article_snippet: The mitral valve between the left ventricle and the upper left filling chamber is often closed or very small.
article_snippet: In addition, the main blood vessel that carries blood from the heart to the rest of the body is also smaller than usual.
article_snippet: This means that the heart is unable to pump blood around the body effectively.
article_snippet: In children with a condition in which the left lower pumping chamber of the heart (left ventricle) does not develop properly, the valve between the left ventricle and the upper left filling chamber (left atrium) if often closed or small.
article_snippet: The main blood vessel that carried blood from the heart to the rest of the body the body is also smaller than usual.
article_snippet: This means the heart is unable to pump blood effectively around the body.