Studies Made by Simulating Systole at Necropsy
XI. On the Higher Dynamic Functions of the Heart, and their Reflections in the Pulse Wave
The background of basic conceptions underlying this paper is familiar to everyone by experience. The powerful automobile, when the light turns from red to green, can make a "jack-rabbit start" which leaves the less powerful cars far behind. If the engine of the big car is weakened, as by a cylinder gone dead, it can still do 50 miles per hour on the parkway and get you to your destination, but the jack-rabbit start is no longer possible. The first sign of weakness manifests itself more conspicuously in differences in acceleration than in differences in speed or in the distance that can be traveled; indeed the effect on acceleration may be the only manifestation of weakness. There is every reason to expect that this analogy would hold for the cardiac performance also and that the first sign of a weakening myocardium might well manifest itself by a change in acceleration of the ejected blood. This paper is chiefly concerned with the development of a simple method, available to clinicians, which would aid in the detection of changes in the acceleration of the aortic blood. This opportunity has also been used to answer certain criticisms of our previously published work, some, we believe, due to misunderstanding of the mathematical background of statistical procedures, and others due to a frank difference of opinion concerning the accuracy of the Fick method used to test the results secured by one of our formulas published previously.
- © 1958 American Heart Association, Inc.