In this study, ECG signals of normal sinus rhythm (NSR), ventricular tachycardia (VT) and ventricular fibrillation (VF) were taken out to extract the RR interval series. Approximate entropy (ApEn) values of the RR interval series were calculated and compared among the three groups by ANOVA methods. It was found that the values of ApEn were increased significantly from NSR to VT and then to VF. Approximate entropy may be regarded as an index to discriminate the ECG signals of different state.
Electrocardiography ; methods ; Entropy ; Humans ; Signal Processing, Computer-Assisted

After the current situation of knowledge service in aviation medicine was analyzed, the major problems in restrict security systems, few information access approaches, and difficulties in team construction for the knowledge service in aviation medicine were pointed out, with measures that should be taken in knowledge service put for-ward, such as keeping abreast of the key task in research of aviation medicine, making use of open access re-sources, digitalizing paper-type resources, organizing and revealing the knowledge in resources by making use of information technologies.