valve.
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Treatment: Treatment typically involves multiple surgeries to redirect blood flow or, in some cases, a heart transplant. The specific surgical approach depends on the other associated heart defects.
In summary, mitral atresia is a serious and complex congenital heart defect requiring specialized medical care.
