Mitral Regurgitation

Mitral regurgitation, also known as mitral insufficiency, is a defect in which the mitral valve does not close properly. As a result, blood leaks (regurgitates) from the left ventricle into the left atrium, reducing the amount of blood circulating throughout the body. In addition, over time, the atrium may dilate due to volume overload.

According to its severity, mitral regurgitation is classified into three grades:

• Mild mitral regurgitation: the regurgitant flow is minimal and scarcely interferes with normal cardiac function. It usually does not cause symptoms or complications.
• Moderate mitral regurgitation: a significant amount of blood regurgitates, leading to enlargement of the left atrium and reduced pumping capacity of the ventricle.
• Severe mitral regurgitation: the regurgitant volume is high, and the increased pressure in the atrium and ventricle results in congestive heart failure and pulmonary involvement.

Mitral regurgitation causes difficulty for blood to flow into the ventricle, prompting atrial enlargement to accommodate the excess volume. If this condition persists over time, the lungs may become affected.

The prognosis of mitral regurgitation varies depending on the degree of valvular involvement. When diagnosed early and treated appropriately, full restoration of valve function may be achieved. However, heart failure can develop if the cardiac chambers sustain permanent damage due to valvular dysfunction. Life expectancy in patients who are not candidates for surgical treatment is significantly reduced, with mortality rates of approximately 50% within two years.

Symptoms

Chronic mitral regurgitation may remain asymptomatic for a prolonged period. When symptoms do appear, they may develop gradually or occur suddenly. The most common symptoms include:

• Chest pain, often worsened by physical exertion.
• Fatigue and a persistent feeling of exhaustion.
• Fluid accumulation in the ankles (edema).
• Arrhythmias: irregular heartbeats and palpitations.
• When pulmonary involvement occurs:
  • Dyspnea: shortness of breath.
  • Dry cough.

Causes

The causes of mitral regurgitation can be divided into two main groups:

• Primary mitral regurgitation: caused by an anatomical defect of the valve.
  • Mitral valve prolapse: valvular components rupture or elongate, protruding into the left atrium and preventing proper closure.
  • Enlargement of the annulus forming the valve, resulting in inadequate closure.
  • Congenital valve abnormalities.
• Secondary mitral regurgitation: the valve anatomy is normal, but another cardiac condition prevents proper closure.
  • Coronary artery disease: hardening of the coronary arteries alters the anatomy of the left ventricle and the papillary muscles connecting the ventricular interior to the valve, resulting in ischemic mitral regurgitation.
  • Rheumatic fever: inflammation of cardiac tissues following streptococcal infection may cause fibrosis and stiffening of the mitral valve, impairing closure.
  • Myocardial infarction: damage to the muscle supporting the mitral valve prevents normal function.
  • Cardiomyopathy: thickening of the myocardium reduces pumping capacity, affecting valve function.
  • Infective endocarditis: infection-induced inflammation of the endocardium and valves prevents complete valve closure.
  • Systemic lupus erythematosus: autoimmune-related tissue overgrowth may produce vegetations that interfere with mitral valve function.
  • Marfan syndrome: connective tissue disorder that may cause thickening of the mitral valve, impairing proper closure.

Risk Factors

Factors that increase the risk of developing mitral regurgitation include:

• Advanced age: more common after 75 years.
• Personal history of other valvular heart diseases.
• Previous chest radiation therapy.
• Congenital heart defects.
• Conditions related to the causes of the disease:
  • Coronary artery disease.
  • Rheumatic fever.
  • Myocardial infarction.
  • Cardiomyopathy.
  • Infective endocarditis.
  • Systemic lupus erythematosus.
  • Marfan syndrome.

Complications

In most cases, mitral regurgitation does not cause complications. However, if it progresses undetected, it may worsen, weaken the heart muscle, and lead to:

• Cardiac enlargement: specifically dilation of the left atrium and left ventricle.
• Atrial fibrillation: a cardiac rhythm disorder characterized by irregular and excessively rapid heartbeats.
• Pulmonary hypertension: increased pressure in the pulmonary arteries.
• Congestive heart failure: inability of the heart to pump blood effectively, resulting in blood accumulation in cardiac chambers and fluid overload in the lungs and other organs.

Prevention

Mitral regurgitation cannot be prevented; however, complications may be reduced by maintaining a healthy lifestyle and controlling cardiovascular risk factors. General recommendations include:

• Following a balanced diet rich in fruits and vegetables and low in fat.
• Engaging in regular physical activity.
• Avoiding tobacco use and limiting alcohol consumption.
• Maintaining a healthy body weight.
• Getting adequate sleep.
• Controlling hypertension.
• Preventing infections whenever possible:
  • Maintaining good oral hygiene.
  • Frequent handwashing.
  • Receiving recommended vaccinations.
  • Following medical advice.

Which doctor treats mitral regurgitation?

Mitral regurgitation is managed by specialists in cardiology and cardiovascular surgery.