What is Mitral Stenosis?
Mitral stenosis (MS), a type of heart valve disease, happens when the mitral valve in your heart becomes too narrow. The most common reason for this condition today is a disease called rheumatic fever. However, the narrowing from this condition usually takes many years before it starts to cause noticeable health issues.
What Causes Mitral Stenosis?
The most frequent reason for mitral stenosis, a condition where the heart’s mitral valve narrows, is a disease called rheumatic fever. There are also less common reasons such as the hardening of the mitral valve leaflets, which are the thin layers of tissue that open and close to let blood flow through, and congenital heart diseases, which are conditions present at birth.
Other causes of mitral stenosis can include infective endocarditis, an infection of the inner lining of your heart; mitral annular calcification, a condition where calcium deposits build up in the ring-like part of the mitral valve; endomyocardial fibroelastosis, a rare heart disorder affecting children and young adults; malignant carcinoid syndrome, a group of symptoms that occur in people with carcinoid tumors; systemic lupus erythematosus, an immune system disease; Whipple’s disease, a rare bacterial infection; Fabry disease, a disorder that affects many parts of the body; and rheumatoid arthritis, a long-term autoimmune disorder that primarily affects joints.
Risk Factors and Frequency for Mitral Stenosis
Rheumatic disease is becoming less common in developed countries, with about 1 in 100,000 people being diagnosed. However, in developing countries it’s more common than in the United States. For example, in Africa, there are 35 cases per 100,000 people.
- Rheumatic mitral stenosis, a type of rheumatic disease, is more often found in females.
- It typically starts to show up between the ages of 30 and 40.
Signs and Symptoms of Mitral Stenosis
Mitral stenosis, which typically appears 20 to 40 years after a person has rheumatic fever, can cause a variety of symptoms such as shortness of breath when lying down, sudden respiration troubles at night, palpitations, chest pain, spitting blood, blood clots when the left heart chamber is enlarged, fluid buildup in the belly, swelling, and an enlarged liver if right heart failure happens. People might also feel more tired and weaker than usual with physical activities or during pregnancy.
During a physical examination, a healthcare provider would use a stethoscope to listen to the patient’s heartbeat. They may hear specific sounds that suggest mitral stenosis. One of them is a loud first heart sound, which might even be felt, because of the increased force needed to close the mitral valve. If the pulmonary pressure is very high due to mitral stenosis, the pulmonic component of the second heart sound will also sound loud.
Another sign is the so-called opening snap, an additional sound that occurs when the pressure in the left atrium is greater than the pressure in the left ventricle. This results in the forceful opening of the mitral valve after the first component of the second heart sound.
The healthcare provider might also hear a rumbling murmur during the middle resting phase of the heartbeat after the opening snap. This sound is most clear when the patient is lying down on their left side or doing isometric exercises. It indicates the advanced stage of mitral stenosis, which could be coupled with signs of right-sided heart failure such as an enlarged jugular vein, increase in the ribs’ movement, an enlarged liver, and the buildup of fluids, and/or high pulmonary pressure.
Other signs of mitral stenosis could include a fast and irregular heartbeat (atrial fibrillation), an increase in left-side rib movements due to high pulmonary pressure, and a pulsation of the apex of the heart.
Testing for Mitral Stenosis
Mitral stenosis, or narrowing of the heart’s mitral valve, is evaluated through a variety of tests. The noninvasive ones include electrocardiograms (ECGs), chest X-rays, and echocardiograms which are different types of heart tests that do not require surgery or any medical procedure. Exercise echocardiograms are also used and is a test that assesses the heart’s response to physical exertion. An invasive procedure used for this purpose is called cardiac catheterization, which involves threading a thin tube into a blood vessel and up to your heart.
An ECG can show signs of left atrial enlargement which means that the left upper part of your heart has become larger than normal. It can also detect abnormal heart rhythms, such as atrial fibrillation.
A chest X-ray, in the early stages, typically shows a normal heart size but may show some changes like enlarged main pulmonary arteries and displacement of the esophagus by an enlarged left atrium. In severe cases, the chest X-ray will show enlargement of all the heart chambers along with the pulmonary arteries and veins.
An echocardiogram, which uses sound waves to create images of the heart, helps in assessing the shape, size, and movement of heart parts. In the case of mitral stenosis, it helps understand the condition of the mitral valve leaflets (the flaps that control blood flow) and whether there’s any thickening or calcification (hardening because of calcium deposits).
An exercise echocardiogram helps in measuring blood flow across the mitral valve and the pressure in the pulmonary artery, both at rest and during exercise.
Cardiac catheterization is typically used when noninvasive tests do not provide conclusive results or when there’s a discrepancy between the test results and the patient’s symptoms.
The severity of mitral stenosis is categorized into four stages, varying from ‘At risk of MS’ where there are no symptoms, to ‘Symptomatic Severe MS’ where the person experiences decreased exercise tolerance or shortness of breath during exertion.
