Background: The use of implantable cardioverter defibrillators (ICDs) has been proven effective in the prevention of sudden cardiac death (SCD) and constitutes standard of care in appropriate populations. Combining a pressure sensing system with ICD therapy represents the first attempt to provide continuous hemodynamic monitoring using a device previously designed exclusively for SCD protection. Methods: REDUCEhf is a prospective, multicenter, randomized, single-blind, parallel-controlled trial designed to assess the safety of the Chronicle ICD system (single chamber ICD with a hemodynamic monitoring system) and the effectiveness of a management strategy guided by intracardiac pressure information among ICD-indicated New York Heart Association (NYHA) Class II or III heart failure (HF) patients. Those successfully implanted with a Chronicle ICD will be randomized to the Chronicle group or Control group. All patients will receive optimal medical therapy, but the hemodynamic information from the device will be used to guide patient management only in the Chronicle group. Primary endpoints include freedom from system-related complications and relative risk reduction of one or more HF-related events (hospitalizations, and emergency department and urgent care visits requiring intravenous therapy for HF). Approximately 850 patients will be enrolled in at least 75 centers in the United States to accrue the 419 events needed to test the primary effectiveness endpoint. Enrollment began in April 2006, and is expected to end during 2009. Conclusion: REDUCEhf will assess the safety of the Chronicle ICD system and the effectiveness of a patient management strategy based on remote access to continuous intracardiac pressures in reducing HF-related events. © 2007 Wiley Periodicals, Inc.