These data are from the file
in the 'RR interval time series modeling:
A challenge from PhysioNet and Computers in Cardiology 2002' site of PhysioNet.
sponsored by NIH's National Center for Research Resources.
The data are the RR intervals (beat-to-beat intervals measured between successive peaks of the QRS complex) for patients in normal sinus rhythm (record 16265 of the MIT-BIH database).