Mitral Valve Disease
Obstructed, Leaky or Regurgitating Valves
The normally functioning heart pumps thousands of gallons of oxygen-rich blood through our bodies every day. Four one-way valves ensure the constant forward flow of blood through the four chambers of the heart. Thin leaflets or cusps (flaps) open and close in precisely timed movements, preventing leakage or insufficient flow.
When valves fail to open fully or close completely, the flow of blood may be obstructed (stenosis) or the blood may “leak” or flow backwards (regurgitation). Often these conditions occur together. Leaflets (flaps) may grow stiff or thickened or fuse together, or become torn or “floppy.” Valve disease may be caused by a variety of conditions. Many patients with valve disease may not experience symptoms early in the disease process, because the heart initially compensates by pumping harder. Symptoms, when they appear, include shortness of breath, fatigue,decreased exercise capacity, and arrhythmias (palpitations), and may lead to more serious conditions and possible death.
Mitral stenosis is a heart valve disorder that narrows or obstructs the mitral valve opening. Narrowing of the mitral valve prevents the valve from opening properly and obstructs the blood flow from the left atrium to the left ventricle. This can reduce the amount of blood that flows forward to the body. The main risk factor for mitral stenosis is a history of rheumatic fever but it may also be triggered by pregnancy or other stress on the body such as a respiratory infection, endocarditis, and other cardiac disorders.
Mitral Valve Prolapse
Mitral valve prolapse is a disorder in which, during the contraction phase of the heart, the mitral valve does not close properly. When the valve does not close properly it allows blood to backflow into the left atrium. Some symptoms can include palpitations, chest pain, difficulty breathing after exertion, fatigue, cough, and shortness of breath while lying down.
Functional Mitral Regurgitation
One other category of mitral valve disease is called functional mitral regurgitation, which is mitral valve insufficiency from an injured or failing heart. These cardiac conditions are referred to as cardiomyopathy and ischemic cardiomyopathy. Specific to these diseases, the mitral valve is normal, but the leaflet edges do not meet creating a large leak, because its supporting structures are pulled away and outward by the dilatation of the heart. These valves can be and should be repaired. In this case the ring placed around the base of the valve insertion in the heart is undersized and overly narrowed to achieve adequate coaptation of the leaflets. For the majority of patients with functional MR a valve repair is associated with better operative and long term results. Unlike valve repair for primary valve disorders the risks of surgery are greater and the long term results not as encouraging.