Mitral Regurgitation
Mitral Regurgitation | Mitral Valve Prolapse | Mitral Stenosis | Aortic Stenosis | Aortic Insufficiency |
Tricuspid Regurgitation | Endocarditis | Bicuspid Aortic Valve | Connective Tissue Disease
Tricuspid Regurgitation | Endocarditis | Bicuspid Aortic Valve | Connective Tissue Disease
What is Mitral Valve Regurgitation?
Mitral valve regurgitation (MR), also known as a leaking mitral valve, Barlow's syndrome, occurs when one or both of the flaps may not close properly, allowing the blood to leak backward (regurgitation). This regurgitation may result in a murmur (abnormal sound in the heart due to turbulent blood flow). Mitral regurgitation (backward flow of blood), if present at all, is generally mild.
What is the mitral valve?The mitral valve is located between the left atrium and the left ventricle and is composed of two flaps. Normally the flaps are held tightly closed during left ventricular contraction (systole) by the chordae tendineae (small tendon "cords" that connect the flaps to the muscles of the heart). In Mitral Valve Prolapse (MVP), the flaps enlarge and stretch inward toward the left atrium, sometimes "snapping" during systole, and may allow some backflow of blood into the left atrium (regurgitation).
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What are the causes of MR?
The most common cause of primary mitral regurgitation in the United States (causing about 50% of primary mitral regurgitation) is myxomatous degeneration of the valve. This causes a stretching out of the valve leaflets and the chordae tendineae. The elongation of the valve leaflets and the chordae tendineae prevent the valve leaflets from fully coapting when the valve is closed, causing the valve leaflets to prolapse into the left atrium, thereby causing mitral regurgitation.
Ischemic heart disease causes mitral regurgitation by the combination of ischemic dysfunction of the papillary muscles, and the dilatation of the left ventricle that is present in ischemic heart disease, with the subsequent displacement of the papillary muscles and the dilatation of the mitral valve annulus.
Rheumatic fever and connective tissue disease (e.g. Marfan's syndrome and Ehlers Danlos Syndrome) are other typical causes of mitral regurgitation.
Secondary mitral regurgitation is due to the dilatation of the left ventricle, causing stretching of the mitral valve annulus and displacement of the papillary muscles. This dilatation of the left ventricle can be due to any cause of dilated cardiomyopathy, including aortic insufficiency, nonischemic dilated cardiomyopathy and Noncompaction Cardiomyopathy. It is also called functional mitral regurgitation, because the papillary muscles, chordae, and valve leaflets are usually normal.
Acute mitral regurgitation is most often caused by infaction of the heart valve. Papillary muscle rupture or dysfunction, including mitral valve prolapse are also common causes in acute cases.
What are the symptoms of MR?
MR may not cause any symptoms. The following are the most common symptoms of MR. However, each individual may experience symptoms differently. Symptoms may vary depending on the degree of disease present and may include:
The symptoms of mitral valve prolapse may resemble other medical conditions or problems. Always consult your physician for a diagnosis.
- Palpitations - sensation of fast or irregular heart beat are the most common complaint among patients with MVP. The palpitations are usually associated premature ventricular contractions (the ventricles beat sooner than they should), but supraventricular rhythms (abnormal rhythms that begin above the ventricles) have also been detected. In rare cases, patients may experience palpitations without observed dysrhythmias (irregular heart rhythm).
- Chest pain associated with MVP is different from chest pain associated with coronary artery disease (feels different, has different trigger, and different period of duration) and is a frequent complaint. Usually the chest pain is not like classic angina, but can be recurrent and incapacitating.
- Depending on the severity of the leak into the left atrium during systole (mitral regurgitation), the left atrium and/or left ventricle may become enlarged, leading to symptoms of heart failure. These symptoms include weakness, fatigue, and shortness of breath.
The symptoms of mitral valve prolapse may resemble other medical conditions or problems. Always consult your physician for a diagnosis.
How is MR diagnosed?
Persons with MR often have no symptoms and detection of a murmur may be discovered during a routine examination.
MR may be detected by listening with a stethoscope revealing a a murmur. The murmur is caused by some of the blood leaking back into the left atrium.
In addition to a complete medical history and physical examination, diagnostic procedures for MR may include any, or a combination, of the following:
In some situations where symptoms are more severe, additional diagnostic procedures may be performed. Additional procedures may include:
MR may be detected by listening with a stethoscope revealing a a murmur. The murmur is caused by some of the blood leaking back into the left atrium.
In addition to a complete medical history and physical examination, diagnostic procedures for MR may include any, or a combination, of the following:
- electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
- echocardiogram (also called echo) - a noninvasive test that uses sound waves to produce a study of the motion of the heart's chambers and valves. The echo sound waves create an image on the monitor as an ultrasound transducer is passed over the heart. Echocardiography is the most useful diagnostic test for MVP.
In some situations where symptoms are more severe, additional diagnostic procedures may be performed. Additional procedures may include:
- stress test (also called treadmill or exercise ECG) - a test that is performed while a patient walks on a treadmill to monitor the heart during exercise. Breathing and blood pressure rates are also monitored.
- cardiac catheterization - with this procedure, x-rays are taken after a contrast agent is injected into an artery to locate the narrowing, occlusions, and other abnormalities of specific arteries. In addition, the function of the heart and the valves may be assessed.
- cardiac MRI - this is a noninvasive test that produces comprehensive images of the heart. It may be used as a complement to echo for a more precise look at the heart valves and heart muscle, or in preparation for heart valve surgery.