What is mitral valve regurgitation?
Mitral valve regurgitation, or simply mitral regurgitation, is a heart valve malfunction and disorder that affects the mitral valve.
The most prevalent type of heart valve disease, it occurs when the mitral valve does not shut properly during the cardiac cycle due to a physical abnormality. This allows blood to leak back (regurgitate) into the left atrium.
Mitral regurgitation is sometimes described as mitral incompetence or mitral insufficiency because the mitral valve incompetently or insufficiently performs its core functions in the heart. One can therefore also ask what is mitral incompetence or what is mitral insufficiency.
What happens in people with mitral regurgitation?
As a consequence of the damage or abnormality, when the heart beats and the mitral valve closes after blood has passed through it, the valve does not form a tight seal, allowing blood to trickle back into the left atrial chamber to some degree. This often causes symptoms and complications.
Are there different types of mitral valve regurgitation?
Mitral regurgitation is medically classified as either primary or secondary. Primary (organic) mitral regurgitation is regurgitation that occurs due to a problem with the valve. Secondary (functional or ischemic) regurgitation occurs due to dysfunction of the left ventricle.
With secondary regurgitation, the left ventricle normally dilates due to dilated cardiomyopathy. This causes the mitral annulus to stretch and the papillary muscles to move out of place.
Is mitral regurgitation a progressive disease?
Yes. There are three clinical phases, namely acute, chronic compensated, and chronic decompensated.
Acute mitral regurgitation – usually the result of one or more ruptured chordae tendinae or papillary muscles – tends to occur suddenly. It causes a volume and pressure overload in the left ventricle and atrium, which may hinder blood drainage from the lungs and cause pulmonary congestion.
If regurgitation develops slowly, or if acute regurgitation cannot be controlled with treatment, then the patient enters the chronic compensated phase. Here, the left ventricle and atrium enlarge as a compensation response, improving cardiac output and relieving pulmonary congestion.
Though the compensated phase may persist, patients eventually enter the chronic decompensated phase, where the left ventricle and mitral annulus dilate and pulmonary congestion reoccurs. The degree of regurgitation generally worsens and the patient experiences heart failure symptoms.
What are the symptoms of mitral valve regurgitation?
Mitral regurgitation symptoms vary, depending on the phase and individual.
Patients in the acute phase typically experience symptoms such as dyspnea (shortness of breath), paroxysmal nocturnal dyspnea (severe dyspnea attacks at night), orthopnea (dyspnea when lying flat), and heart palpitations. Cardiogenic shock can occur if chordae or papillary muscles rupture.
People in the chronic compensated phase often do not experience symptoms at all. They are able to exercise normally and perform physical tasks as a healthy person would.
In the chronic decompensated phase, which can take years, the patient may experience exercise intolerance, dyspnea, and orthopnea, atrial fibrillation, palpitations, angina, fatigue, and/or syncope.
A heart murmur can normally be heard if one has mitral valve regurgitation.
What causes mitral regurgitation?
Other causes include ischemic heart disease, heart attacks, and rheumatic fever, as well as Marfan’s Syndrome. There also appears to be a connection between mitral regurgitation and diseases like Ehlers Danlos Syndrome, Down Syndrome, and Osteogenesis Imperfecta.
Secondary mitral valve regurgitation may be caused by non-ischemic dilated cardiomyopathy, non-compaction cardiomyopathy, and aortic regurgitation.
In acute cases of regurgitation, infective endocarditis is often the cause.
Risk factors for the condition in general include inflammatory diseases such as rheumatoid arthritis and lupus, radiation exposure, and old age, malnutrition, alcoholism, and drugs like lithium, phenothiazines, and sulphonamides, and chemotherapy drugs.
How is mitral valve regurgitation diagnosed?
Mitral regurgitation can be diagnosed once a physician studies a patient’s medical history, performs a thorough physical examination, and listens for a heart murmur with a stethoscope. Other tests may also be performed to confirm the diagnosis and determine the degree of regurgitation.
Transthoracic echocardiography is the standard testing method for mitral valve regurgitation, but diagnostic tests may also include a transesophagealan echocardiogram, an electrocardiogram (EKG), holter monitor testing, event monitor testing, exercise stress testing, and/or chest x-rays.
Magnetic resonance imaging, computed tomography, and cardiac catheterization are other reliable testing methods that are used to detect and evaluate this heart valve disease.
How is mitral regurgitation treated?
There are two main treatment options for mitral valve regurgitation are medication and surgery. Whether or not a person requires treatment depends on the severity of the symptoms and the cause of the regurgitation, as well as the presence of any underlying medical disorders.
Medications used to treat mitral regurgitation include vasodilators like ACE inhibitors and hydralazine, anticoagulants like aspirin or warfarin, and diuretics such as furosemide and indapamide. Other drugs include digoxin, antiarrhythmics like beta blockers, and antibiotic prophylaxis.
Surgery, which is the preferred treatment for severe regurgitation, involves repairing or replacing the mitral valve and its structures. Surgical treatment, unlike medication, is curative and can be invasive or minimally invasive. Not everyone is a suitable candidate, however.
Many times, both medication and surgery are required to treat the condition.
What is the prognosis for patients with mitral valve regurgitation?
The prognosis with this condition depends on the degree of displacement, the extent of the regurgitation or regurgitant fraction, and how the disease progresses naturally. Individual risk factors and underlying conditions also determine the outcome and manageability.
Complications like edema, atrial fibrillation, heart failure, infective endocarditis and blood clotting, as well as any troublesome symptoms, are more common in those with severe regurgitation. Nevertheless, asymptomatic patients with mild forms of the disease often deteriorate over time.
Medications can relieve symptoms and prevent complications, but only surgery can remedy the problem. While there are risks involved and not every patient can undergo surgery (i.e., the sick, the elderly), surgical treatment for mitral regurgitation does have a high success rate.