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HRV Frequency-Domain Analysis

Source: R/ecg-hrv-freq.R
ecgHRVfreq.Rd

Computes heart rate variability frequency-domain metrics from RR interval data using Welch's method or Lomb-Scargle periodogram.

Usage

ecgHRVfreq(
  rr,
  method = c("welch", "lomb", "ar"),
  vlf_band = c(0.003, 0.04),
  lf_band = c(0.04, 0.15),
  hf_band = c(0.15, 0.4),
  detrend = FALSE,
  detrend_lambda = 500,
  ar_order = NULL,
  rhythm_check = TRUE
)

Arguments

rr

A data.frame with columns channel, rr_ms, and time_sec, as returned by ecgRRintervals.

method

Spectral estimation method: "welch" (default) for uniformly resampled FFT-based PSD, "lomb" for Lomb-Scargle periodogram on unevenly sampled data, or "ar" for a Burg autoregressive PSD.

vlf_band

Numeric vector of length 2 defining VLF band in Hz (default: c(0.003, 0.04)).

lf_band

Numeric vector of length 2 defining LF band in Hz (default: c(0.04, 0.15)).

hf_band

Numeric vector of length 2 defining HF band in Hz (default: c(0.15, 0.4)).

detrend

Logical; if TRUE, apply smoothness-priors detrending (smoothnessPriorsDetrend) to the resampled tachogram before spectral estimation (Welch method). Default FALSE (mean removal).

detrend_lambda

Smoothing parameter passed to smoothnessPriorsDetrend when detrend = TRUE (default 500).

ar_order

Integer AR model order for method = "ar"; NULL (default) selects the order automatically by AIC.

rhythm_check

Logical; if TRUE (default), gate the result on ecgDetectAF: metrics for channels classified as AF or frequent ectopy are set to NA and rhythm/hrv_valid columns are appended (HRV is undefined in atrial fibrillation).

Value

A data.frame with one row per channel and the following columns:

channel

Integer channel index.

vlf

Absolute power in the very-low-frequency band (ms^2).

lf

Absolute power in the low-frequency band (ms^2), associated with sympathetic and parasympathetic modulation.

hf

Absolute power in the high-frequency band (ms^2), associated with parasympathetic (vagal) modulation.

lf_hf_ratio

Ratio of LF to HF power, or NA if HF power is zero.

total_power

Sum of VLF, LF, and HF power (ms^2).

lf_nu, hf_nu

LF and HF power in normalized units, 100 * LF/(LF+HF) and 100 * HF/(LF+HF); these sum to 100.

lf_peak, hf_peak

Frequency (Hz) of the spectral peak within the LF and HF bands, or NA if the band is empty.

References

Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996). "Heart rate variability: Standards of measurement, physiological interpretation and clinical use." Circulation, 93(5), 1043–1065.

See also

ecgRRintervals for computing RR intervals, ecgHRVtime for time-domain HRV metrics, ecgHRVnonlinear for nonlinear HRV analysis, ecgRRcorrect for ectopic beat correction before analysis.

Examples

n <- 300
time_sec <- cumsum(rep(0.85, n))
rr_ms <- 850 + 30 * sin(2 * pi * 0.1 * time_sec)
rr <- data.frame(channel = rep(1L, n), rr_ms = rr_ms, time_sec = time_sec)
result <- ecgHRVfreq(rr, method = "welch")