Valvular Heart Disease
Specific valvular lesions
The aortic valve is situated between the left ventricular which is the
main pumping chamber of the heart, and the aorta which is the big blood
vessel leading from the heart. This valve may become narrowed either on
a congenital or hereditary basis or on an acquired basis such as due to
rheumatic heart disease or calcific degeneration due to aging. When the
valve is narrowed or stenotic the left ventricle has to pump against a
higher pressure. This ultimately leads to thickening of the ventricle
and may over time lead to weakness of heart muscle.
The symptoms of aortic stenosis include chest pain, shortness of breath
and dizziness or fainting. If any of these symptoms occur, then surgical
replacement of the aortic valve is warranted. If there are no symptoms
then it is safe to follow the patient with periodic physical examination
and cardiac ultrasound. As with other patients with valvular heart disease
antibiotics are required under certain conditions to prevent infection
from occurring on the heart valve.
The aortic valve may leak or become regurgitant. This may be due to a
congenital or hereditary abnormality or may be acquired. The heart has
great capacity to deal with the leaking aortic valve. The heart may enlarge
considerably. At some point if the patient develops symptoms of shortness
of breath, or congestive heart failure then valve replacement would be
indicated. As well, it is necessary to follow patients with leaky aortic
valves periodically with clinical examination and cardiac ultrasound as
at a certain point it is necessary to replace the valve with or without
the presence of symptoms.
Mitral stenosis is a condition where the valve leading into the left ventricle
from the left atrium, that is into the main pumping chamber from the left
atrial filling chamber, becomes narrowed. This is usually due to rheumatic
heart disease. Symptoms of mitral stenosis include shortness of breath
and palpitations. Mitral stenosis develops slowly and it may be many years
before patients become symptomatic. When symptomatic it is possible to
do balloon valvuloplasty procedures to open the mitral valve non-surgically
using a catheter procedure. In some patients open surgery to repair or
replace the mitral valve is required.
All patients with mitral valve disease require anti-biotic prophylaxis.
Mitral regurgitation or leaking of the mitral valve results in a excess
volume overload of the left ventricle and left atrium. Both chambers enlarge.
The heart can cope for many years with a leaky mitral valve but may eventually
wear out. It is necessary to follow the patients with significant mitral
regurgitation closely to try and predict the timing of mitral valve repair
or replacement. In mitral regurgitation, if one waits to the point where
patients develop symptoms the left ventricle may be irreversibly damaged.
There are various causes of mitral regurgitation. The most common is a
condition called mitral valve prolapse, which is a hereditary condition
of thickening and elongation of the mitral valve. Mitral valve prolapse
may be present in very minor form or may be present in severe form with
significant leaking of the valve. All patients with mitral valve prolapse
and significant leaking of the mitral valve, or thickening of the mitral
valve, require antibiotics during dental work or other surgical procedures
to prevent infection from developing on the abnormal valvular structures.
The mitral valve may also become leaky due to rheumatic heart disease.
Sometimes the mitral valve is affected by enlargement of the heart due
to coronary heart disease or other causes of weakened heart muscle (cardiomyopathy).
These conditions may lead to leaking of the valve as well.