Tests Of Heart Strength


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Sources: Disturbances Of The Heart

If both systolic and diastolic blood pressure are taken, and the

heart strength is more or less accurately determined, mistakes in

the administration of cardiac drugs will be less frequent. Besides

mapping out the size of the heart by roentgenoscopy and studying the

contractions of the heart with the fluoroscope, and a detailed study

of sphygmographic and cardiographic tracings, which methods are not

available to the large majority of physicians, there are various

methods of approximately, at least, determining the strength of the

heart muscle.



Barringer [Footnote: Barringer, T. B., Jr.: The Circulatory Reaction

to Graduated Work as a Test of the Heart's Functional Capacity,

Arch. Int. Med., March, 1916, p. 363.] has experimented both with

normal persons and with patients who were suffering some cardiac

insufficiency. He used both the bicycle ergometer and dumb-bells,

and finds that there is a rise of systolic pressure after ordinary

work, but a delayed rise after very heavy work, in normal persons.

In patients with cardiac insufficiency he finds there is a delayed

rise in the systolic pressure after even slight exercise, and those

with marked cardiac insufficiency have 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 pulmonic sound and it may become louder than the second

aortic sound, showing a cardiac deficiency. If, on the other hand,

the right ventricle becomes insufficient, or is insufficient, the

second pulmonic sound is weaker than normal, and the prognosis is

bad.



Barach [Footnote: Barach: Am. Jour. Med. Sc., July, 1916, p. 84]

presents what he terms "the energy index of the circulatory system."

He has examined 742 normal persons, and found that the pressure

pulse was anywhere from 20 to 80 percent of the diastolic pressure

in 80 per cent of his cases, while the average of his figures gave a

ratio of 50 percent; but he does not believe that it holds true that

in a normal person the pressure pulse equals 50 percent of the

diastolic pressure. Barach does not believe we have, as yet, any

very accurate method of determining the cardiac strength or

circulatory capacity for work. He does not believe that the estimate

of the pressure pulse is indicative of cardiac strength. He believes

that the important factors in the estimation of the circulatory

strength are the systolic pressure, which shows the power of the

left ventricle, the diastolic pressure, which shows the

intravascular tension during diastole as well as the peripheral

resistance, and the pulse rate, which designates the number of times

the heart must contract during a minute to maintain the proper flow

of blood. He thinks that these three factors are constantly adapting

themselves to each other for the needs of the individual, and he

finds, for instance, that when the left ventricle is hypertrophied

and the output of blood is therefore greater, then the pulse will be

slowed. His method of estimation is as follows: For instance, with a

systolic pressure of 120 mm. and a diastolic pressure of 80 mm.,

each pulse beat will represent an energy equal to lifting 120 mm.

plus 80 mm., which equals 200 mm. of mercury, and with seventy-two

pulse beats the force would be 72 X 200, which equals 14,400 mm. of

mercury. He finds an average circulatory strength based on examining

250 normal individuals by the index, which he terms S, D, R

(systolic, diastolic rate), to be 20,000 mm. of mercury per minute.



Katzenstein [Footnote: Katzenstein: Deutsch. med. Wehnsehr., April

15, 1915.] finds, after ten years of experience, that the following

test of the heart strength is valuable: He records the blood

pressure and pulse, and then compresses the femoral artery at

Poupart's ligament on the two sides at once. He keeps this pressure

up for from two to two and one-half minutes, and then again takes

the blood pressure. With a sound heart the blood pressure will be

higher and the pulse slower than the previous record taken. If the

blood pressure and pulse beat are not changed, it shows that the

heart is not quite normal, but not actually incompetent. When the

blood pressure is lower and the pulse accelerated, he believes that

there is distinct functional disturbance of the heart and loss of

power, relatively to the change in pressure and the increase of the

pulse rate. He further believes that a heart showing this kind of

weakness should, if possible, not be subjected to general

anesthesia.



Stange [Footnote: Stange: Russk. Vrach, 1914, xiii. 72.] finds that

the cardiac power may be determined by a respiratory test as

follows: The patient should sit comfortably, and take a deep

inspiration; then he should be told to hold his breath, and the

physician compresses the patient's nostrils. As soon as the patient

indicates that he can hold his breath no longer, the number of

seconds is noted. A normal person should hold his breath from thirty

to forty seconds without much subsequent dyspnea, while a patient

with myocardial weakness can hold his breath only from ten to twenty

seconds, and then much temporary dyspnea will follow. Stange does

not find that pulmonary conditions, as tuberculosis, pleurisy or

bronchitis, interfere with this test.



Williamson [Footnote: Williamson: Ant. Jour. Med. Sc., April, 1915,

p. 492.] believes that we cannot determine the heart strength

accurately unless we have some method to note the exact position of

the diaphragm, and he has devised a method which he calls the

teleroentgen method. With this apparatus he finds that a normal

heart responds to exercise within its power by a diminution in size.

The same is true of a good compensating pathologic heart. He thinks

that a heart which does not so respond by reducing its size after

exercise has a damaged muscle, and compensation is more or less

impaired.



Practical conclusions to draw from the foregoing suggestions are:



1. An enlargement of the heart after exercise can be well shown only

by fluoroscopic examination, and then best by some accurate method

of measurement.



2. The blood pressure should be immediately increased by exercise,

and after such exercise should soon return to the normal before the

exercise. If it goes below the normal the heart is weak, or the

exercise was excessive.



3. The pulse rate should increase with exercise, but not

excessively, and should within a reasonable time return to normal.



4. The stethoscope will show whether or not the normal sounds of the

heart become relatively abnormal after exercise. If such was the

fact, though the abnormality was not permanent, heart insufficiency

is more or less in evidence.





5. The relation of pulse rate to blood pressure should always be

noted, and the working power of the heart may be estimated according

to Barach's suggestion.



6. The dumb-bell exercise tests suggested by Barringer (only, the

dumb-bells may be of lighter weight) are valuable to note the

gradual improvement in heart strength of patients under treatment.



7. The holding the breath test is very suggestive of heart

efficiency or weakness, but a series of tests must be made before

its limitations are proved.





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