The mitral valve allows blood to flow from the left atrium down into the left ventricle, and it is a part of the high pressure environment of the left side of the heart. Mitral valve regurgitation (also called mitral insufficiency or mitral incompetence) is an abnormality that occurs when the valve does not close properly, allowing blood to leak backward into the left atrium. Mitral valve regurgitation is graded from mild to severe based on the amount of backflow. In time, it causes a pressure buildup in the lungs. Untreated valve disease can lead to congestive heart failure, cardiomyopathy, stroke, arrhythmia, or blood clots.
What Causes Mitral Valve Regurgitation?
Historically, the most common cause of mitral valve regurgitation was rheumatic fever during childhood. Although the incidence of rheumatic fever has decreased significantly due to the use of antibiotics for strep throat infections, it still exists today. Another infection that damages the heart valves is called bacterial endocarditis or infective endocarditis. Severe high blood pressure and heart attack can also damage the mitral valve and lead to mitral regurgitation.
Symptoms depend on the patient and the severity of the mitral regurgitation. Some patients experience no symptoms. In other cases, mitral valve disease takes its toll over many years. Symptoms may develop slowly, and include:
• Shortness of breath or fast breathing
• Abnormal arrhythmias or palpitations (e.g., a fast or fluttering pulse)
• Chest pain
Importantly, these symptoms are likely to occur or worsen during exercise or physical exertion.
Heart valve disease is diagnosed by listening to the heart with a stethoscope; diseased heart valves make distinct clicking sounds or murmurs. Other diagnostic tests that are used to determine the underlying cause, complexity, and severity of heart valve disease include a chest x-ray, blood tests, an echocardiogram (transthoracic or transesophageal), electrocardiography (ECG) or Holter monitoring, exercise stress testing, electrophysiology (EP) studies, cardiac catheterization, and diagnostic imaging scans, such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET). A careful and complete diagnostic workup will help determine the timing and composition of the treatment plan.
Treatment for mitral valve regurgitation depends on its type and severity. Asymptomatic patients may not need treatment. In some cases, careful monitoring is all that is needed.
Medicine cannot cure the valve, but some types of medicine (digitalis, diuretics, anticoagulants, beta blockers, calcium channel blockers, and ACE inhibitors) may ease the pain or symptoms, reduce the workload on the right ventricle, or regulate an associated arrhythmia.
If symptoms worsen, become difficult to manage, or if medicine no longer relieves symptoms, an intervention or open heart surgery may be needed. The mitral valve can be repaired or replaced. Most cardiovascular surgeons agree that repair is the preferred treatment for mitral valve disease. Repair may involve reinforcing the valve with an annuloplasty, sewing torn leaflets, shortening elongated muscle structures, or otherwise reconstructing the valve’s anatomy to restore normal function.
Mitral valve replacement is performed when a mitral valve cannot be repaired. It involves removing the defective valve and replacing it with a prosthetic valve. Prosthetic valves can be biological (made from human or animal tissue) or mechanical (made from materials such as plastic, carbon, or metal). Mechanical valves carry the risk of blood clot formation on the new valve, so patients with mechanical heart valves must take blood-thinning medicine for the rest of their lives to prevent this complication.
Preventative Antibiotics and Heart Valve Disease
Patients with heart valve disease who have an abnormal heart or who’ve had heart surgery risk developing endocarditis. The American Heart Association no longer recommends taking routine antibiotics before certain dental or surgical procedures except for people at the highest risk for bad outcomes if they do develop endocarditis.
Texas Heart Institute www.texasheartinstitute.com/HIC/Topics/Cond/valvedis.cfm
Texas Heart Institute www.texasheartinstitute.com/HIC/Topics/Cond/vmitral.cfm
Mayo Clinic www.mayoclinic.org/heart-valve-disease/index.html
American Heart Association www.americanheart.org/presenter.jhtml?identifier=3057274