Research On The Mutual Correlation Between Modes Of Pulse Signals From Carotid And Wrist Arteries

The research on the modes of the artery pulse is carried on in this thesis. The synchronous pulse signals from carotid and wrist arteries are collected by a multi-channel pulse signal collect system, and then the HHT (Hilbert-Huang Transformation) method is adopted to decompose the modes of these two sets of signals to various orders of magnitude. The pulse signals are collected not only by age-groups, the healthy youth, healthy middle-aged and healthy aged, but also from those patients with coronary artery disease before and after operations.Further more, the mutual correlation method is introduced to analyze cross correlation of each mode couple in pulse signals collected from carotid and wrist arteries. These mutual correlation characteristic curves of each pulse mode in terms of healthy people and those patients with coronary artery disease are also obtained. They indicate that the pulse signals produced from the heart reach to the carotid earlier than to the wrist. The comparison of the pulse phases between different age groups could reveal that in the blood vessel hardness, the healthy youth < the healthy aged≤those patients with coronary artery disease.The investigation shows that these pulse modes of the first order from the carotid and wrist arteries are very similar to that of the x-wave pattern, which indicate that this signal is out of the heart, and it can transmit along blood vessels without obvious damping in some conditions. For those healthy people, each mode couple of the first order from different pulse signals is similar to the x-wave pattern by the mutual correlation analysis; that of the second order is of one third of the pulse period, and that of third order is of one half of the pulse period. The fourth-order modes are of the same period as the original pulse signal.The patterns of carotid and wrist artery pulses from those patients with the coronary artery disease before and after operation are also determined, respectively. The mutual correlation characteristics reveal that those of the first-order mode change distinctly. In the group of healthy people, there is a long flat branch of mutual correlation curves whose values approach to zero, whereas the corresponding curves for the patients are irregular. The mutual correlation curves for those modes of other orders show a few differences between the healthy people and patients, which indicate that these modes of the healthy people have less relationship with those suffering from the coronary artery disease. The investigation also shows that after operation, the first-order pulse modes of those patients suffering the coronary artery disease have been improved remarkably.