Implantable Cardioverter Defibrillator Electrogram Adjudication for Device Registries: Methodology and Observations from ALTITUDE BRIAN D. POWELL, M.D.,* YONG-MEI CHA, M.D.,* SAMUEL J. ASIRVATHAM, M.D.,* DAVID A. CESARIO, M.D.,† MICHAEL CAO, M.D.,† PAUL W. JONES, M.S.,‡ MILAN SETH, M.S.,‡ LESLIE A. SAXON, M.D.,† and F. ROOSEVELT GILLIAM III, M.D.§ From the *Mayo Clinic, Rochester, Minnesota; †University of Southern California, Los Angeles, California; ‡Boston Scientific, St. Paul, Minnesota; and §Cardiology Associates of NE Arkansas, Jonesboro, Arkansas Background: The increasing use of remote monitoring with the associated large retrievable databases provides a unique opportunity to analyze observations on implantable cardioverter-defibrillator (ICD) therapies. Adjudication of a large number of stored ICD electrograms (EGMs) presents a unique challenge. The ALTITUDE study group was designed to use the LATITUDE remote monitoring system to evaluate ICD patient outcomes across the United States. Methods and Results: Of 81,081 patients on remote monitoring, a random sample of 2,000 patients having 5,279 shock episodes was selected. The ALTITUDE EGM review committee was comprised of seven electrophysiologists from four institutions. An online EGM adjudication system was designed. Episodes were classified as appropriate (70% of shock episodes) or inappropriate ICD therapies (30%). Light’s Kappa was used to assess agreement. Interobserver and intraobserver Kappa scores for dual-chamber ICDs were 0.84 (0.71–0.91) and 0.89 (0.82–0.95), consistent with substantial agreement. Interobserver and intraobserver Kappa scores for single-chamber ICDs were 0.61 (0.54–0.67) and 0.69 (0.59–0.79). The rhythm categories of “nonsustained arrhythmia” and “polymorphic and monomorphic ventricular tachycardia” resulted in the greatest degree of discordant adjudication between reviewers. Conclusions: This method of adjudication of a large volume of stored EGM data prior to device therapies will allow new observations in regards to device performance and has the potential to improve device programming and design. There was substantial interreviewer agreement for rhythm classification. Agreement was greater for dual-chamber compared to single-chamber devices, indicating the atrial lead adds diagnostic value in rhythm interpretation. (PACE 2011; 34:1003–1012) defibrillators, implantable cardiac resynchronization therapy, database management systems monitoring, ambulatory arrhythmias, cardiac methods Background Implanted cardioverter defibrillators (ICDs) and cardiac resynchronization therapy defibril- lators (CRT-Ds) have been shown to reduce the risk of sudden cardiac death in heart failure Disclosures: B.D. Powell, Boston Scientific Corp., Biotronik; Y. Cha, Boston Scientific Corp., Medtronic, St. Jude Medical; S.J. Asirvatham, Boston Scientific Corp.; M. Cao, Boston Scientific Corp.; D.A. Cesario, Boston Scientific Corp., St. Jude Medical, Medtronic, Inc.; P.W. Jones, Boston Scientific Corp.; S. Milan, Boston Scientific Corp.; L.A. Saxon, Boston Scientific Corp.; F.R. Gilliam, Boston Scientific Corp. Financial Support for this study was provided by Boston Scientific, St. Paul, Minnesota. Address for reprints: Brian D. Powell, M.D., Mayo Clinic, 200 First St SW, Rochester, MN 55905. Fax: 507266-9142; e-mail: powell.brian@mayo.edu Received June 11, 2010; revised January 5, 2011; accepted January 27, 2011. doi: 10.1111/j.1540-8159.2011.03093.x patients. 1–3 Hundreds of thousands of individ- uals currently have an ICD or CRT-D device. Randomized clinical trials have demonstrated the effectiveness of device therapies for improved survival. However, little is known about outcomes of patients with ICDs implanted in community settings, and even less is known about how the device shock and tachycardia therapies are utilized over time in device recipients followed across the United States. Remote monitoring of ICD and CRT-D devices provide a means for device data to be transmitted from a patient’s home to his or her health care provider more frequently than the standard quarterly visits to device follow- up clinic. 4 Remote monitoring systems with a central data collection center provide a repository to allow evaluation of stored electrograms (EGMs) from spontaneous arrhythmia episodes in tens of thousands of device recipients over the longevity of the device. We recently reported ICD and CRT- D patient survival and the incidence of appro- priate and inappropriate shocks in patients being C 2011, The Authors. Journal compilation C 2011 Wiley Periodicals, Inc. PACE, Vol. 34 August 2011 1003