.TH PNNLIST 1 "21 February 2003" "WFDB 10.3.2" "WFDB Applications Guide"
.SH NAME
pnnlist, pNNx \- derive pNNx statistics from an annotation interval list or an annotation file
.SH SYNOPSIS
\fBpnnlist\fR [ \fIoptions\fR ... ]
\fBpNNx -r\fR \fIrecord\fR \fB-a\fR \fIinput-annotator\fR [ \fIoptions\fR ... ]
.SH DESCRIPTION
.PP
These programs derive \fIpNNx\fR, time domain measures of heart rate
variability defined for any time interval \fIx\fR  as the fraction of
consecutive normal sinus (NN) intervals that differ by more than \fIx\fR.
Conventionally, such measures have been applied to assess parasympathetic
activity using \fIx\fR = 50 milliseconds (yielding the widely-cited \fIpNN50\fR
statistic).
.SS pnnlist
.PP
This program takes as standard input an annotation interval list, containing
intervals in seconds and the (beat and non-beat) annotations that terminate
each interval; and outputs on standard output each unique NN increment (x) in
milliseconds, and the percentage of NN interval increments (pNNx) greater
than x.
.PP
Options for \fBpnnlist\fR may include:
.TP
\fB-h\fR
Print this usage summary.
.TP
\fB-i\fR \fIinc\fR
Compute and output pNNx for x = 0, \fIinc\fR, \fI2*inc\fR, ... milliseconds.
.TP
\fB-p\fR
Compute and output increments as percentage of initial intervals.
.TP
\fB-s\fR
Compute and output separate distributions of positive and negative intervals.
.SS pNNx
.PP
This shell script invokes \fBann2rr\fR(1) and \fBpnnlist\fR to obtain pNNx
statistics using a beat annotation file as input.  The input file must be
specified using the \fB-r\fR \fIrecord\fR and \fB-a\fR \fIannotator\fR
arguments.
.PP
Options for \fBpNNx\fR may include any of those usable with \fBpnnlist\fR,
as well as:
.TP
\fB-f\fR \fItime\fR
Begin at the specified \fItime\fR.  By default, \fBpNNx\fR starts at the
beginning of the record.
.TP
\fB-t\fR \fItime\fR
Stop at the specified \fItime\fR.
.SH EXAMPLES
.PP
These commands are functionally identical:
.br
    ann2rr -r nsrdb/16265 -a atr -A -i s8 -w | pnnlist
.br
    pNNx -r nsrdb/16265 -a atr
.PP
Each of these commands reads the \fBatr\fR (reference) annotations for
MIT-BIH Normal Sinus Rhythm Database (\fBnsrdb\fR) record 16265 (downloading
them directly from PhysioNet if the annotation file has not previously been
downloaded into a local (\fBnsrdb\fR).  These commands will then print each
unique NN interval increment in milliseconds along with the percentage of
intervals greater than that value.  Both of the examples above produce the
same output; the first few lines are shown below:
.br
      0       89.2738
.br
      7.8125  69.4564
.br
      15.625  53.3662
.br
      23.4375 40.8539
.br
      31.25   31.4265
.br
      39.0625 24.1817
.br
      46.875  18.4763
.br
      54.6875 14.1261
.br
      62.5    10.7312
.br
      70.3125 8.06025
.br
      78.125  6.09401
.br
      85.9375 4.56975
.br
      93.75   3.47841
.br
      101.562 2.66896
.br
              .
.br
              .
.br
              .

.SH ENVIRONMENT
.PP
It may be necessary to set and export the shell variable \fBWFDB\fR (see
\fBsetwfdb\fR(1)).
.SH SEE ALSO
\fBann2rr\fR(1), \fBsetwfdb\fR(1)
.SH AUTHOR
Joe E. Mietus (joe at physionet dot org)
.SH SOURCE
http://www.physionet.org/physiotools/pNNx/pNNx.src/pnnlist.c
.br
http://www.physionet.org/physiotools/pNNx/pNNx.src/pNNx