Struct FrequencyMetrics

pub struct FrequencyMetrics<T> {
    pub lf: T,
    pub hf: T,
    pub vlf: T,
}

A struct representing frequency-domain heart rate variability (HRV) metrics.

The FrequencyMetrics struct holds key frequency-domain parameters that are calculated from heart rate variability (HRV) data. These metrics are derived by analyzing the power spectral density (PSD) of the RR intervals, which can provide insights into the autonomic nervous system’s regulation of the heart and overall cardiovascular health.

These frequency-domain metrics provide a deeper understanding of heart rate variability by focusing on the different frequency bands that reflect various physiological processes and autonomic nervous system regulation.

Fields

lf: T

Low Frequency (LF) power. Reflects sympathetic and parasympathetic balance, typically between 0.04 and 0.15 Hz.

hf: T

High Frequency (HF) power. Primarily associated with parasympathetic nervous system activity, typically between 0.15 and 0.40 Hz.

vlf: T

Very Low Frequency (VLF) power. Represents the power of frequencies below 0.04 Hz, associated with long-term regulatory processes.

Implementations

impl<T: Float + Sum<T> + Copy + Debug + Signed + 'static + AddAssign + Send + Sync + FromPrimitive> FrequencyMetrics<T>

pub fn compute_sampled(sampled_rr_intervals: &[T], rate: T) -> Self

Computes frequency-domain metrics (LF, HF, VLF) from sampled RR intervals.

The compute_sampled function computes the frequency-domain metrics of heart rate variability (HRV) using the Welch method for spectral density estimation. It requires a list of sampled RR intervals and a specified sampling rate to estimate the power spectral density (PSD) and extract the frequency components in the low-frequency (LF), high-frequency (HF), and very low-frequency (VLF) bands.

This method employs Welch’s periodogram to calculate the spectral density, with specified frequency bands for LF, HF, and VLF, and computes the total power in these bands using trapezoidal integration.

Parameters

• sampled_rr_intervals: A slice of sampled RR intervals, representing the time differences between successive heartbeats, after being adjusted for the mean interval.
• rate: The sampling rate used to interpolate the RR intervals, expressed in Hz.

Returns

A FrequencyMetrics struct containing the computed LF, HF, and VLF values, which represent the power in their respective frequency bands.

Example

use cardio_rs::frequency_domain::FrequencyMetrics;
use cardio_rs::utils::test_data::RR_INTERVALS;

let rate = 4.0;
let frequency_metrics = FrequencyMetrics::compute_sampled(RR_INTERVALS, rate);

Notes

The frequency bands for LF, HF, and VLF are typically:

• LF: 0.04 - 0.15 Hz
• HF: 0.15 - 0.40 Hz
• VLF: 0.003 - 0.04 Hz

pub fn compute(rr_intervals: &[T], rate: T) -> Self

Computes frequency-domain metrics (LF, HF, VLF) from raw RR intervals by first interpolating them.

The compute function computes the frequency-domain metrics of heart rate variability (HRV) based on raw RR intervals by first interpolating them to a uniform 4 Hz rate. It utilizes the compute_sampled function to estimate the spectral density of the interpolated RR intervals, providing the LF, HF, and VLF values.

Parameters

• rr_intervals: A slice of raw RR intervals, representing the time differences between successive heartbeats.
• rate: The sampling rate used to interpolate the RR intervals, expressed in Hz.

Returns

A FrequencyMetrics struct containing the computed LF, HF, and VLF values, which represent the power in their respective frequency bands.

Example

use cardio_rs::frequency_domain::FrequencyMetrics;
use cardio_rs::utils::test_data::RR_INTERVALS;

let frequency_metrics = FrequencyMetrics::compute(RR_INTERVALS, 4.);

Notes

This method interpolates the RR intervals using a specified rate (defaulted to 4 Hz) before passing them to the compute_sampled method for spectral analysis.

Trait Implementations

impl<T: Clone> Clone for FrequencyMetrics<T>

fn clone(&self) -> FrequencyMetrics<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for FrequencyMetrics<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Default> Default for FrequencyMetrics<T>

fn default() -> FrequencyMetrics<T>

Returns the “default value” for a type.

impl<T: PartialEq> PartialEq for FrequencyMetrics<T>

fn eq(&self, other: &FrequencyMetrics<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: Copy> Copy for FrequencyMetrics<T>

impl<T> StructuralPartialEq for FrequencyMetrics<T>