Background: Implantable hemodynamic monitoring to guide heart failure (HF) therapy is a promising area of active research. The goal of this investigation was to evaluate the safety and technical performance of a novel wireless pulmonary artery pressure monitoring system in 17 patients with symptomatic HF. Methods: The monitoring system consists of a sensor, delivery catheter, interrogator, and home monitoring device. The HF sensor was implanted into a distal branch of the pulmonary artery. Pulmonary artery pressures were monitored using the external device, which powers the HF sensor and transmits the hemodynamic data from the patient's home to a secure Internet database. The accuracy of the system was assessed by comparison with standard right heart catheterization (RHC). Results: The HF sensor was safely and successfully implanted in all patients. Agreement between the HF sensor and RHC for systolic, diastolic, and mean pulmonary artery pressures was excellent, with correlation coefficients of 0.94, 0.85, and 0.95, respectively (all P < .0001). Using Bland-Altman plots, the average differences for systolic, diastolic, and mean pulmonary artery pressures for the HF sensor vs RHC were -4.4 ± 0.3, 2.5 ± 1.0, and -0.8 ± 1.3 mm Hg, respectively. There were no serious device-related adverse events. A postmortem analysis of the HF sensor in a patient who died 12 months after implant demonstrated complete endothelialization and no evidence of thrombosis. Conclusions: This trial supports the safety and accuracy of this pulmonary artery pressure monitoring system in patients with HF and the conduct of randomized trials of implantable hemodynamic monitoring in HF, using this system. © 2011 Mosby, Inc. All rights reserved.