Instantaneous heart rate: should RR-intervals be resampled?

Area of Science:

• Cardiovascular Physiology
• Biomedical Signal Processing
• Time Series Analysis

Background:

• Heart rate variability (HRV) is commonly analyzed using RR-interval sequences (tachograms).
• Converting discrete tachograms to continuous instantaneous heart rate (IHR) time series often involves resampling.
• Existing resampling techniques may violate the inherent time-domain constraints of tachograms.

Purpose of the Study:

• To address the inconsistencies of traditional RR-interval resampling methods.
• To introduce a novel technique, frequency-modulated phase-interpolation (FMPI), for accurate IHR time series reconstruction.
• To evaluate the impact of FMPI on ECG signal synthesis and HRV spectral analysis.

Main Methods:

• Development and application of the frequency-modulated phase-interpolation (FMPI) technique.
• Synthesis of electrocardiogram (ECG) signals using FMPI.
• Comparison of FMPI with existing models like IPFM and the heart timing signal.
• Analysis of spectral characteristics of HRV derived from FMPI-reconstructed IHR.

Main Results:

• FMPI successfully preserves the time-domain constraints of tachograms during IHR reconstruction.
• FMPI enables the synthesis of ECG signals with accurate event-interval reconstruction.
• The study discusses FMPI's performance relative to IPFM and the heart timing signal.
• Reconstruction of IHR using FMPI offers new perspectives on spectral characterization of HRV.

Conclusions:

• Frequency-modulated phase-interpolation (FMPI) provides a more consistent method for converting tachograms to IHR time series.
• Accurate IHR reconstruction using FMPI is crucial for reliable HRV analysis, particularly spectral analysis.
• The developed technique has implications for improving the fidelity of physiological signal modeling and analysis.