Heart Rate Variability Feature Set

Quantitative features of the heart rate variability for newborn infants

Features of Heart Rate Variability for Neonates (Matlab code)

Quantitative features of the heart rate variability (HRV) for newborn infants, see for example Garvey et al., 2021.

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Requirements | Functions | Example | References | Contact

Requires

Matlab (Mathworks) version R2020a or newer with the statistics toolbox. (Should work on older versions but not tested.)

Add this directory to the Matlab path. See how to add path for more details.

Main Functions

• Set parameters in hrv_EAR.m
• Estimate features with hrv_features.m

For more information on function type help <filename.m>.

Features

feature	descriptions
mean_NN	mean NN (normalised RR interval)
SD_NN	standard deviation of NN
VLF_power	power in the very low frequency band (0.01 to 0.04 Hz)
LF_power	power in the low frequency band (0.04 to 0.2 Hz)
HF_power	power in the high frequency band (0.2 to 2 Hz)
LF_HF_ratio	LF_power:HF_power ratio
TINN	triangular interpolation of NN interval histogram

TINN function from HRVTool.

Example

Extract the R-peaks from the ECG and store in a structured array. Here, we generate some fake R-peaks structure using random variables for 2 babies:

rr_test_st = fake_hrv_data();

Next, generate the feature set:

[hrv_feats_tb, hrv_feats_epochs_tb] = hrv_features(rr_test_st);

Two outputs in the form of tables:

1. hrv_feats_tb are the features averaged (median) over the entire HRV record:

head(hrv_feats_tb)

    code      mean_NN    SD_NN     VLF_power    LF_power    HF_power    LF_HF_ratio     TINN 
  ________    _______    ______    _________    ________    ________    ___________    ______

  {'ID_1'}    530.52     8.4727     191.72       16.312      1.5763       11.632       46.875
  {'ID_2'}    528.77     7.6981     223.51       12.846      1.4657       9.1349       39.062

2. hrv_feats_epochs_tb is the feature set for each epoch:

head(hrv_feats_epochs_tb)

    mean_NN    SD_NN     VLF_power    LF_power    HF_power    LF_HF_ratio     TINN     baby_ID    start_time_secs
    _______    ______    _________    ________    ________    ___________    ______    _______    _______________

    525.77     8.9454     372.22       23.771      1.6663       14.266       46.875    "ID_1"              0
    534.33     5.8692     96.396       7.7355      1.3898        5.566        31.25    "ID_1"         150.14
    531.85     6.0415      70.58       11.495      1.4131       8.1346       39.062    "ID_1"         300.25
    525.44     6.8949     184.19       16.832      1.3617       12.361       39.062    "ID_1"         449.89
    523.06     6.6994     99.013       13.728      1.4444       9.5049        31.25    "ID_1"          600.2
    520.05     6.0771      137.1       15.028      1.5397       9.7605        31.25    "ID_1"          749.9
    513.21     8.1552     152.14       10.954      1.5769       6.9467       46.875    "ID_1"         899.91
    509.46     6.3929     199.26       10.233      1.5758       6.4939       39.062    "ID_1"         1049.9

Epochs are 5 minutes with 50% overalp (set in hrv_EAR.m).

References

1. Garvey AA, Pavel AM, O’Toole JM, Walsh BH, Korotchikova I, Livingstone V, Dempsey EM, Murray DM, and Boylan GB. "Multichannel EEG abnormalities during the first 6 hours in infants with mild hypoxic–ischaemic encephalopathy." Pediatr Res. 2021; 90:117–24. DOI: 10.1038/s41390-021-01412-x

2. Goulding RM, Stevenson NJ, Murray DM, Livingstone V, Filan PM, Boylan GB. Heart rate variability in hypoxic ischaemic encephalopathy: correlation with EEG grade and two-year neurodevelopmental outcome. Pediatr Res. 2015 May;77(5):681-7. DOI: 10.1038/pr.2015.28

Contact

John M. O'Toole

Neonatal Brain Research Group,
INFANT Research Centre,
Department of Paediatrics and Child Health,
Room 2.19 UCC Academic Paediatric Unit, Cork University Hospital,
University College Cork,
Ireland

• email: jotoole AT ucc _dot ie