Mathematical analysis of the sphygmogram
Abstract
Diagnosis of the functional state of the cardiovascular system occupies one of the main places in medicine. A clear and accessible method for analyzing the state of the cardiovascular system is sphygmography - an instrumental method for studying the arterial pulse, based on recording the widening of the artery during the passage of the pulse wave along it.
Analysis of the sphygmogram includes a time analysis of individual elements of the sphygmogram and a description of the shape of the curve, which is very common in certain diseases.
With the help of a pair of LED-photodiode, a signal of a sphygmogram was obtained, which along with the electrocardiogram signals and cardiointervalograms gives information about the physical state of the object under study and its biological age.
A computer method for processing sphygmogram signals based on measuring the geometric characteristics of the pulse was used to obtain information on the state of the cardiovascular system of two people.
A pulse wave of the 1st type, recorded on the upper limb in young people, is characterized by a rapid ascent, a rather sharp peak and the presence of one or more additional maxima on the descending part of the curve. The time interval between the straight line and the reflected wave is 0.3-0.4 s, the amplitude of the reflected wave is less than 50% of the amplitude of the direct wave.
In older people, the curve of the sphygmogram is characterized by a slow rise with a rounded apex (pulse wave of the 2th type) and an arcuate shape of the apex (pulse wave of the 3th type). On the descending part of the sphygmogram, a dither or no dicrotic wave is observed. Its maximum is located in the upper or middle part of the curve, whereas in young people (pulse wave type 1) - usually in the lower third. In a pulse wave of the 4th type, the reflected wave practically merges with the straight wave because of the great stiffness of the aortic walls.
Advantages of the method is the simplicity of its hardware support and the mathematical processing with a large volume of information received.
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References
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