Mitral Valve Regurgitation: Diagnosing the Condition

Mitral regurgitation is a condition in which disease or injury has caused the heart's mitral valve to leak. The four heart valves function as one-way valves, allowing blood to be pumped forward and preventing blood from regurgitating backwards. When the mitral valve becomes defective, blood may regurgitate into the lungs, causing shortness of breath. An untreated valve can lead to heart failure.

Because some of the blood being pumped by the left ventricle regurgitates into the left atrium, less blood is pumped into the aorta and, ultimately, throughout the body. The heart compensates for this by increasing the size of the left ventricle to increase the amount of blood it is pumping and to maintain an adequate forward flow of blood throughout the body. Unfortunately, compensation eventually leads to impairment of the left ventricle's ability to contract which will lead to fluid accumulation into the lung.

In patients with mitral regurgitation, the lungs become congested with fluid. As fluid accumulates in the lungs, it interferes with the absorption of oxygen from the lungs into the bloodstream. This leads to shortness of breath. Some patients feel short of breath when they exercise or exert themselves. Some patients feel short of breath when they lie down at night. They may need to sleep with their heads elevated to avoid waking up in the middle of the night feeling short of breath. As the heart dilates (enlarges) and, eventually, decompensates, other symptoms of heart failure develop. Patients may fatigue easily and feel weak; others may also notice swelling in their ankles and feet due to accumulation of fluid in these areas

Physical examination with chest auscultation often will reveal a heart murmur. An echocardiogram can be an invaluable tool in diagnosis. The echocardiogram uses sound waves to image the mitral valve and the chambers of the heart. It can also be used to image and assess the amount of blood regurgitating from the left ventricle back into the left atrium.

Following a physical examination and cardiac echo, uncertainty about the causes for mitral regurgitation may require that a patient be referred for a cardiac catheterization During cardiac catheterization, ventriculograms are taken to see how well the left ventricle is pumping blood into the aorta and to see the amount of blood that regurgitates across the defective mitral valve back into the left atrium.

The amount of mitral regurgitation is then semiquantitatively assessed and is rated as mild, moderate of severe. During the cardiac catheterization, images of the coronary arteries also are obtained to find out if there are partial or total blockages of one or more of the coronary arteries. Blockages may lead to dysfunction of the mitral valve and to mitral regurgitation.

Recently, the American Heart Association has released new guidelines for premedication of patients with mitral valve regurgitation undergoing dental therapy. The new guidelines suggest that patients with mitral regurgitation do not have to premedicate prior to dental procedures. Although these recommendations have been made, most dental practitioners will still request a formal consultation and evaluation from the patient's cardiologist in regards to premedication for dental procedures. It is highly recommended that all patients with any cardiac condition strictly follow the recommendations of their physician prior to any dental procedure.