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. Rheumatic fever can damage the heart valves leading to rheumatic heart disease. Mitral stenosis resulting from RHD is called rheumatic mitral stenosis.  Although most mitral stenosis is caused by RHD, it can also result from a calcium build up on the heart valves. This is more common in older patients and is called calcific mitral stenosis. 

Is mitral valve stenosis treatable?

Although medications can’t fix a valve defect, they can help with symptoms. Your health care team 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. The choice of procedure is based on many factors including the cause of the mitral stenosis (rheumatic or calcific), condition of the valve, risk of surgery, severity of symptoms, heart function, and availability of procedures.

Mitral Valve Commissurotomy
For rheumatic mitral stenosis, a commissurotomy may be performed. During this procedure the valve leaflets that have become fused together are separated. This can be done using a balloon (percutaneous mitral balloon commissurotomy or PMBC) or surgery. In both cases, once the leaflets have been separated, the valve opening is increased and blood flow through the valve is improved. In more advanced rheumatic mitral valve stenosis, surgical repair or replacement of the mitral valve may be required. 


(* 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