Faculty Scholarly Dissemination Grants


Frequency Domain Analysis of Heart Rate Variability using Interpolation and Resampling


School of Engineering


Padnos College of Engineering and Computing

Date Range



Conventional frequency domain analysis of heart rate variability (HRV) in vivo uses tachograms computed as interbeat interval vs. beat number. Inferences drawn from this analysis are flawed since it ignores the effects of non-uniform sampling. We compared the conventional technique (interbeat interval vs. beat number, CT) to a novel technique (interbeat interval vs. time of occurrence of beat, NT) for the frequency domain analysis of HRV. Guinea pig hearts (n=6) were perfused at a constant pressure of 55mmHg with Kreb's-Ringers (KR, 37oC) solution. After 30min baseline (BL) stabilization, hearts were subjected to 30min global ischemia and 120min reperfusion (REP). Bipolar electrograms were recorded from the right ventricle for 4 min each at BL, and after 0min (REP00), 60min (REP60), and 120min (REP120) of REP. Tachograms were computed using CT and NT. For CT the estimated sampling frequency (fs)=1Hz and for NT tachograms were interpolated to fs=40Hz. We computed: a)total power (TP, 0.04-0.4Hz for CT and 0.12-16Hz for NT), b)ratio of power in low frequency (0.04-0.15Hz for CT and 1.6 to 6Hz for NT)to high frequency (0.15-0.4 for CT and 6 to 16Hz for NT) (LF/HF). Results showed: i)during REP00, TP increased more with NT than CT, ii)LF/HF showed no change after REP with CT. Conversely, as noted in vivo, LF/HF decreased after REP with NT. In conclusion, frequency domain analysis of HRV using NT, and not CT, were comparable to in vivo results emphasizing the need to correct for errors due to nonuniform sampling when analyzing HRV in the frequency domain.

Conference Name

2010 BMES Annual Meeting

Conference Location

Austin, TX

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