二尖瓣狭窄是二尖瓣阻塞，the cardiac valve separating the left atrium from the left ventricle.When the mitral valve is narrowed,the flow of blood from the left atrium to the left ventricle becomes reduced.二尖瓣狭窄在发达国家相对少见，但当它发生时，会引起严重的心脏问题。
The mitral valve controls the opening between the left atrium and the left ventricle.When the left atrium contracts,the mitral valve opens to allow blood to flow into the left ventricle.一旦左心室充满，它就会收缩，把血液泵到体外，二尖瓣关闭，防止血液倒流到左心房。
二尖瓣狭窄，二尖瓣变厚，不能移动（也就是说，狭窄的）无法完全打开。When this occurs,左心房不能完全排空进入左心室。不完全排空导致左心房压力升高。经过很长一段时间，会导致严重的心脏问题。
Several conditions can produce mitral stenosis:
- 风湿性心脏病是最常见betway手机平台的病因of mitral stenosis.Because rheumatic betway手机平台heart disease has become rare in developed countries,mitral stenosis is now seen much less frequently than it was in past decades.
- 某些形式的先天性心脏病可导致二尖瓣狭窄。betway手机平台In these cases,二尖瓣发育不正常。
- 二尖瓣环钙化（二尖瓣上形成钙沉积的情况，usually in association with with aging or kidney disease) can cause mitral stenosis.二尖瓣环钙化是一种很常见的情况，更常见的原因是二尖瓣反流and only rarely produces mitral stenosis.
- 感染性心内膜炎(infection of the heart valves) can very rarely result in mitral stenosis.
What Problems Does Mitral Stenosis Cause?
风湿性心脏病引起的二尖瓣狭窄（最常见的原因）betway手机平台the valve problem develops slowly,over a period of years,and symptoms appear gradually.在大多数情况下，the mitral stenosis is first diagnosed 15 to 20 years afterrheumatic fever已经发生了。
在此期间，左心房内的压力逐渐升高，最后，这个腔体变大了。The increased pressure is also transmitted backwards,肺中的血管，and eventually to the pulmonary artery.肺动脉高压，肺动脉高压，通常是结果。
心房颤动在二尖瓣狭窄患者中很常见。Up to 70% of people with mitral stenosis will eventually develop this arrhythmia.
血栓栓塞症二尖瓣狭窄也是一个问题。在异常的左心房内形成的血凝块脱落并造成组织损伤，尤其地stroke.This problem is a risk in anybody with atrial fibrillation,but that risk is especially high when the atrial fibrillation is associated with mitral stenosis.事实上，即使不存在房颤，二尖瓣狭窄也可能发生血栓栓塞。
二尖瓣狭窄最常见的症状是呼吸困难（呼吸急促）cough,and fatigue.二尖瓣狭窄的人最有可能在心脏需要做更多的工作时经历这些症状。比如在任何类型的运动中，emotional stress,发烧或其他疾病,or pregnancy.
正如二尖瓣狭窄本身逐渐发展，so do the symptoms it causes.In many cases,people with mitral stenosis avoid symptoms by subconsciously reducing their activity level over a period of years,eventually becoming quite sedentary.Because they are so inactive,他们通常不会注意到呼吸问题，可能不会向医生报告这种症状。
当二尖瓣狭窄变得严重时，patients may develop persistent symptoms even at rest,也可能出现严重的水肿，and begin to cough up blood.
Arial fibrillation can produce palpitations and lightheadedness,and can make all the symptoms associated with mitral stenosis much worse.
The diagnosis is often first suspected after the doctor performs a physical examination and notices the soft,rumbling heart murmur that is characteristic of mitral stenosis.Once the diagnosis is suspected,it can be easily confirmed or ruled out with anechocardiogram.
Treating Mitral Stenosis
如果你被诊断出二尖瓣狭窄，the most important things you and your doctor will have to consider are whether/when to perform a surgical procedure to relieve the stenosis,and what steps need to be taken to prevent血栓形成.
二尖瓣狭窄是一种严重的心脏病，通常需要多年的时间来发展。在这段时间内，这往往会逐渐产生症状。Often,当一个二尖瓣狭窄的人向他们的医生抱怨症状时，the condition is quite advanced.The earlier this condition is diagnosed,however,手术治疗越成功。