|
 What
are heart valves?
Heart valves are like any other valves one comes across in
household directing fluid movement from one area to the other.
There are 4 valves in the heart (Figure). Mitral valve and
tricuspid valve govern the blood flow from the upper chambers
(atria) to lower chambers (ventricles). They allow the blood
only to go into the ventricles. Pulmonary valve and aortic valve
are located at the exits of two ventricles and they allow the
blood only to go out i.e. from the heart to the large conduits
called arteries. These valves open and close in various phases
of cardiac activity to make sure that blood flows only in one
direction through the heart.
What happens when a valve is diseased?
A valve has two functions: It opens to allow
the blood to pass and shuts to prevent back flow of blood. If it
does not open well, it will obstruct the flow of blood and is
‘valve stenosis’. If it does not close well, the blood leaks
back to the chamber from which it was ejected. This is called
‘valve regurgitation’.
How does it affect the heart?
If the valve does not open well, heart has to
generate additional force to pump the blood across the valve. If
the valve does not close well, heart has to handle the
additional blood that is leaking back. Generally valve diseases
progress relatively slow allowing the heart to compensate to
some extent at least initially.
What are the causes of valvular problems?
The most common cause in our country is that
which occurs secondary to rheumatic fever. Other causes are:
being born with diseased valve, some congenital heart defects
with associated valve disease, mitral valve prolapse, following
heart attack, age related changes in the valves, infection of
the valve (endocarditis) etc.
What are the symptoms of valvular heart
diseases?
Usual symptoms are getting tired easily,
palpitations, breathlessness on exertion, chest pain and in
some, dizziness and fainting. In advanced stage, swelling of
ankles, legs and face can occur. When the disease is mild or
moderate, it causes minimal or no symptoms. At times, patients
may remain well even with a severely diseased valve due to
compensatory mechanisms. However, there would be ongoing damage
to the heart and lungs. These are the unlucky patients who might
present to the doctor in a late stage beyond the stage of
suitability for surgery. As there is no clear correlation
between the symptom and the degree of underlying disease, one
should not postpone the treatment.
How is this condition diagnosed?
The doctor detects the murmur at the chest.
He can find features of enlarged heart chambers. ECG and chest X
ray would give further clues and usually, an echo cardiogram is
needed for complete evaluation of the valve disease. At times,
patients would be asked to do treadmill exercise test to assess
the exercise tolerance. This test can bring out the symptoms in
a patient who claims to have no symptom.
Should everyone undergo treatment once a
valve disease is identified?
No. Depending on the nature of the disease,
the doctor would decide the treatment plan. In many patients
with mild problem, the disease would remain mild for long years.
At times, it can worsen fast. Even those with severe disease,
not everyone would need immediate surgery. Generally,
cardiologists decide the exact timing of intervention which
could be transcatheter or surgical intervention. This would be
either based on the symptoms or the changes occurring in the
heart as assessed by clinical evaluation and echocardiography.
Hence, it is important for the patient to have regular medical
checks with the doctor, even if there are no symptoms.
What is the treatment for valvular heart
diseases?
It could be medical therapy, cardiac surgery
or transcatheter interventions. These would be discussed
subsequently under specific valve conditions.
Dr
Jawahar Kannan
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