function [simPAFdata, initialParameters] = simPAF_ECG_generator(rrLength, realRRon, realVAon, realAAon, AFburden, stayInAF, APBrate, noiseType, noiseRMS, onlyRR)
% [] = simPAF_ECG_generator() returns a 15-by-N matrix containing 15 lead
% ECGs. Three types of ECG signals can be generated: sinus rhythm (SR) (AF burden set to 0,
% AF (AF burden set to 1) or PAF (AF burden any value from the interval
% (0, 1)). Standard leads I, II, III, aVR, aVL, aVF, V1, V2, V3, V4, V5, V6
% and Frank leads X, Y, Z are generated (sampling frequency 1000 Hz).
%
% Copyright (C) 2017 Andrius Petrenas
% Biomedical Engineering Institute, Kaunas University of Technology
%
% Available under the GNU General Public License version 3
% - please see the accompanying file named "LICENSE"
%
% Generated leads:
% multileadVA(1,:) - I multileadVA(7,:) - V1 multileadVA(13,:) - X
% multileadVA(2,:) - II multileadVA(8,:) - V2 multileadVA(14,:) - Y
% multileadVA(3,:) - III multileadVA(9,:) - V3 multileadVA(15,:) - Z
% multileadVA(4,:) - aVR multileadVA(10,:) - V4
% multileadVA(5,:) - aVL multileadVA(11,:) - V5
% multileadVA(6,:) - aVF multileadVA(12,:) - V6
%
% Input arguments:
% rrLength indicates the length of the desired ECG signal (in RR intervals)
%
% realRRon 1 indicates that real RR intervals are used, 0 - synthetic
% realVAon 1 indicates that real ventricular activity is used, 0 - synthetic
% realAAon 1 indicates that real atrial activity is used, 0 - synthetic
%
% onlyRR 1 - only RR intervals are generated, 0 - multilead ECG is generated
%
% AFburden is a value between 0 and 1. 0 - the entire signal is SR,
% 1 - the entire signal is AF.
%
% stayInAF denotes the probability to stay in AF.
%
% APBrate is any value from 0 to 0.5, where 0 implies that no APBs occur,
% whereas 0.5 means that 50 % of all beats are APBs. Note that P wave
% morphology is altered only when synthetic atrial activiti is used
% (realAAon = 0).
%
% noiseType: a number from 0 to 4
% 0 - no noise added (noise RMS = 0 mV)
% 1 - motion artefacts
% 2 - electrode movement artefacts
% 3 - baseline wander
% 4 - mixture of type 1, type 2 and type 3 noises
%
% noiseLevel - noise level in milivolts, i.e. 0.02 corresponds to 20 uV
%
% Output arguments:
% simPAFdata returns generated data (multilead ECG, multilead ventricular
% activity, multilead atrial activity, QRS index, etc.). initialParameters
% returns initial parameter values used to generated ECG signals.
%
% Known problems:
% *AV node model used for generating RR intervals during AF is relatively slow.
% *Synthetic P wave amplitude is nearly 1.5 lower in several leads than that
% observed in reality (at least for healthy patients). Parameters for
% simulating Type 2 P waves are taken from the paper by Havmoller et al.
% Age-related changes in P wave morphology in healthy subjects.
% BMC Cardiovascular Disorders, 7(1), 22, 2007.
% *Interpolated TQ intervals (using a cubic spline interpolation) sometimes
% do not look realistic.
%
switch onlyRR
case 1 % only RR intervals are generated
% Generate initial parameters (fibrillatory frequency)
fibFreqz = simPAF_gen_initial_parameters;
% Generate RR intervals
[rr, targets_SR_AF, targets_APB, pafBoundaries, pafEpisLength] = simPAF_gen_rr_intervals(rrLength, fibFreqz, APBrate, realRRon, stayInAF, AFburden);
simPAFdata.rr = rr;
simPAFdata.multileadECG = [];
simPAFdata.multileadVA = [];
simPAFdata.multileadAA = [];
simPAFdata.multileadNoise = [];
simPAFdata.QRSindex = [];
simPAFdata.targets_SR_AF = targets_SR_AF;
simPAFdata.targets_APB = targets_APB;
simPAFdata.pafBoundaries = pafBoundaries;
simPAFdata.pafEpisLength = pafEpisLength;
simPAFdata.ecgLength = [];
initialParameters.fibFreqz = fibFreqz;
initialParameters.rrLength = rrLength;
initialParameters.APBrate = APBrate;
initialParameters.realRRon = realRRon;
initialParameters.realVAon = realVAon;
initialParameters.realVAon = realAAon;
initialParameters.stayInAF = stayInAF;
initialParameters.AFburden = AFburden;
initialParameters.noiseType = noiseType;
initialParameters.noiseRMS = noiseRMS;
case 0 % multilead ECG is generated
% Check for errors:
if (realVAon == 0) && (realAAon == 1)
msg = ('Selection of synthetic ventricular activity and real atrial activity is not allowed');
error('MyComponent:incorrectType', msg);
end
% Generate initial parameters (fibrillatory frequency)
fibFreqz = simPAF_gen_initial_parameters;
% Generate RR intervals
[rrIn, targets_SR_AF, targets_APB, pafBoundaries, pafEpisLength] = simPAF_gen_rr_intervals(rrLength, fibFreqz, APBrate, realRRon, stayInAF, AFburden);
% Generate multilead ventricular activity
[QRSindex, rr, multileadVA, ecgLength] = simPAF_gen_multilead_VA(rrLength, targets_SR_AF, rrIn, AFburden, realVAon, realAAon);
% Generate multilead atrial activity
multileadAA = simPAF_gen_multilead_AA(targets_SR_AF, targets_APB, QRSindex, fibFreqz, realAAon, ecgLength, AFburden);
% Generate multilead noise
multileadNoise = simPAF_gen_noise(ecgLength, noiseType, noiseRMS);
% Generate multilead noise
multileadECG = multileadVA + multileadAA + multileadNoise;
simPAFdata.rr = rr;
simPAFdata.multileadECG = multileadECG;
simPAFdata.multileadVA = multileadVA;
simPAFdata.multileadAA = multileadAA;
simPAFdata.multileadNoise = multileadNoise;
simPAFdata.QRSindex = QRSindex;
simPAFdata.targets_SR_AF = targets_SR_AF;
simPAFdata.targets_APB = targets_APB;
simPAFdata.pafBoundaries = pafBoundaries;
simPAFdata.pafEpisLength = pafEpisLength;
simPAFdata.ecgLength = ecgLength;
initialParameters.fibFreqz = fibFreqz;
initialParameters.rrLength = rrLength;
initialParameters.APBrate = APBrate;
initialParameters.realRRon = realRRon;
initialParameters.realVAon = realVAon;
initialParameters.realVAon = realAAon;
initialParameters.stayInAF = stayInAF;
initialParameters.AFburden = AFburden;
initialParameters.noiseType = noiseType;
initialParameters.noiseRMS = noiseRMS;
end
end