Mitral Valve Disease

The Mitral Valve, located between the left heart chambers, left atrium and left ventricle, doesn’t work properly. It may not be closing properly, which causes blood to leak backward to the left atrium (regurgitation), or the valve may be narrowed (stenosis). As a result, the heart does not pump enough blood out of the left ventricular chamber to supply the body with oxygen-filled blood.

The heart has four valves that keep blood flowing in the correct direction. These valves include the mitral valve, tricuspid valve, pulmonary valve and aortic valve. Each valve has flaps (leaflets or cusps) that open and close once during each heartbeat. Sometimes, the valves don't open or close properly, disrupting the blood flow through the heart to the body.

Types

• Mitral valve regurgitation:
  • The flaps (leaflets) of the mitral valve don’t close tightly, causing blood to leak backward into the left atrium.
  • If untreated, it can result in heart muscle damage.
  • It is commonly caused by mitral valve prolapse, in which the leaflets bulge back into the left atrium as the heart contracts.
• Mitral valve stenosis:
  • The flaps of mitral valve become thick or stiff, and they may fuse together. This results in a narrowed valve opening and reduced blood flow from the left atrium to the left ventricle.
  • Stenosis is the least common, accounting for less than 1% of cardiac diagnoses in the United States
  • Treatment depends on the severity and whether it worsens. Surgery may be recommended to repair or replace the mitral valve.
• Mitral valve prolapse:
  • Prolapse occurs when the flaps on the valve bulge instead of closing tightly. This might prevent the valve from closing completely, and regurgitation — the backward flow of blood — may occur.
  • Prolapse is the most common, occurring in up to 5% of the population

Symptoms

• Symptoms of any type of mitral valve disease usually develop gradually.
• They might appear or get worse when the body is dealing with extra stress, such as infection or pregnancy.
• There might be no symptoms or no symptoms for many years
• Abnormal heart sound (Heart murmur) heard through a stethoscope
• Fatigue
• Shortness of breath, particularly with exercise or when lying on back
• Irregular heartbeat or fast heartbeat
• Cough
• Pain or tightness in the chest
• Lightheadedness

Causes

Mitral valve disease has many causes. Some forms of mitral valve disease can be present at birth (congenital heart defect). Each form of mitral valve disease has its own set of causes.

• Mitral valve stenosis occurs when the flaps or leaflets of the valve thicken, stiffen or fuse together. This results in a narrowing of the valve and prevents the valve from fully opening, restricting the blood flow through the valve.
  • is typically caused by scarring from rheumatic fever. Usually a childhood disease, rheumatic fever results from the body’s immune response to a streptococcal bacterial infection. Rheumatic fever is a serious complication of strep throat or scarlet fever.
  • Various parts of the heart can become inflamed and lead to these potentially serious heart conditions, including:
    • endocarditis: inflammation of the lining of the heart
    • myocarditis: inflammation of the heart muscle
    • pericarditis: inflammation of the membrane surrounding the heart
  • Mitral stenosis is uncommon in the United States and other developed countries where rheumatic fever is rare because of they generally have access to antibiotics to treat bacterial infections.
  • Most cases of mitral stenosis in the United States are in older adults who had rheumatic fever before the widespread use of antibiotics or in people who have moved from countries where rheumatic fever is common.
  • Other causes include: blood clots, calcium buildup, congenital heart defects, radiation treatments & tumors.
• Mitral valve prolapse often has no specific or known cause.
  • It tends to run in families or occur in those who have other conditions, such as scoliosis and connective tissue problems.
  • According to the American Heart Association, about 2 percent of the U.S. population has a mitral valve prolapse. Even fewer people experience serious problems associated with the condition.
• Mitral valve regurgitation occurs when the leaflets of the mitral valve don’t close tightly, allowing a portion of the blood to leak back into the heart’s left atrium (upper left heart chamber) rather than flowing forward.
  • can be caused by problems with the mitral valve, also called primary mitral valve regurgitation.
  • Often caused by mitral valve prolapse, in which the mitral valve flaps (leaflets) bulge back into the left atrium.
  • Diseases such as endocarditis, heart attack and rheumatic fever
  • Damage to the heart’s tissue cords or wear and tear to the mitral valve can also lead to regurgitation.
  • Mitral valve prolapse can sometimes cause regurgitation.

Risk factors

Several factors can increase your risk of mitral valve disease, including:

• Older age
• History of certain infections that can affect the heart
• History of certain forms of heart disease or heart attack
• History of use of certain drugs
• Heart conditions present at birth (congenital heart disease)
• Radiation to the chest

Complications

• Irregular heart rhythms in the upper heart chambers (atrial fibrillation)
• High blood pressure that affects the blood vessels in the lungs (pulmonary hypertension)
• Blood clots
• Heart failure
• Stroke
• Enlarged heart
• Death

Diagnosis

• Imaging tests: Echocardiogram, x-ray, transesophageal echocardiogram, cardiac catheterization, electrocardiogram (ECG or EKG), holter monitoring
• Stress tests

Treatment

Treatment for mitral valve disease may not be necessary, depending on the severity of your condition and symptoms. If severe enough, there are three possible treatments or combination of treatments.

• Drugs & medication - there are no medications that can actually fix the structural issues with your mitral valve. Some medications can ease your symptoms or prevent them from getting worse.
• Valvuloplasty - in cases of mitral valve stenosis, the doctor may be able to use a balloon to open up the valve
• Open-heart surgery – in severe cases, surgical repair or mitral valve replacement may be necessary.

Resources & additional reading

• [https://www.mayoclinic.org/diseases-conditions/mitral-valve-disease... Mayo Clinic – Mitral valve disease
• Healthline – Mitral Valve Disease
• Frankel Cardiovascular Center, Michigan Medicine – Mitral Valve Disease
• AHA Journals – Mitral Valve Disease by Zoltan G Turi. Originally published 17 Feb 2004
• The Patient Guide to Heart, Lung, and Esophageal Surgery – Mitral Valve Disease
• Mitral valve disease – YouTube video