Compute_Hr function miscalculates.

[MishalJasmine]

I am working on the MIT-BIH records. The aim is to calculate the Heart Rate and find the maximum, minimum and the mean of the Heart rates. I extracted the ECG signal from the record, calculated the QRS peaks and calculated the Heart Rates using the compute_hr function from the wfdb package. Similarly extracted the QRS peaks from the annotation file and calculated the Heart Rates using the compute_hr function from the wfdb package. For the 101 record, the maximum Heart Rate from the annotations is 900.00bpm while the calculated qrs indices gave a maximum Heart rate of 111.3402bpm. I have this issue with many other records.

Python code:

record = wfdb.rdrecord(record_path, channels=[0])                                                                                                                                                                 
ann_ref = wfdb.rdann(record_path,'atr')
qrs_inds = processing.gqrs_detect(sig=record.p_signal[:,0], fs=record.fs)

heart_rate_wfdb = processing.compute_hr(sig_len=record.p_signal.shape[0], qrs_inds=qrs_inds, fs=record.fs)
heart_rate_wfdb = heart_rate_wfdb[np.logical_not(np.isnan(heart_rate_wfdb))]
heart_rate_min = "{0:.4f}".format(np.amin(heart_rate_wfdb))
heart_rate_max = "{0:.4f}".format(np.amax(heart_rate_wfdb))
heart_rate_mean = "{0:.4f}".format(np.mean(heart_rate_wfdb))

ref_heart_rate_wfdb = processing.compute_hr(sig_len=record.p_signal.shape[0], qrs_inds=ann_ref.sample[1:], fs=record.fs)
ref_heart_rate_wfdb = ref_heart_rate_wfdb[np.logical_not(np.isnan(ref_heart_rate_wfdb))]
ref_heart_rate_min = "{0:.4f}".format(np.amin(ref_heart_rate_wfdb))
ref_heart_rate_max = "{0:.4f}".format(np.amax(ref_heart_rate_wfdb))
ref_heart_rate_mean = "{0:.4f}".format(np.mean(ref_heart_rate_wfdb))`

Can someone tell me what is that I am doing wrong?

[m0bi5]

Facing the same issue, were you able to figure it out?

[MishalJasmine]

@m0bi5 I oberserved two things,

1. First we need to classify annotations as beat and non-beat annotations. The annotations classified as beat annotations, need to be passed to the compute_hr.
2. If you observe the compute_hr function, the result is an array whose length is equivalent to the length of the input ECG signal. When additional Heart Rate parameters are calculated, it may result in conflicts.

I hope this will help you.