PhysioNet: An NIH Research Resource for Complex Signals Madalena Costa,* ,† George B. Moody, ‡ Isaac Henry,* and Ary L. Goldberger* Abstract: The Research Resource for Complex Physiologic Signals, supported by the National Institutes of Health (NIH), is intended to promote and facilitate investigations in the study of cardiovascular and other complex biomedical signals. The resource website (www.physionet.org) has 3 interdependent components: 1) PhysioBank is an archive of well-characterized digital recordings of physiologic signals and related data, including databases of electrocardiogram and heart rate time series from patients with heart failure, coronary disease, sleep apnea syndromes, and cardiac arrhythmias; 2) PhysioToolkit is a library of open-source software for physiologic signal processing and analysis; and 3) PhysioNet, for which the resource is named, is an on-line forum for dissemination and exchange of recorded biomedical signals and open-source software for analyzing them. PhysioNet, in cooperation with the annual Computers in Cardiology conference, hosts a series of challenges inviting participants to tackle clinically interesting problems that are either unsolved or not well solved. PhysioNet invites contribu- tions of databases and software from the biomedical community. Key words: algorithms, arrhythmias, database, electrocardiogram, heart failure, ischemia, PhysioNet, signal analysis, sleep apnea. PhysioNet (http://www.physionet.org) is a web- based resource created in 1999 under the auspices of the National Center for Research Resources (NCRR) of the National Institutes of Health (NIH) to initiate, promote, and catalyze basic-to-bedside re- search in the study of complex physiologic data (1–5). It provides physiologic data in open, Internet- accessible archives, open-source software for the anal- ysis of physiologic data, and an on-line forum to facilitate cooperative analysis of data and the evalua- tion of proposed new algorithms. The need for this unique NCRR Biotechnology Center was motivated by the importance of complex signals in basic and clinical investigations and by the fact that vitally important, hypothesis-driven research on complex physiologic signals, both basic and clinical, had been hindered by the critical lack of data, analytic and human/communications resources. Structure of the Resource PhysioNet integrates core and collaborative research, service, dissemination, and training functions related From the *Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; † Faculty of Sciences, University of Lisbon, Lisbon; and ‡ Harvard-MIT Division of Health Sciences and Technology, Boston, MA. This work was supported by the National Institutes of Health/ National Center for Research Resources (P41-RR13622). Reprint requests: Ary L. Goldberger, MD, Cardiovascular Di- vision, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Boston, MA 02215; e-mail: agoldber@bidmc.harvard.edu. © 2003 Elsevier Inc. All rights reserved. 0022-0736/03/360S-0037$30.00/0 doi:10.1016/j.jelectrocard.2003.09.038 Journal of Electrocardiology Vol. 36 Supplement 2003 139