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/*
***************************************************************************
*
* Author: Teunis van Beelen
*
* Copyright (C) 2018 - 2021 Teunis van Beelen
*
* Email: teuniz@protonmail.com
*
***************************************************************************
*
* This program 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, version 3 of the License.
*
* This program 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 <http://www.gnu.org/licenses/>.
*
***************************************************************************
*/
#include "ecg_statistics.h"
int ecg_get_hr_statistics(double *beat_interval_list, int beat_cnt, struct ecg_hr_statistics_struct *ecg_stats)
{
int i,
NN20=0,
NN50=0;
double d_tmp,
average_bpm=0,
average_rr=0,
sdnn_bpm=0,
sdnn_rr=0,
rmssd_rr=0,
*buf_bpm=NULL;
if(beat_interval_list == NULL) return -1;
if(ecg_stats == NULL) return -2;
if(beat_cnt < 3) return -3;
buf_bpm = (double *)malloc(sizeof(double) * beat_cnt);
if(buf_bpm == NULL)
{
return -4;
}
for(i=0; i<beat_cnt; i++)
{
if(beat_interval_list[i] < 1e-15)
{
free(buf_bpm);
buf_bpm = NULL;
return -5;
}
buf_bpm[i] = 60.0 / beat_interval_list[i];
average_bpm += buf_bpm[i];
average_rr += beat_interval_list[i];
if(i < (beat_cnt - 1))
{
d_tmp = (beat_interval_list[i] - beat_interval_list[i + 1]) * 1000.0;
rmssd_rr += (d_tmp * d_tmp);
if(((beat_interval_list[i] - beat_interval_list[i + 1]) > 0.02 ) || ((beat_interval_list[i + 1] - beat_interval_list[i]) > 0.02 ))
{
NN20++;
}
if(((beat_interval_list[i] - beat_interval_list[i + 1]) > 0.05 ) || ((beat_interval_list[i + 1] - beat_interval_list[i]) > 0.05 ))
{
NN50++;
}
}
}
average_bpm /= beat_cnt;
average_rr /= beat_cnt;
rmssd_rr /= beat_cnt;
rmssd_rr = sqrt(rmssd_rr);
for(i=0; i<beat_cnt; i++)
{
sdnn_bpm += (buf_bpm[i] - average_bpm) * (buf_bpm[i] - average_bpm);
sdnn_rr += (beat_interval_list[i] - average_rr) * (beat_interval_list[i] - average_rr);
}
sdnn_bpm = sqrt(sdnn_bpm / beat_cnt);
sdnn_rr = sqrt(sdnn_rr / beat_cnt);
ecg_stats->beat_cnt = beat_cnt;
ecg_stats->mean_rr = average_rr * 1000.0;
ecg_stats->sdnn_rr = sdnn_rr * 1000.0;
ecg_stats->rmssd_rr = rmssd_rr;
ecg_stats->mean_hr = average_bpm;
ecg_stats->sdnn_hr = sdnn_bpm;
ecg_stats->NN20 = NN20;
ecg_stats->NN50 = NN50;
ecg_stats->pNN20 = (NN20 * 100.0) / (beat_cnt - 1);
ecg_stats->pNN50 = (NN50 * 100.0) / (beat_cnt - 1);
free(buf_bpm);
buf_bpm = NULL;
return 0;
}
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