The Wilkins Score is used to assess the condition of the mitral valve and can range from Grade 1 (minor changes) to Grade 4 (significant changes).
Treatment Options for Mitral Stenosis
For the treatment of mitral stenosis, which is a narrowing of the heart valve that controls blood flow from the lungs into the heart’s chamber, there are a few options. These include medication, a specific non-surgical procedure called percutaneous mitral valvuloplasty, and surgery. With this said, it’s important to know that no medication can remove an existing blockage in the mitral valve. The intention with medication here is to prevent certain heart diseases, improve symptoms, and lower the risk of blood clots.
One possible heart disease that can arise due to mitral stenosis is endocarditis. To prevent its occurence, at-risk patients are given certain medications before they undergo any dental procedures that involve manipulating gum tissue or courtesy wound in mouth’s lining tissue. Usually, high-risk patients are those who’ve either had heart valve replacement or repair, or have previously suffered infected endocarditis, or have had a cardiac valvuloplasty.
Preventive treatment against rheumatic fever, which’s a complication of throat infection that can damage the mitral valve, may be administered with Benzathine Penicillin in patients who have strep throat.
Patients suffering from mitral stenosis often have a normal rhythm of heart beat, this phenomenon is called sinus rhythm. In this case, the role of medication is to alleviate symptoms. For instance, water pills or diuretics are used to relieve congestion, while beta-blockers and calcium channel blockers can help with symptoms that arise during physical exertion due to an increase in heart rate.
In some cases, a patient may have a fast and irregular heart rate known as atrial fibrillation due to mitral stenosis. Here, the first course of action is to control this through medication that blocks signals that increase heart rate. However, if a patient is unwell, they may need a procedure called direct current cardioversion to stabilize the heart’s rhythm. If atrial fibrillation can’t be controlled this way, then the primary goal turns to controlling the rate of heartbeat. Preferably, for a stable patient, reverting back to a normal heart beat is chosen over rate control to enhance their fitness level and quality of life.
Finally, anticoagulation medication to prevent blood clots is recommended in those with mitral stenosis and atrial fibrillation, a history of blood clots, or a confirmed left atrial clot. Right now, Warfarin is the go-to anticoagulant for clot prevention. Nonetheless, it needs to be monitored using a blood test called INR to ensure that the right levels are being maintained. Notably, aspirin or other anti-clotting drugs are not approved for reducing blood clot risks exclusively due to mitral stenosis.
Percutaneous mitral balloon valvuloplasty is an invasive procedure to treat mitral stenosis. It works by increasing the mitral valve area and decreasing the pressure across the valve. This procedure is only recommended for symptomatic patients with a functional score higher than II by the New York Heart Association, or asymptomatic patients with pulmonary hypertension having moderate or severe stenosis and a favorable valve structure, but no left atrial blood clot or moderate to severe mitral leakage.
Lastly, in cases where the balloon procedure is not possible or not successful and the patient still has bothersome moderate or severe mitral stenosis symptoms, then surgery to replace the mitral valve could be a potential treatment option.
What else can Mitral Stenosis be?
Medical conditions like:
- Left atrial myxoma (a rare, noncancerous tumor in the heart)
- Endocarditis (an inflammation of the inner layer of the heart)
What to expect with Mitral Stenosis
Mitral valve stenosis is a heart condition that can often go unnoticed for many years, especially if it’s caused by a disease like rheumatic fever. It can even take decades to notice any signs of Mitral valve stenosis after an episode of rheumatic fever.
However, once symptoms start showing, the disease tends to get more serious very quickly, especially when it’s related to rheumatic fever. It’s important to note that around 80% of patients with this condition might not live more than ten years from when the symptoms first started showing. For those with high blood pressure in the lungs (pulmonary hypertension) due to mitral valve stenosis, the average survival span is about three years. Also, heart failure often hits when the condition gets more severe.
For children born with this heart condition, their future depends a lot on how severe their condition is. These kids often need to be regularly checked for heart-related issues throughout their lives.
Possible Complications When Diagnosed with Mitral Stenosis
Heart disease can result in various complications like:
- Heart failure
- Stroke
- Failure to thrive
- Pulmonary hypertension
- Endocarditis
Preventing Mitral Stenosis
For people living with severe mitral valve stenosis, which is a narrowing of one of the heart’s valves, it may be necessary to limit physical activity to avoid putting too much stress on their heart. There might also be a need for dietary changes, such as eating a low-sodium diet.
All individuals with mitral valve stenosis may need to take certain medications. These can help prevent potential complications like strokes, high blood pressure (hypertension), and heart failure. As the requirement for these medications can span a lifetime, it’s crucial for the person to understand the importance of taking them consistently and as prescribed. The commitment to taking medicine as directed is critical in managing this condition effectively.
