The heart is divided into four major chambers, the left atrium, left ventricle, right atrium and the right ventricle. The valve present between the left atrium and the left ventricle is called the mitral valve. The valve present between the right atrium and the right ventricle is called the tricuspid valve. Narrowing of the mitral valve, in medical terms is called Mitral stenosis (MS). This narrowing leads to an increase in resistance to the flow of the blood from the atrium to the ventricle which leads to the manifestation of most of the symptoms.
Causes of Mitral Stenosis
MS can be caused due to a variety of diseases. One of the most common causes is Rheumatic Heart Disease, but with the advent of antibiotics, the incidence of rheumatic heart disease has been on aa steady decline. Other causes are:
- Rheumatic heart disease
- Systemic lupus erythematosus (SLE)
- Congenital: defect in the heart at birth
Some conditions may cause symptoms like MS without an actual narrowing of the valves:
- Cardiac myxoma
- Clot in the left atrium
- In some cases of endocarditis
Symptoms of Mitral Stenosis
Many individuals with mitral stenosis are asymptomatic. If you have mitral stenosis you might experience:
- Difficulty in breathing
- Shortness of breath on lying down
- Chest pain
- Blood in cough
- Acute awareness of your heartbeat
- Swelling in both feet
The symptoms of MS worsen with increased blood flow to the heart like during exercise and pregnancy.
Diagnosis of Mitral Stenosis
To reach to the diagnosis of MS your doctor will like to do a thorough physical examination after talking to you. Your doctor will hear your heart with a stethoscope to look for signs of a ‘murmur’. Murmurs are sounds produced by the heart which may be the sign of a particular disease; sometimes healthy people may also have a murmur. To confirm the findings of the physical examination your doctor might order some tests like:
- Electro Cardiogram (ECG) : in this test a few metal leads will be kept over your chest to record the electrical activity of your heart.
- Chest X-ray: the narrowing of the valve leads to an enlargement of the left atrium; this can be seen on a chest X ray.
- Trans Thoracic Echocardiography (TTE): a probe which emits sound waves will be kept over your heart by the echocardiographer to look at your heart and its valves in action, this will help your doctor assess the severity of the narrowing and hence help in planning further treatment.
- Trans-esophageal Echocardiography (TEE): in this procedure a sonography probe will be inserted via your mouth into your food pipe to better visualise the left atrium, and look for clots in the left atrium. This procedure will also help in deciding the future course of action.
- Cardiac Catheterization: a small tube (catheter) is inserted into an artery in your groin and taken till the heart to assess the severity of the stenosis. This procedure can be used for treatment and diagnosis simultaneously.
Complications of Mitral Stenosis
- Mitral stenosis causes an increase in the workload of the heart, and untreated can lead to numerous complications like:
- Atrial fibrillation: the narrowing of the mitral valve causes the left atrium to increase in size; this predisposes you to rapid irregular contractions of the atrium which can sometimes be felt by the person.
- Pulmonary Hypertension: Increased pressure is generated in the left atrium to ensure the passage of blood through the narrowed heart valve; this increase in pressure in the left atrium is reflected in the blood pressure of the vessels in the lungs, a condition called pulmonary hypertension. Increased blood pressure in the lung blood vessels may overwork the right side of the heart eventually leading to Right heart failure.
- Blood clots: Atrial fibrillation predisposes your heart to formation of blood clots in your atrium. These blood clots may get dislodged and go into the circulation in your body leading to stroke or a heart attack.
Treatment of Mitral Stenosis
The treatment for MS aims to prevent further complications and alleviate symptoms. They include
- Medical treatment:
- Anticoagulants to prevent formation of clot inside the heart chamber.
- Anti-arrhythmic drugs to prevent the episodes of rapid and erratically changing heart rate
- Diuretics: to prevent fluid build up in your lungs because of pulmonary hypertension
- Antibiotics: prevent rheumatic fever
- Beta blockers or calcium channel blockers: to reduce your heart rate hence making sure that it is able to function adequately
- Percutaneous Balloon Mitral Valvuloplasty: a small tube is inserted into the artery in your groin of arm and guided to the heart. When it reaches the valve a balloon is inflated to breakdown the commissure between the valves which were causing the narrowing. This procedure being less invasive is preferred, but cannot to help all the individuals. You may talk to your doctor to decide if PBMV can be considered for you
- Surgical management: A cardiac surgeon will perform an open heart surgery to either repair or replace the valve in your heart. You will be put on a heart-lung bypass machine during the surgery. Individuals with a replaced heart valve will have to be on blood thinners through out their life.