Mitral Stenosis - Causes, Symptoms, Diagnosis, and Treatment

Introduction

Mitral stenosis, also known as mitral valve stenosis, is a heart valve disease involving the narrowing of the mitral valve. The mitral valve is the valve connecting the chambers of the left side of the heart. It allows blood to flow between the left atrium and left ventricle. When the mitral valve gets narrowed or blocked, the blood flow between the chambers is reduced. The oxygen supply to the heart is compromised, causing breathing difficulty. The most common cause of mitral stenosis is rheumatic fever. Mitral stenosis is more likely to occur in women than in men. In developed countries like the United States, the prevalence of mitral stenosis is 1 in 100000. But in developing countries like Africa, the prevalence is 35 in 100000.

What Are the Causes of Mitral Valve Stenosis?

• Rheumatic Fever - It is the most common cause of mitral stenosis. Rheumatic fever is an overreaction of an untreated bacterial infection. Mitral stenosis caused by rheumatic fever is called rheumatic mitral stenosis. Mitral stenosis usually occurs 20 to 40 years after an episode of rheumatic fever. A streptococcus infection is the most common cause of rheumatic fever.

• Congenital Heart Defect - Some children are born with mitral stenosis. Usually, it is detected before the age of two years. If it goes undetected, the children may not live more than five years.

• Calcification of the Mitral Valve - As people age, calcium deposits inside the valves. It will narrow the valve and cause mitral stenosis.

• Radiation Therapy - It is a method of treating cancer. When radiation is done in the chest area, the mitral valve tends to shrink, and it causes mitral valve stenosis.

Other medical conditions like systemic lupus erythematosus, rheumatoid arthritis, malignant carcinoid syndrome, and other autoimmune diseases can cause mitral stenosis.

What Are the Symptoms of Mitral Valve Stenosis?

There are no symptoms of mild mitral stenosis. The symptoms are as follows;

• Breathing difficulty is the most common symptom. It is more prominent while doing physical activity or lying down.

• Heart palpitations (being aware of one's own heartbeat).

• Fatigue during increased physical activity.

• Swelling of the feet.

• Blood on the cough.

• Chest pain or discomfort.

• Bronchitis (inflammation of the tubes that carry air to and from the lungs).

• Stroke.

• Hoarseness of the voice.

What Are the Risk Factors for Mitral Valve Stenosis?

• Old Age - Aging increases calcium deposits in the valve. So old age increases the risk of mitral stenosis.

• Untreated Bacterial Infections - Untreated bacterial infections like streptococcus infections can increase the risk of mitral stenosis.

• Illegal Drug Abuse - Use of 3, 4-methylenedioxymethamphetamine, also known as MDMA, can increase the risk of mitral stenosis.

• Radiation Therapy - In the chest area can cause the mitral valve to narrow in some cases leading to mitral stenosis.

• Other Medications - Ergotamine is a kind of medicine given for migraine. It rarely causes mitral stenosis.

How Is Mitral Stenosis Diagnosed?

• Clinical Examination - To detect a heart murmur (abnormal heart sounds).

• Echocardiogram - Using ultrasound waves, a picture of the inside of the heart is created. This is the most common test for the diagnosis of mitral stenosis.

• Chest X-ray - Using x-rays, changes in the structure and shape of the heart caused by mitral stenosis are detected.

• Electrocardiogram - Measures the electrical activity of the heart using sensors mounted on the chest. Although an electrocardiogram can detect heart rhythm problems related to mitral stenosis, it is generally insufficient for a complete diagnosis.

• Cardiac CT and MRI - CT (computerized tomography) and MRI (magnetic resonance imaging) are done to get detailed images of the heart to detect the severity of mitral stenosis.

• Cardiac Catheterization - By means of a device inserted into a blood vessel and connected to the heart, the pressure in the heart is measured to determine mitral stenosis.

• Exercise Echocardiogram - Heart functioning is recorded while walking on a treadmill to get the status of the heart while doing physical activity.

What Is the Treatment of Mitral Valve Stenosis?

Medical Therapy

Although medical therapy cannot relieve the obstructions in the mitral valve, it is used to treat the symptoms of mitral stenosis. The different types of medications given are:

• Diuretics to prevent fluid accumulation in the body.

• Beta-blockers or calcium channel blockers to decrease heart rate.

• Anticoagulants for thinning the blood to prevent the clotting of blood.

• Antibiotics are given to high-risk patients before dental procedures.

• Antiarrhythmics to treat atrial fibrillation (irregular heart rhythm).

Surgical Therapy

• Percutaneous Mitral Balloon Valvuloplasty (PMBV) - Involves widening of the narrowed valve by inserting a catheterized balloon. It is done only in symptomatic patients or in asymptomatic patients with hypertension.

• Mitral Valve Replacement Surgery - It is done in patients where balloon valvuloplasty is not possible. Indicated for patients with severe mitral stenosis. For patients with artificial heart valves, lifelong anticoagulants are recommended.

• Open Surgery for Valve Repair - It is done in patients where a catheter procedure is impossible. Through an open surgery, calcium deposits and scar tissue are removed that are blocking the mitral valve.

What Are the Complications of Mitral Valve Stenosis?

• Heart failure.

• Pulmonary hypertension (increased pressure inside the blood vessels going from the heart to the lungs).

• Endocarditis (inflammation of the inner lining of the heart).

• Stroke (when the blood supply to the brain is blocked, it leads to brain damage).

• Failure to thrive.

Conclusion

Mitral stenosis is a heart valve disease in which the mitral valve gets blocked due to different kinds of reasons. The primary cause that can lead to mitral stenosis is a history of rheumatic fever. It does not show any symptoms until it gets severe. Bacterial infections like streptococcus should be treated timely to prevent mitral stenosis. Early diagnosis and timely treatment give the best outcome for mitral valve stenosis. Age-related mitral stenosis is generally unavoidable. However, it may be delayed by regular exercise, maintenance of a healthy weight, a healthy diet, and getting a yearly health check. A low-salt diet is recommended in patients with mitral stenosis. Also, restraining physical activities is needed because the heart cannot bear that much strain. Regular follow-up is required after the treatment for mitral stenosis.