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the child had a narrow valve that might need surgery. Nowadays, such chil-

dren are usually referred to a cardiologist early on; the family can see the

valve on the echo tape and discuss with the cardiologist how severe the nar-rowing is and whether and how often follow-up will be necessary.

In earlier years, a condition such as aortic valve stenosiswhich is more

frequent in boys than in girlspresented a great problem, especially for

children eager to go out for sports; it was known that the narrowing of the

valve became more severe over time, but there was no good way of moni-

toring the change other than by repeated catheter tests. Now the severity of

the narrowing can be accurately assessed with the echo-Doppler, and if it is

not severe, unnecessary restrictions on a childs activity can be avoided. Oc-casionally, in about one in twenty children who have aortic valve stenosis,

the valve is severely narrowed and badly formed. Such a baby will have a

heart murmur, will be breathing fast, and will be restless and irritable; fluid

is accumulating in the lungs,often leading to wheezing and difficulty in feed-

ing. Emergency surgery will be necessary in the first days or weeks of life.

If the aortic valve is thickened there is a drop in pressure, also called a

gradient,between the left ventricle and the aorta. This gradient can be mea-

sured accurately with the Doppler test; such measurement allows an under-

standing of how severe the obstruction is and provides a way of monitor-

ing its progression over time. When the aortic valve is greatly thickened, with

a narrow opening, the left ventricular pressure may be between and

when pressure in the aorta is around . Maintaining a higher than normal

pressure is a strain on the left ventricle. The muscle of the ventricle, the myo-

cardium, thickens in order to maintain the needed pressure. This thicken-

ing (hypertrophy) is well tolerated if it is mild, but if the myocardium be-

comes greatly thickened, the blood supply from the coronary arteries to the

muscle becomes inadequate, particularly during strenuous exercise. In gen-

eral, a cardiologist will follow a child with aortic valve stenosis and recom-

mend treatment if the pressure is . times greater (or more) in the left ven-

tricle than in the aorta (for example, mm Hg in the ventricle, mm

Hg in the aorta).

The child with aortic valve stenosis will not need any medication other

than BE prophylaxis but will usually need to be checked annually during the

childhood years of rapid growth to make sure that the opening in the valve

is growing and keeping up with the needs of the growing body. Checkups

should continue throughout life, because problems may arise in middle age

or later years.

94 Heart Problems in Children