Disturbances of the Heart | Page 7

even a lowering of blood pressure from the ordinary
level. They all have increase in pulse rate. He quotes several authorities
as showing that during muscle work the carbon dioxid of the blood is
increased in amount, which, stimulating the nervous centers controlling
the suprarenal glands, increases the epinephrin content of the blood.
The consequence is contraction of the splanchnic blood vessels, with a
rise in general blood pressure. Also, the quickened action of the heart
increases the blood pressure. After a rest from the exercise, the extra
amount of carbon dioxid is eliminated from the blood, the suprarenal
glands decrease their activity, and the blood pressure falls.
Nicolai and Zuntz [Footnote: Nicolai anal Zuntz: Berl. klin. Wehnschr.,
May 4, 1914, p. 821.] have shown that with the first strain of heavy
work the heart increases in size, but it soon becomes normal, or even
smaller, as it more strenuously contracts, and the cavities of the heart

will be completely emptied at each systole. If the work is too heavy,
and the systolic blood pressure is rapidly increased, it may become so
great as to prevent the left ventricle from completely evacuating its
content. The heart then increases in size and may sooner or later
become strained; if this strain is severe, an acute dilatation may of
course occur, even in an otherwise well person. Such instances are not
infrequent. A heart which is already enlarged or slightly dilated and
insufficient, under the stress of muscular labor will more slowly
increase its forcefulness, and we have the delayed rise in systolic
pressure.
Barringer concludes that:
The pulse rate and the blood pressure reaction to graduated work is a
valid test of the heart's functional capacity. If the systolic pressure
reaches its greatest height not immediately after work, but from thirty
to 120 seconds later, or if the pressure immediately after work is lower
than the original level, that work, whatever its amount, has overtaxed
the heart's functional capacity and may be taken as an accurate measure
of the heart's sufficiency.
In another article, Barringer [Footnote: Barringer, T. B., Jr.: Studies of
the Heart's Functional Capacity as Estimated by the Circulatory
Reaction to Graduated Work, Arch. Int. Med., May, 1916, p. 670.]
advises the use of a 5-pound dumb-bell extended upward from the
shoulder for 2 feet. Each such extension represents 10 foot- pounds of
work, although the exertion of holding the dumb-bell during the
nonextension period is not estimated. He believes that if circulatory tire
is shown with less than 100 foot-pounds per minute exercise, other
signs of cardiac insufficiency will be in evidence. He also believes that
these foot-pound tests can be made to determine whether a patient
should be up and about, and also that such graded exercise will increase
the heart strength in cardiac insufficiency.
Schoonmaker, [Footnote: Schoonmaker: Am. Jour. Med. Sc., October,
1915, p. 582.] after studying the blood pressure of 127 patients,
concludes that myocardial efficiency will be shown by a comparison of
the systolic and diastolic blood pressure, with the patient lying down

and standing up, after walking a short distance. Such slight exercise
should not cause any subjective symptoms, either dyspnea, palpitation
or chest pain. If the heart muscle is in good condition, the systolic
pressure should remain the same after this slight exertion and these
changes in posture. When the heart is good, there may be slight
increased pressure when the patient is standing. If, after this slight
exercise in the erect posture, the systolic pressure is diminished, the
heart muscle is defective.
Martinet [Footnote: Martinet: Presse med., Jan. 20, 1916.] tests the
heart strength as follows: He counts the pulse until for two successive
minutes there is the same number of beats, first when the patient is
lying down, and then when he is standing. He also takes the systolic
and diastolic pressures at the same time. He then causes the person to
bend rapidly at the knees twenty times. The pulse rate and the blood
pressure are then taken each minute for from three to five minutes. The
person then reclines, and the pulse and pressure are again recorded,
Martinet says that an examination of these records in the form of a
chart gives a graphic demonstration of the heart strength. If the heart is
weak, there are likely to be asystoles, and tachycardia may occur, or a
lowered blood pressure.
Rehfisch [Footnote: Rehfisch: Berl. klin. Wehnsehr., Nov. 29, 1915]
states that when a healthy person takes even slight exercise, the aortic
closure becomes louder than the second pulmonic sound, showing an
increased systolic pressure. If the left ventricle is unable properly to
empty itself against the increased resistance ahead, the left auricle will
contain too much blood, and with the right ventricle sufficient, there
will be an accentuation of the second