RELATIONSHIP BETWEEN THE SENSITIVITY TO ISOPRENALINE AND THE APPROXIMATE ENTROPY OF R-R INTERVAL
心脏对异丙肾上腺素反应性与心搏间期近似熵的关系

In order to study the relationship between the sensitivity of heart to isoprenaline and the Approximate Entropy(ApEn) of heart rate variability, ApEn of RRI (RR interval) in different conditions were analyzed. The results showed that when atropine was used, the ApEn of RRI were decreased and that the responses to 0.2 μg/kg,0.4 μg/kg,0.6 μg/kg of isoprenaline were greater in normal condition than in condition atropine being used. The difference between them was statistically significant(P<0.05). When the effect of atropine partly disappeared, the response to isoprenaline recovered to some degree. It is concluded that the larger complexity of RRI, the greater response to isoprenaline. The hypothesis that nonperiodic firings in excitable cells, tissue or organ have greater sensitivity to stimuli than periodic firings activity does is further confirmed.