16-04-2012, 01:24 PM
LOW-VOLTAGE ELECTROCARDIOGRAMS
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REVIEW OF THE LITERATURE
The literature on the subject is not' large. Almost
wxithout exception, tracings showing low-voltage changes
in all three leads have alone been considered. Sprague
and White1 analysed fifty-seven cases, all curves having
an excursion of not more than 5 mm. either side of the
base-linle. They found that the arteriosclerotic group was
the commonest (thirty-four cases), ten -of these -having
definite occlusion of the, coronary arteries. Ten cases
belonged to the hypothyroid group. The remaining
thirteen included three cases in which syphilitic infection
had been a' marked feature. Finally, it was definitely
stated that lo-w-voltage curves were not found with
normal hearts.
The First Type
Electrocardiograms taken during a period of two years
were examined. All cases in which the clinical history
and state of the patient were unknown were excluded
this reduced the number under consideration to 720. Of
thes'e, twenty showed low-voltage curves in all three
leads, and will be considered later. The remaining 700
tracings were divided into three groups, in which (A) the
cardiovascular system, after full examination, had been
passed as nor-mal (B)_ the electrocardiogram was normal
in all other respects, although the heart was affected
and © the heart was affected, the electrocardiogram
being abnormal in other respects.
Attendance.-
Loss of attendance during any part of the
school career was counted, and three classes of children
were included: (a) those going to school late; (b) those
changing school during their " primary " career; ©
" irregular attenders," in the commonly accepted sense.
In the third class it was found impossible to fix any
definite standard which would imply irregularity, and
reliance was placed on the teacher's estimate. It is, of
course, accepted that the greatest amount of irregularity
is bound to occur during the early years of the school
career, and the figures for the 9 years group show that
the position of the child in school suffers materially during
that period. By the time the child is 13 there has been
an opportunity to make up the lost ground, and the
irregular attenders are more evenly spread over the four
divisions, although the " normal " children still show
the smallest percentage of irregularity. The striking
factors are that there is greater irregularity among children
from very small houses and from large houses, and that
there is a larger percentage of irregular attenders among
girls than among boys, especially in the 9 years group.
Children of professional people are more irregular in
attendance than those of manual workers, and the children
of sedentary workers are the best attenders. It is evident,
therefore, that a child's position in school cannot be
taken alone as a reliable index of its mental capacity,
especially in the earlier years.