Showing papers by "Isaac Starr published in 1964"
TL;DR: Most measurements of the various aspects of cardiac function which can be expressed quantitatively, such as cardiac output, slope of ascending pulse-wave front and ballistocardiogram, indicate that cardiac function diminishes at a rate of between 0.5 to 2 per cent a year as age advances, but estimates of cardiac strength based on the classic method, the pulse amplitude, suggest that cardiac strength increases as age advancing.
Abstract: How best to express the strength of the heart or the effort which goes into its contraction presents a problem. Certainly “work” in the Newtonian sense is not the answer; and another solution, the tension-time, is suggested; its derivatives may also be required. Most measurements of the various aspects of cardiac function which can be expressed quantitatively, such as cardiac output, slope of ascending pulse-wave front and ballistocardiogram, indicate that cardiac function diminishes at a rate of between 0.5 to 2 per cent a year as age advances. There is an apparent exception to this rule, because estimates of cardiac strength based on the classic method, the pulse amplitude, suggest that cardiac strength increases as age advances. An explanation for this apparent discrepancy is advanced. In addition to diminishing in strength, there is an increased tendency for the heart's contraction to become more incoordinate as age advances.
4 citations
TL;DR: Greatly improved shin-bar ballistocardiograms can be secured by a simple technique in which the frequency of the movement of a body or its supports is increased.
1 citations