OBJECTIVE:To show that the pulse diagnosis used in Traditional Chinese Medicine,combined with nonlinear dynamic analysis,can help identify cardiovascular diseases.METHODS:Recurrence quantification analysis(RQA) was used to study pulse morphological changes in 37 inpatients with coronary heart disease(CHD) and 37 normal subjects(controls).An independent sample t-test detected significant differences in RQA measures of their pulses.A support vector machine(SVM) classified the groups according to their RQA measures.Classic time-domain parameters were used for comparison.RESULTS:RQA measures can be divided into two groups.One group of measures [ecurrence rate(RR),determinism(DEL),average diagonal line length(L),maximum length of diagonal structures(Lmax),Shannon entropy of the frequency distribution of diagonal line lengths(ENTR),laminarity(LAM),average length of vertical structures(TT),maximum length of vertical structures(Vmax)] showed significantly higher values for patients with CHD than for normal subjects(P