Tests of Heart Strength

Disturbances of the Heart
by Oliver T. Osborne, M.D.

(Page 3 of 22)

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 cardio graphic 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 ergo meter 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 dioxide of the blood is increased in amount, which, stimulating the nervous centers controlling the suprarenal glands, increases the epinephrine 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 dioxide 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.