Mitral Valve Stenosis – Symptoms and Causes
Overview
Mitral valve stenosis happens when the valve between the heart’s left chambers narrows. This narrowing limits blood flow into the left ventricle, which is the heart’s main pumping chamber. Many people with this condition feel tired and short of breath.
Other symptoms might include irregular heartbeats, dizziness, chest pain, or coughing up blood. Some people have no symptoms at all.
Rheumatic fever, a complication of strep throat, is a common cause of mitral valve stenosis. This condition has become rare in the United States in recent years.
Without proper treatment, mitral valve stenosis can lead to serious heart problems.
Signs and Symptoms
Mitral valve narrowing often causes few or no symptoms for many years as the condition slowly gets worse. Symptoms can start at any age, including childhood.
Common symptoms include:
- Breathing problems, especially during activity or when lying down
- Feeling tired more easily
- Swelling in feet or legs
- Irregular heartbeat sensations (pounding, skipping)
- Dizziness or fainting
- Fluid in lungs
- Chest pain or discomfort
- Coughing up blood
Symptoms often appear or worsen when your heart works harder, such as during exercise. Other stressful situations like pregnancy or infections can also trigger symptoms.
When You Should Get Medical Help
Contact your healthcare provider immediately if you experience chest pain, rapid or irregular heartbeats, or difficulty breathing during physical activity. Your provider might refer you to a cardiologist (heart specialist) for further evaluation.
If you’ve been diagnosed with mitral valve narrowing but don’t have symptoms yet, ask your healthcare team about how often you should have check-ups. Regular monitoring helps track any changes in your condition before they become serious.
Causes
Mitral valve stenosis develops when the mitral valve opening becomes narrower than normal.
This narrowing forces the heart to work harder to pump blood through the restricted opening, reducing blood flow between the upper and lower left chambers of the heart.
The most common cause of mitral valve stenosis is rheumatic fever. This inflammatory disease, which occurs as a complication of untreated strep throat, can damage the mitral valve.
People may not experience symptoms until many years or even decades after having rheumatic fever.
Calcium deposits represent another significant cause. As people age, calcium can accumulate around the mitral valve, particularly in the supporting structures. This condition, known as mitral annular calcification (MAC), can lead to stenosis symptoms when severe.
MAC often presents treatment challenges, even with surgical intervention. People who develop calcium deposits around the mitral valve frequently experience similar issues with their aortic valve as well.
Radiation therapy directed at the chest area can damage the mitral valve. The radiation can cause valve tissue to thicken and harden, typically appearing 20-30 years after treatment.
Some people are born with mitral valve stenosis as a congenital heart defect, though this occurs rarely.
Several autoimmune conditions may also lead to mitral valve stenosis:
- Lupus
- Other autoimmune disorders
The heart’s valve system is designed to maintain proper blood flow throughout the body. When the mitral valve narrows, this careful balance is disrupted, putting additional strain on the heart.
Risk Factors
Several factors can increase a person’s chance of developing mitral valve stenosis:
- Untreated Strep Throat or Rheumatic Fever: While rare in the United States, these infections remain common in developing countries and can damage heart valves when left untreated.
- Age: Older individuals face a higher risk due to calcium deposits that can build up around the mitral valve.
- Chest Radiation Therapy: People who receive radiation treatment for certain cancers may experience changes in their mitral valve structure.
- Recreational Drugs: Using MDMA (also called molly or ecstasy) increases the risk of mitral valve problems.
-
Certain Medications: Some drugs can affect heart valves:
- Migraine treatments containing ergot alkaloids (like Ergomar)
- Previously available weight-loss drugs containing fenfluramine or dexfenfluramine (such as Fen-phen, which is no longer sold in the US)
These risk factors can damage the mitral valve’s structure or function. Knowing these risks helps people understand their chances of developing this condition.
Complications
Mitral valve stenosis left untreated can lead to several serious health problems.
Irregular Heart Rhythms
People with mitral valve stenosis often develop arrhythmias, particularly atrial fibrillation (AFib). This chaotic heart rhythm becomes more common as people age and as the valve narrowing worsens.
Blood Clot Formation
The irregular heartbeats associated with mitral stenosis can cause blood to pool in the heart chambers. This pooling increases the risk of blood clots forming. If these clots break loose and travel to the brain, they can cause a stroke.
Pulmonary Hypertension
When blood flow slows or becomes blocked due to a narrowed mitral valve, pressure builds up in the lung arteries. This condition, called pulmonary hypertension, forces the heart to work harder to pump blood through the lungs.
Heart Failure on the Right Side
The changes in blood flow patterns and increased lung artery pressure strain the heart significantly. Over time, the heart muscle—especially on the right side—becomes overworked.
This extra effort eventually weakens the heart muscle, leading to right-sided heart failure as the heart can no longer pump efficiently.
Prevention
Rheumatic fever is the primary cause of mitral valve stenosis. Preventing this condition starts with avoiding rheumatic fever itself.
The most effective prevention strategy is to seek medical attention for sore throats, especially in children. When strep throat infections go untreated, they can progress to rheumatic fever.
Healthcare providers can easily treat strep throat with antibiotics when they catch it early.
