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stage in the examination of a heart. The chest wall of a child is usually relatively
thin ; for this reason the rate and the rhythm (discussed above) are determined by
palpation, and also the position of maximum pulsation, the area of pulsation, the
furthest out point in the left fourth or fifth space at which pulsation is appreciable
(indicating indirectly the position of the left border of the left ventricle), the presence
or absence of the presystolic thrill of mitral stenosis, the systolic thrill of pulmonary
stenosis and the still more rare systolic thrill of aortic obstruction. Most important
of all, the type of thrust can be felt. The type of thrust gives the first and most
important indication of the thumping of fear, the deliberate thrust of hypertrophy
(the result of established disease) and the weak or the distressed forms of beat of
active carditis.
The thumping excited heart is nearly always felt over a wide area and mostly
outside the nipple line. The deliberate beat may be in or inside the nipple line in a
slight case, though usually in a low space, and is quite typical of hypertrophy. The
rheumatic carditis apex beat (apart from severe carditis, pericarditis, etc.) is well
outside the nipple line if the patient is standing, and is seen as an out-patient, and
the thrust is weak. As a result of exertion the beat may become distressed and
resemble the thumping anxious heart, but probably is felt further out (one inch
or more outside the nipple line in a child of eight years, for instance).
But it must be remembered that no one symptom or sign found at one examination
is pathognomonic of active carditis, unless the carditis is severe, and the child
obviously ill.
Rate of heart beat.—This is a very variable number in childhood. It is aSected
by exercise, posture, and excitement in health. The diseases which commonly
cause increased heart rate are anxiety—hysteria and rheumatic heart disease. In
the former case the heart may overact as part of a picture of obvious over-anxiousness,
or may be a specialised anxiety phenomenon in a child not apparently scared.
In the latter case the increased rate is, along with dilatation, the response of an
impaired heart muscle to work which is in health performed with a normal rate
and without dilatation. It is often difficult to distinguish between these two causes
of tachycardia, unless the patient can be watched during sleep, and the heart rate
during sleep can be counted. But it must be remembered that slow heart rate
during sleep does not exclude carditis. The character of apex thrust may help,
and this has been discussed in another paragraph.
Variations in rate.—In a child the heart does not beat at a steady rate, as in
most adults. Only in a phlegmatic child is the rate unaffected by the process of
being undressed and examined naked. As an idea of the possibility of being
admitted to the ward flits across the child's mind, the pulse rate may first thump
at a slow speed and then tear away at 120-130 per minute, before the face has shown
evidence of apprehensiveness. The idea of lying on a couch contains for many
children a suggestion of some imagined mutilating operation, usually quite unconsciously,
but sometimes reinforced by conscious memories of preparation for
tonsillectomy, dental extraction, circumcision, or some earlier experience which
has overtaken them when well and left them sore. When this is the case, the change
in heart rate on assumption of the supine posture is ludicrously unphysiological.
Another form of heart irregularity is sinus arrhythmia. Here the rate varies
with the respiratory cycle. The irregularity can be emphasised by exaggerated
but slow breathing. As is well known, this irregularity is of no significance in the
diagnosis of rheumatic carditis.
Premature contractions are clinically of two kinds. The constant ones, occurring
perhaps every second or third beat, only slightly influenced by exaggerated breathing,
have probably a physical basis in some localised fibrosis in the heart musculature.
The inconstant ones, influenced by deep respiration, heard in a group at the beginning
of the examination of a nervous girl's heart and then not recurring for several