IHR(1)

NAME
ihr - calculate instantaneous heart rate

SYNOPSIS
ihr -r record -a annotator [ options ... ]

DESCRIPTION

ihr reads an annotation file (specified by the annotator and record arguments) and produces an instantaneous heart rate signal (from the reciprocals of the interbeat intervals.) Unlike tach(1), however, ihr does not resample its output in order to obtain uniform time intervals between output samples. (If there is any variation whatsoever in heart rate, the intervals between output samples will be non-uniform.) This property makes the output of ihr unsuitable for conventional power spectral density estimation, but ideal for PSD estimation using the Lomb periodogram (see lomb(1)).

Options include:

-d tolerance
    Reject beat-to-beat heart rate changes exceeding tolerance (in beats per minute; default: 10). Any intervals for which the calculated heart rate would differ by more than the specified tolerance are simply excluded from the output series. To disable this behavior, use a large value for tolerance (e.g., 10000).

-f time
    Begin at the specified time in record (default: the beginning of record).

-h  Print a usage summary.

-t time
    Process until the specified time in record (default: the end of the record).

-x  Exclude all intervals adjacent to abnormal beats. By default, such intervals are included (unless they are rejected by the tolerance criterion), and a third column is used to flag these intervals as abnormal (a zero in the third column means the interval is normal, a one means it is abnormal).

Reference (`atruth') annotation files can be used as input to ihr, but files that contain manually-inserted annotations are less suitable, since annotation placement is likely to be less consistent than in annotation files generated by programs such as sqrs(1).

The shell variable WFDB should be set and exported (see setwfdb(1)).

SEE ALSO
lomb(1), setwfdb(1), sqrs(1), tach(1)

AUTHOR
George B. Moody (george@mit.edu)

SOURCE
http://www.physionet.org/physiotools/wfdb/app/ihr.c