Objectives: The purpose of this study was to determine whether a heart failure (HF) management strategy using continuous intracardiac pressure monitoring could decrease HF morbidity. Background: Patients with HF may experience frequent decompensations that require hospitalization despite intensive treatment and follow-up. Methods: The COMPASS-HF (Chronicle Offers Management to Patients with Advanced Signs and Symptoms of Heart Failure) study was a prospective, multicenter, randomized, single-blind, parallel-controlled trial of 274 New York Heart Association functional class III or IV HF patients who received an implantable continuous hemodynamic monitor. Patients were randomized to a Chronicle (Medtronic Inc., Minneapolis, Minnesota) (n = 134) or control (n = 140) group. All patients received optimal medical therapy, but the hemodynamic information from the monitor was used to guide patient management only in the Chronicle group. Primary end points included freedom from system-related complications, freedom from pressure-sensor failure, and reduction in the rate of HF-related events (hospitalizations and emergency or urgent care visits requiring intravenous therapy). Results: The 2 safety end points were met with no pressure-sensor failures and system-related complications in only 8% of the 277 patients who underwent implantation (all but 4 complications were successfully resolved). The primary efficacy end point was not met because the Chronicle group had a nonsignificant 21% lower rate of all HF-related events compared with the control group (p = 0.33). A retrospective analysis of the time to first HF hospitalization showed a 36% reduction (p = 0.03) in the relative risk of a HF-related hospitalization in the Chronicle group. Conclusions: The implantable continuous hemodynamic monitor-guided care did not significantly reduce total HF-related events compared with optimal medical management. Additional trials will be necessary to establish the clinical benefit of implantable continuous hemodynamic monitor-guided care in patients with advanced HF. © 2008 American College of Cardiology Foundation.