Diagnosis - Valvular Heart Disease

The heart has four valves: mitral and aortic (located on the left side of the heart), tricuspid and pulmonary (located on the right side of the heart). Normal functioning of the valves is extremely important to the heart's efficiency. These delicate structures allow for the efficient flow of blood progressively forward through the heart's chambers, maximizing the efficiency of the heart muscle's work. When valves become diseased, they may obstruct the flow of blood (known as "stenosis") or become leaky (called "regurgitation" or "insufficiency").

What Causes Valvular Heart Disease?
Valve disease can develop before birth (congenital) or can be acquired sometime during one's lifetime. Occasionally, the cause of valve disease is unknown.

Congenital valve disease most often affects the aortic or pulmonary valve. Valves may be the wrong size, have malformed leaflets, or have leaflets that are not attached correctly.

Acquired valve disease includes problems that develop with valves that were once normal. These may involve changes in the structure of the valve due to a variety of diseases or infections, including rheumatic fever or endocarditis. Other causes of acquired valve disease include coronary artery disease (e.g. previous heart attack), cardiomyopathy (heart muscle disease), high blood pressure, aortic aneurysms, and connective tissue diseases. Less common causes of valve disease include tumours, some types of drugs and radiation.

The next section will focus on conditions affecting the aortic and mitral valves.

Aortic Valve Stenosis and Regurgitation (diagnosis)
What does this mean?

The aortic valve lets blood flow from the heart's left ventricle (main pumping chamber of the heart) into the aorta (the main vessel which distributes oxygen-rich blood throughout the body.) The aortic valve closes after each heartbeat, to keep blood from leaking back into the left ventricle. A normal aortic valve has three leaflets or cusps. Aortic valves which have two leaflets are called bicuspid which is an abnormality from birth. Only about 2 percent of the population have biscuspid valves. Most bicuspid valves work normally for a long time — sometimes a lifetime. But some can become thickened and narrowed (stenotic) or leaky (regurgitant).

Mitral valve disease
The mitral valve is on the left side of the heart and it separates the left atrium from the left ventricle. It may become too narrow (stenosis) or leaky (regurgitation). Mitral stenosis is caused by rheumatic fever which is now rare. Mitral regurgitation can also be caused by rheumatic fever but there are other causes too. Diseases of the left ventricle may affect the valve by damaging the papillary muscles or altering the valve structure. Coronary artery disease (due to hardening of the arteries) may do this by causing a heart attack (or myocardial infarction). Heart muscle disease (cardiomyopathy) can do the same. The cusps and chordae may deteriorate. This is called mitral valve prolapse. This usually occurs alone, but may be part of a rare condition called Marfan’s syndrome where there are also abnormalities of other parts of the body. Infection on an abnormal mitral valve leads to a disease called infective endocarditis, and can occur even if the valve abnormality is minor. This usually causes a worsening of any previously leaking valve.

Endocarditis
If bacteria get into the bloodstream there is a risk of getting infection on an abnormal valve. This is called infective endocarditis and it can happen even if the valve defect is minor. Bacteria can get into the blood through the gums after dental treatment or with other operations or investigations which use instruments passed inside the body. Prevention, by taking antibiotics, is better than cure. They are given, usually by mouth, an hour before dentistry or an operation. You should carry a card with all the details. Show it to any doctor or dentist treating you.