What is mitral valve regurgitation?
Mitral regurgitation, sometimes called mitral incompetence or insufficiency, is a heart valve malfunction and disorder.
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, allowing blood to leak back (regurgitate) into the left atrium.
What happens in people with mitral regurgitation?
As a consequence, 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.
How is MR classified?
Mitral valve regurgitation is medically categorized as either primary or secondary. Primary (organic) mitral regurgitation is regurgitation that occurs due to a problem with the valve, while secondary (functional or ischaemic) MR occurs due to dysfunction of the left ventricle.
With secondary regurgitation, the left ventricle normally dilates due to dilated cardiomyopathy, causing the mitral annulus to stretch and the papillary muscles to move out of place.
Is mitral valve regurgitation a progressive disease?
Yes. There are three clinical phases: 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 and is a medical emergency.
If it develops slowly, however, or if it cannot be managed with treatment, then the patient enters the chronic compensated phase. In this phase, the left ventricle and atrium naturally enlarge as a compensation response, improving forward cardiac output and relieving pulmonary congestion and symptoms.
Eventually, the patient will enter the chronic decompensated phase, where the ventricle and mitral annulus dilate and pulmonary congestion reoccurs. The degree of regurgitation generally worsens and the patient experiences symptoms of congestive heart failure.
What are the symptoms of mitral regurgitation?
Symptoms may vary, depending on the phase and individual.
Patients in the acute phase typically experience heart failure 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 tendinae or papillary muscles rupture.
Patients in the chronic compensated phase often do not experience symptoms at all. They are able to exercise and perform physical tasks as a healthy person would. When the patient enters the chronic decompensated phase, which can take years, one may experience exercise intolerance, dyspnea, orthopnea, atrial fibrillation (abnormal heart rhythms), palpitations, angina, fatigue, and syncope (fainting). A heart murmur can normally be heard in MR patients.
What causes mitral valve regurgitation?
Mitral valve prolapse, which often results from myxomatous degeneration, is the number one cause of primary MR. Other causes include ischemic heart disease, heart attacks, rheumatic fever, and 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 MR, infective endocarditis is normally the cause. Risk factors for the condition in general include inflammatory diseases (rheumatoid arthritis/lupus), radiation exposure, old age, malnutrition, alcoholism, and certain drugs (lithium, phenothiazines, sulphonamides and chemotherapy drugs).
How is mitral 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 (caused by blood flowing back through the mitral valve) with a stethoscope during auscultation. Other tests may also be performed to confirm the diagnosis and determine the degree of regurgitation.
Transthoracic echocardiography is the standard testing method for MR, but diagnostic tests may also include a transesophagealan echocardiogram, and 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.
How is mitral valve regurgitation treated?
There are two main treatment options for mitral 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 MR 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 MR patients?
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 (the sick, the elderly, etc.), surgical treatment for mitral regurgitation does have a high success rate.