Aortic Stenosis主动脉狭窄.doc
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Aortic Stenosis主动脉狭窄
What is aortic stenosis?什么是主动脉狭窄？
Aortic stenosis is a heart defect that may be congenital (present at birth) or acquired (develop later in life). If the problem is congenital, then something occurred during the first 8 weeks of pregnancy to affect the development of the aortic valve. 主动脉狭窄是一种心脏病，可能是先天性的(出生时就有的)或者获得性的(在以后的生活中产生的)。如果是先天性的，那么在妊娠最初的8周里发生了什么事影响到主动脉瓣的发育。
The aortic valve is found between the left ventricle and the aorta. It has three leaflets that function like a one-way door, allowing blood to flow forward into the aorta, but not backward into the left ventricle. Aortic stenosis is the inability of the aortic valve to open completely.主动脉瓣位于左心室和主动脉之间。它有三个瓣叶，功能象一个单向们，允许前向血流进入主动脉，但不能返流回左心室。主动脉狭窄使得主动脉瓣不能够完全的开放。
With aortic stenosis, problems with the aortic valve make it harder for the leaflets to open and permit blood to flow forward from the left ventricle to the aorta. In children, these problems can include a valve that:主动脉狭窄的问题在于主动脉瓣狭窄使得瓣膜开放和血流从左心室到主动脉遇到困难。在儿童，可能有以下的情况：
* only has one or two leaflets instead of three.一瓣或两瓣化代替三个瓣叶。
* has leaflets that are partially fused together.瓣叶部分的融合在一起。
* has thick leaflets that do not open all the way.瓣叶增厚不能充分开放。
* becomes damaged by rheumatic fever or bacterial endocarditis.由于风湿热或细菌性心内膜炎造成损害。
Aortic stenosis may be present in varying degrees, classified according to how much obstruction to blood flow is present. A child with severe aortic stenosis will be quite ill, with major symptoms noted early in life. A child with mild aortic stenosis may have few symptoms, or perhaps none until later in adulthood. The degree of obstruction can become worse with time.主动脉狭窄可以有不同的严重程度，分级依据血流受到阻碍的严重程度。一位严重的主动脉狭窄的患儿在生命的早期严重的症状就已经显著，将会是严重的病态，一位较轻的主动脉狭窄的患儿可能有很少的症状或者可能没有症状，直到后来到了成年期才有症状。阻碍的程度随着时间的推移可能变得更严重。
Congenital aortic stenosis occurs in 3 to 6 percent of all children with congenital heart disease. Relatively few children are symptomatic in infancy, but the incidence of problems increases sharply in adulthood.先天性主动脉狭窄的发病率占所有先天性心脏病患儿的3-6%。相当少数的患儿在婴儿期出现症状，但是在成年期问题的发生氯急剧增加。
Congenital aortic stenosis occurs four times more often in boys than in girls.主动脉狭窄发生在男性较女性多4倍。
What causes aortic stenosis?什么原因引起主动脉狭窄？
Congenital aortic stenosis occurs due to improper development of the aortic valve in the first 8 weeks of fetal growth. It can be caused by a number of factors, though, most of the time, this heart defect occurs sporadically (by chance), with no apparent reason for its development.主动脉狭窄的发生是由于在胎儿生长发育的前8周里主动脉瓣的不正常的发育。虽说多个因素可以引起，但多数还是偶发的(偶然的)，没有明显的原因导致它。
Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families.有些先天性的心脏缺陷可能有遗传链，由于基因缺陷，抑或染色体异常，或环境暴露，引起心脏问题在某些家庭多发。
Acquired aortic stenosis may occur after a strep infection that progresses to rheumatic fever.发展成风湿热的链球菌感染之后获得性主动脉狭窄可能发生 ......
Aortic Stenosis主动脉狭窄
What is aortic stenosis?什么是主动脉狭窄？
Aortic stenosis is a heart defect that may be congenital (present at birth) or acquired (develop later in life). If the problem is congenital, then something occurred during the first 8 weeks of pregnancy to affect the development of the aortic valve. 主动脉狭窄是一种心脏病，可能是先天性的(出生时就有的)或者获得性的(在以后的生活中产生的)。如果是先天性的，那么在妊娠最初的8周里发生了什么事影响到主动脉瓣的发育。
The aortic valve is found between the left ventricle and the aorta. It has three leaflets that function like a one-way door, allowing blood to flow forward into the aorta, but not backward into the left ventricle. Aortic stenosis is the inability of the aortic valve to open completely.主动脉瓣位于左心室和主动脉之间。它有三个瓣叶，功能象一个单向们，允许前向血流进入主动脉，但不能返流回左心室。主动脉狭窄使得主动脉瓣不能够完全的开放。
With aortic stenosis, problems with the aortic valve make it harder for the leaflets to open and permit blood to flow forward from the left ventricle to the aorta. In children, these problems can include a valve that:主动脉狭窄的问题在于主动脉瓣狭窄使得瓣膜开放和血流从左心室到主动脉遇到困难。在儿童，可能有以下的情况：
* only has one or two leaflets instead of three.一瓣或两瓣化代替三个瓣叶。
* has leaflets that are partially fused together.瓣叶部分的融合在一起。
* has thick leaflets that do not open all the way.瓣叶增厚不能充分开放。
* becomes damaged by rheumatic fever or bacterial endocarditis.由于风湿热或细菌性心内膜炎造成损害。
Aortic stenosis may be present in varying degrees, classified according to how much obstruction to blood flow is present. A child with severe aortic stenosis will be quite ill, with major symptoms noted early in life. A child with mild aortic stenosis may have few symptoms, or perhaps none until later in adulthood. The degree of obstruction can become worse with time.主动脉狭窄可以有不同的严重程度，分级依据血流受到阻碍的严重程度。一位严重的主动脉狭窄的患儿在生命的早期严重的症状就已经显著，将会是严重的病态，一位较轻的主动脉狭窄的患儿可能有很少的症状或者可能没有症状，直到后来到了成年期才有症状。阻碍的程度随着时间的推移可能变得更严重。
Congenital aortic stenosis occurs in 3 to 6 percent of all children with congenital heart disease. Relatively few children are symptomatic in infancy, but the incidence of problems increases sharply in adulthood.先天性主动脉狭窄的发病率占所有先天性心脏病患儿的3-6%。相当少数的患儿在婴儿期出现症状，但是在成年期问题的发生氯急剧增加。
Congenital aortic stenosis occurs four times more often in boys than in girls.主动脉狭窄发生在男性较女性多4倍。
What causes aortic stenosis?什么原因引起主动脉狭窄？
Congenital aortic stenosis occurs due to improper development of the aortic valve in the first 8 weeks of fetal growth. It can be caused by a number of factors, though, most of the time, this heart defect occurs sporadically (by chance), with no apparent reason for its development.主动脉狭窄的发生是由于在胎儿生长发育的前8周里主动脉瓣的不正常的发育。虽说多个因素可以引起，但多数还是偶发的(偶然的)，没有明显的原因导致它。
Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families.有些先天性的心脏缺陷可能有遗传链，由于基因缺陷，抑或染色体异常，或环境暴露，引起心脏问题在某些家庭多发。
Acquired aortic stenosis may occur after a strep infection that progresses to rheumatic fever.发展成风湿热的链球菌感染之后获得性主动脉狭窄可能发生 ......
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