Objective: To explore the pathogenesis characteristics of variant angina pectoris (VAP) by extracting its syndrome elements and analyzing the combination and distribution regularity of the syndrome elements.Methods: One hundred and seventy-five case files of VAP patients were collected. The extraction of syndrome elements and symptom contribution to syndrome was completed by the partition method of complex system based on entropy theory. Diagnostic threshold was established by receiver operator characteristic curve. According to the results diagnosed by diagnostic criteria for syndrome element with quantitation, the combination and distribution regularity of the syndrome elements in patients with VAP was analyzed.Results: The basic syndrome elements in the patients with VAP were qi deficiency, qi stagnation, blood stasis, phlegm turbidity, phlegm-heat, stagnation-heat, yin deficiency and yang deficiency syndromes. It showed that the combination types of syndrome elements could be made up of one syndrome, two, three, four or more than four syndromes. Qi deficiency, yin deficiency, qi stagnation, blood stasis and phlegm turbidity syndromes had the higher frequency than other syndrome elements in the patients with VAP.Conclusion: The partition method of complex system based on entropy theory can be used in extracting the syndrome elements of the patients with VAP. It is found that VAP has complicated pathogenesis according to the combination and distribution regularity of syndrome elements. Qi deficiency, qi stagnation, blood stasis, phlegm turbidity and yin deficiency syndromes are the main syndrome elements.

Key words: angina pectoris, variant, syndrome, entropy, pathogenesis, TCM