function [samples, time, rr_sec, rr_samp, HR, annotations, Fs, tstart, date] = read_qrs(record,datatype)
% [samples,time,rr_sec,rr_samp,HR,annotations,Fs] = read_qrs('1003.qrs')
% OVERVIEW: Reads the GE QRSDK format QRS detection
% file and converts to time-in-samples and annotations
% INPUT: record - QRSDK RR interval file name in string format
% datatype - type of data being read into function
% 'MARS' - default!
% THE FOLLOWING OPTIONS ARE NOT OPERATIONAL YET!
% 'CSV'
% 'WFDB'
% OUTPUT: samples - location of QRS annotations in samples from the
% beginning of the data
% time - location of QRS ann in time (seconds)
% rr_sec - rr interval values in seconds
% rr_samp - rr interval values in samples
% HR - beat-by-beat Heart Rate
% annotations - QRS annotation labels
% ? N = Normal
% ? B = Bundle Branch Block
% ? A = Aberrant
% ? V = Ventricular
% ? F = Ventricular Fusion
% ? S = Supraventricular
% ? E = Ventricular Esc.
% ? J = Junctional
% ? P = Ventricular Paced
% ? I = Idioventricular
% ? 00 = no signal
% ? 01 = noise on channel 1
% ? 02 = noise on channel 2
% ? 03 = noise on both channels (unreadable)
% Fs - sampling frequency
%
% ORIGINAL SOURCE AND AUTHORS:
% Qiao Li
%
% Dependent scripts written by various authors
% (see functions for details)
% COPYRIGHT (C) 2016
% LICENSE:
% This software is offered freely and without warranty under
% the GNU (v3 or later) public license. See license file for
% more information
%%
if nargin < 1
error('No input supplied')
end
if nargin < 2
datatype = 'MARS';
end
fid=fopen(record,'r');
% Adding the following for working on LINUX:
% move the pointer of file to offset 60 for reading starting time
% 8 characters + 2 NULL terminators
status=fseek(fid, 60, -1);
tstart=fread(fid,8,'*char'); % ECG Start Time HH:MM:SS
% move the pointer of file to offset 70 for reading starting date
status=fseek(fid, 70, -1);
date=fread(fid,9,'*char');%ECG Start Date DD-MMM-YY
% move the pointer of file to offset 90 for reading Fs
status=fseek(fid, 90, -1);
Fs=fread(fid,1,'short');
% timeincrement = 1/Fs;
% move the pointer of file to the offset 512 for annotations
status=fseek(fid,512,-1);
[ann_pair count]=fread(fid,2,'uint8');
ann_number=0;
time_accumulation=0;
while (count==2)
time=ann_pair(1);
ann=ann_pair(2);
while (ann_pair(2)==0 & ann_pair(1)==255) % if more than 255 samples between beats, read additional blocks
[ann_pair count]=fread(fid,2,'uint8');
time=time+ann_pair(1);
ann=ann_pair(2);
end
time_accumulation=time_accumulation+time;
ann_number=ann_number+1;
samples(ann_number)=time_accumulation;
annotations{ann_number,1}=char(ann);
rr_samp(ann_number)=time;
[ann_pair count]=fread(fid,2,'uint8');
end
rr_samp(1) = []; % delete first point
rr_samp(length(rr_samp)) = [];% delete last point
samples(1) = [];
samples(length(samples)) = [];% delete last point
annotations(1) = [];
annotations(length(annotations)) = [];% delete last point
HR = 60.0 ./ (rr_samp./Fs);
time = samples./Fs;
rr_sec = rr_samp./Fs;
% RRTachogram = [time',rr_sec,ann];
fclose(fid);
end