HeartRateVariability Analysis according to [1] X = heartratevariability(RRI [,units]) X = heartratevariability(qrsindex [,Fs]) X = heartratevariability(HDR) X = heartratevariability(HDR.EVENT) X = heartratevariability(filename) INPUT RRI R-R-intervales [in seconds] HDR as defined in the header structure of BioSig and returned by QRS-detection filename with event information Fs sampling rate - used for conversion into time axis units time units e.g. 'ms' (default: 's') OUTPUT X struct containing the results as defined by [1] X.meanRR meanRR = meanNN X.SDRR standard deviaation of RR intervales X.RMSSD rmsSD = SDSD NN50count1 NN50count2 NN50count pNN50 SD1 width of Poincar�plot; equivalent to sqrt(2)*RMSSD [2] SD2 length of Poincar�plot; i.e. 2SDRR�+SDSD�/2 [2] r_RR correlation coefficient [2] X.VLF power of very low frequency band (< 0.04 Hz) X.LF power of low frequency band (0.04-0.15 Hz) X.HF power of high low frequency band (0.15-0.4 Hz) X.TotalPower power of high low frequency band (0.15-0.4 Hz) X.LFHFratio LF/HF-ratio X.LFnu normalized units of LF power (0.04-0.15 Hz) X.HFnu normalized units of HF power (0.15-0.4 Hz) semilogy(X.f,X.ASpectrum) shows the spectral density function The spectral estimates are based on an autoregressive spectrum estimator of the data which is oversampled by a factor of 4 using the Berger method. The default model order is 15. In order to change these default settings, change in the source code line 211 (oversampling factor) and/or line 230 (order of the autoregressive model); see also: QRSDETECT, BERGER, EVENTCODES.TXT Reference(s): [1] Heart Rate Variability Standards of Measurement, physilogcial interpretation and clinical use. Taskforce of the European Society for Cardiology and the North Americal Society of Pacing and Electrophysiology. European Heart Journal (1996) 17, 354-381. [2] M. Brennan, M.Palaniswami, P. Kamen Do Existing Measures of Poincar�Plot Geometriy Reflect Nonlinear Features of Heart Rate Variablilty? IEEE Trans Biomedical Eng. 48(11),2001, [3] U. Rajendra Acharya, K. Paul Joseph,N. Kannathal, Choo Min Lim, Jasjit S. Suri. Heart rate variability: a review. Med Bio Eng Comput (2006) 44:1031�1051

- berger Resampling with the Berger algorithm

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