Detrended Fluctuation Analysis of RR Intervals

Performs detrended fluctuation analysis (DFA) on RR interval data to characterize fractal scaling properties. Computes alpha1 (short-range correlations, 4–16 beats) and alpha2 (long-range correlations, 16–64 beats).

Usage

ecgDFA(rr, short_range = c(4, 16), long_range = c(16, 64))

Arguments

rr

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

short_range

Numeric vector of length 2 defining the scale range (in beats) for alpha1 (default: c(4, 16)).

long_range

Numeric vector of length 2 defining the scale range (in beats) for alpha2 (default: c(16, 64)).

Value

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

channel

Integer channel index.

alpha1

Short-range scaling exponent. Values near 1.0 indicate fractal-like (healthy) correlations; values near 0.5 indicate uncorrelated (random) behavior; values near 1.5 suggest Brownian noise. NA if the series is too short.

alpha2

Long-range scaling exponent with the same interpretation as alpha1 but over larger time scales. NA if the series is too short.

References

Peng, C.-K., et al. (1994). "Mosaic organization of DNA nucleotides." Physical Review E, 49(2), 1685–1689. doi:10.1103/PhysRevE.49.1685

See also

ecgHRVnonlinear for the combined nonlinear analysis wrapper, ecgSampleEntropy for sample entropy, ecgHRVpoincare for Poincare plot descriptors.