Cardiac rhythms in chick embryos during hatching

Hiroshi Tazawa, Hikaru Mitsubayashi, Masaji Hirata, Joachim Höchel, J. T. Pearson

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Avian embryos develop within a hard eggshell which permits the measurement of heart rate while maintaining an adequate gas exchange through the chorioallantoic membrane. Heart rate has been determined from cardiogenic signals detected either noninvasively, semi-invasively or invasively with various transducers. Firstly, we reviewed these previously-developed methods and experimental results on heart rate fluctuations in prenatal embryos. Secondly, we presented new findings on the development of heart rate fluctuations during the last stages of incubation, with emphasis on the perinatal period, which remained to be studied. Three patterns of acceleration of the instantaneous heart rate were unique to the external pipping period: irregular intermittent large accelerations, short-term repeated large accelerations and relatively long-lasting cyclic small accelerations. Besides these acceleration patterns, respiratory arrhythmia, which comprized oscillating patterns with a period of 1-1.5 s, appeared during the external pipping period. Furthermore, additional oscillating patterns with a period of 10-15 min were found in some externally pipped embryos.

Original languageEnglish
Pages (from-to)511-521
Number of pages11
JournalComparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology
Issue number4
Publication statusPublished - 1 Dec 1999
Externally publishedYes


  • Autonomic nervous system
  • Catheterization
  • Chick embryo
  • External pipping
  • Hatching
  • Heart rate fluctuations
  • Noninvasive determination
  • Perinatal period

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