Mitral stenosis is a narrowing of the mitral valve in the heart. The mitral valve is in the left side of the heart between the upper and lower chambers of the heart. When working properly, the valve helps to keep blood flowing in the right direction from the upper to the lower chambers.

Mitral stenosis makes it difficult for blood to move from the upper and lower chambers. This means there is less blood for the lower chamber to pump out to the body. The blood can also back up in the upper chamber and push back into the lungs.

Mitral Valve Stenosis
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The most common cause of mitral stenosis is rheumatic fever. This infection that may develop after strep throat or scarlet fever and can scar the heart valves. Mitral stenosis may develop 5-10 years after this infection occurs.

Less common or very rare causes include:

  • Birth defect
  • Blood clots
  • Tumors
  • Infective endocarditis
  • Other growths that block blood flow through the mitral valve