Browsing by Subject "Heart rate variability"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Model based and experimental investigation of respiratory effect on the HRV power spectrum
    (Institute of Physics Publishing Ltd., 2006) Yildiz, M.; Ider, Y. Z.
    The role of respiration in the genesis of heart rate variability (HRV) has been the subject matter of many experimental and modeling studies. It is widely accepted that the high frequency (HF) peak of a HRV power spectrum, which is centered at the average respiratory frequency, is caused by mechanisms activated by respiration. On the other hand, there is a debate on the possible role of respiration in the genesis of the low frequency (LF) peak which is usually centered around 0.1 Hz. In this study, a comprehensive cardiorespiratory interaction model is used to test various hypotheses regarding the role of respiration in the LF peak of HRV. In this model, chest and abdomen circumference signals and lung volume signal are used as respiratory inputs. Simulations are made for periodic, spontaneous and slightly irregular respiratory patterns, and it is observed that the more low frequency (LF) power there in the respiratory signals, the more LF power there in the model-predicted HRV. Experiments on nine volunteers are also performed for the same respiratory patterns and similar results are observed. Furthermore, the actual measured respiratory signals are input to the model and the model predicted and the actual HRVs are compared both in time domain and also with respect to their power spectra. It is concluded in general that respiration not only is the major contributor to the genesis of the HF peak in the HRV power spectrum, but also plays an important role in the genesis of its LF peak. Thus, the LF/HF ratio, which is used to assess sympathovagal balance, cannot be correctly utilized in the absence of simultaneous monitoring of respiration during an HRV test.
  • Thumbnail Image
    ItemOpen Access
    Model based and experimental investigation of the heart rate response to inspiratory hold
    (IEEE, 2007) Şengün, Esra; İder, Yusuf Ziya
    The goal of this study is experimental and model based investigation of the respiratory effect on Heart Rate Variability (HRV). In this study, the ECG and respiration were recorded from 6 healthy volunteers who were told to hold their breath for 30 seconds. 5 recordings were taken from each volunteer and signal averaging was used. It was observed that HRV changes with oscillatory behavior at around 0.1 Hz and returns approximately to the value before the beginning of breath hold. Moreover, by using the characteristics of actual respiratory signals. the HRV predicted by the UrsinoMagosso model was calculated. The actual HRV and the model predicted HRV were compared in time domain, and were found to be in concordance in general.