Problem: Mitral Valve Stenosis

Stenosis animation

What is mitral valve stenosis?

Mitral stenosis is a narrowing of the mitral valve opening. Mitral stenosis restricts blood flow from the left atrium to the left ventricle.

Watch a mitral valve stenosis animation.

What problems can result from untreated or advanced mitral valve stenosis?

Mitral stenosis causes reduced blood flow through the narrowed valve opening from the left atrium to the left ventricle. As a result, the volume of blood bringing oxygen from the lungs is reduced. This can make you feel tired and short of breath. The volume and pressure from blood remaining in the left atrium increases which causes the left atrium to enlarge and fluid to build up in the lungs.

What causes mitral valve stenosis?

Mitral stenosis can be caused by congenital heart defects, mitral valve prolapse, rheumatic fever, lupus and other conditions. Rheumatic fever (PDF) is a childhood illness that sometimes occurs after untreated strep throat or scarlet fever.

Rheumatic fever is rare in high-income countries such as the United States but remains a concern in some low- and middle-income nations.

Two conditions not related to valve stenosis that can mimic it by producing the same symptoms are:

  • Myxoma (a benign tumor in the left atrium)
  • Nearby blood clot that reduces blood flow through the mitral valve

Is mitral valve stenosis treatable?

Although medications can’t fix a valve defect, they can help with symptoms. Your health care provider may prescribe diuretics to reduce fluid accumulation in the lungs, blood thinners* to prevent clots from forming, or drugs to control the heart rhythm if those are indicated. The mitral valve can usually be repaired or replaced with surgery, or a minimally invasive procedure.


(* Some medications are commonly called blood thinners because they can help reduce a blood clot from forming. There are three main types of blood thinners that patients commonly take: anticoagulants like warfarin or heparin, antiplatelet drugs like aspirin, and fibrinolytics like tPA (tissue plasminogen activator). Each type of medication has a specific function to prevent a blood clot from forming or causing a blocked blood vessel, heart attack, or stroke.)

Heart Valve Disease Resources

Find out more about your heart valves and how to manage heart valve disease.

Valve Stenosis: When a Heart Valve is Too Narrow
Understanding Heart Murmurs, Aortic and Mitral Valve Problems