load_claris.m

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% BRAVEHEART - Open source software for electrocardiographic and vectorcardiographic analysis
% load_claris.m -- Load Abbott WorkMate Claris ASCII format ECGs
% Copyright 2016-2025 Hans F. Stabenau and Jonathan W. Waks
% 
% Source code/executables: /~https://github.com/BIVectors/BRAVEHEART
% Contact: braveheart.ecg@gmail.com
% 
% BRAVEHEART is free software: you can redistribute it and/or modify it under the terms of the GNU 
% General Public License as published by the Free Software Foundation, either version 3 of the License, 
% or (at your option) any later version.
%
% BRAVEHEART is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
% without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
% See the GNU General Public License for more details.
% 
% You should have received a copy of the GNU General Public License along with this program. 
% If not, see <https://www.gnu.org/licenses/>.
%
% This software is for research purposes only and is not intended to diagnose or treat any disease.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function [hz, I, II, III, avR, avF, avL, V1, V2, V3, V4, V5, V6] = load_claris(filename)

% Parse filename to get structure needed to find all of the corresponding
% text files since the data is stored in 1 lead per file

% It does not matter which lead is chosen - this function will parse all
% leads with a smilar structure:

% e.g. II.Session 18 - Page 1.2.TXT
% Will load all 12 <L>.Session 18 - Page 1.<N>.TXT where <L> is the lead and
% <N> is the order in which the signals appear in the Claris page which has
% no bearing on loading the signals.

% This load module will ONLY work if the file names are in the above format.

[d,f,~] = fileparts(filename);

common_file = strsplit(f,'.');
common_file = common_file{2};

% common_file now contains the structure of the data:
%<L>.common_file.<N>.txt

L =struct();
leads = fieldnames(ECG12);

for i = 3:14        % ECG12 fieldnames
    for N = 1:40    % Max number of leads from Claris page (may need to change)

        F = strcat(leads{i},'.',common_file,'.',num2str(N),'.txt');

        if isfile(fullfile(d,F))
            L.(leads{i}) = parse_claris_txt(fullfile(d,F));
            break;
        end

    end
end

% Need to have at least 8 leads
assert(numel(fieldnames(L)) >= 8, "Not enough files to make a 12-lead ECG");


% See if an information file exists
info_file_name = strsplit(common_file,' - ');
info_file_name = info_file_name{1};
info_file_name = strcat(info_file_name,' Information.TXT');

if isfile(fullfile(d,info_file_name))
    
    info_file = textread(fullfile(d,info_file_name),'%s','delimiter','\n');
    
    freq_idx = find(contains(info_file,'Sample Rate='));
    freq_cell = strsplit(info_file{freq_idx},'=');
    hz = str2double(extract(string(freq_cell{2}), digitsPattern));

    gain_idx = find(contains(info_file,'Channel Resolution='));
    gain_cell = strsplit(info_file{gain_idx},'=');
    gain_val = str2double(extract(string(gain_cell{2}), digitsPattern));

    gain_units = strsplit(gain_cell{2},' ');
    gain_units = gain_units{2};

    switch gain_units
        case 'nV/LSB'
            gain = gain_val / 1000000;
        otherwise
            error('gain units not in nV')
    end

else
    gain = 78/1000000;
    hz = 2000;
end


% Form row vectors gained properly
I = L.I' * gain;
II = L.II' * gain;

if isfield(L,'III')
    III = L.III' * gain;
else
    III = -I + II;
end

if isfield(L,'avR')
    avR = L.avR' * gain;
else
    avR = -0.5*I - 0.5*II;
end

if isfield(L,'avF')
    avF = L.avF' * gain;
else
    avF = II - 0.5*I;
end

if isfield(L,'avL')
    avL = L.avL' * gain;
else
    avL = I - 0.5*II;
end

V1 = L.V1' * gain;
V2 = L.V2' * gain;
V3 = L.V3' * gain;
V4 = L.V4' * gain;
V5 = L.V5' * gain;
V6 = L.V6' * gain;