Real-time analysis of the heart rate variability during incremental exercise for the detection of the ventilatory threshold

Yasuyuki Shiraishi, Yoshinori Katsumata, Taketaro Sadahiro, Koichiro Azuma, Keitaro Akita, Sarasa Isobe, Fumiaki Yashima, Kazutaka Miyamoto, Takahiko Nishiyama, Yuichi Tamura, Takehiro Kimura, Nobuhiro Nishiyama, Yoshiyasu Aizawa, Keiichi Fukuda, Seiji Takatsuki

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Background--It has never been possible to immediately evaluate heart rate variability (HRV) during exercise. We aimed to visualize the real-time changes in the power spectrum of HRV during exercise and to investigate its relationship to the ventilatory threshold (VT). Methods and Results--Thirty healthy subjects (29.1±5.7 years of age) and 35 consecutive patients (59.0±13.2 years of age) with myocardial infarctions underwent cardiopulmonary exercise tests with an RAMP protocol ergometer. The HRV was continuously assessed with power spectral analyses using the maximum entropy method and projected on a screen without delay. During exercise, a significant decrease in the high frequency (HF) was followed by a drastic shift in the power spectrum of the HRV with a periodic augmentation in the low frequency/HF (L/H) and steady low HF. When the HRV threshold (HRVT) was defined as conversion from a predominant high frequency (HF) to a predominant low frequency/HF (L/H), the VO2 at the HRVT (HRVT-VO2) was substantially correlated with the VO2 at the lactate threshold and VT) in the healthy subjects (r=0.853 and 0.921, respectively). The mean difference between each threshold (0.65 mL/kg per minute for lactate threshold and HRVT, 0.53 mL/kg per minute for VT and HRVT) was nonsignificant (P > 0.05). Furthermore, the HRVT-VO2 was also correlated with the VT-VO2 in these myocardial infarction patients (r=0.867), and the mean difference was -0.72 mL/kg per minute and was nonsignificant (P > 0.05). Conclusions--A HRV analysis with our method enabled real-time visualization of the changes in the power spectrum during exercise. This can provide additional information for detecting the VT.

Original languageEnglish
Article numbere006612
JournalJournal of the American Heart Association
Volume7
Issue number1
DOIs
Publication statusPublished - 2018 Jan 1

Keywords

  • Cardiopulmonary exercise testing
  • Heart rate variability
  • Myocardial infarction
  • Real-time visualization
  • Ventilatory threshold

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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    Shiraishi, Y., Katsumata, Y., Sadahiro, T., Azuma, K., Akita, K., Isobe, S., Yashima, F., Miyamoto, K., Nishiyama, T., Tamura, Y., Kimura, T., Nishiyama, N., Aizawa, Y., Fukuda, K., & Takatsuki, S. (2018). Real-time analysis of the heart rate variability during incremental exercise for the detection of the ventilatory threshold. Journal of the American Heart Association, 7(1), [e006612]. https://doi.org/10.1161/JAHA.117.006612