Objectives: The goal of this work was to evaluate the accuracy of a new heart failure (HF) sensor (HFS) (Heart Failure Sensor, CardioMEMS Inc., Atlanta, Georgia) pulmonary artery pressure (PAP) monitoring compared with Swan-Ganz (SG) (Hospira, Inc., Lake Forest, Illinois) catheterization and echocardiography (ECHO) in ambulatory HF patients. Background: There is an increasing interest in the development of ambulatory monitoring devices aiming to adjust therapy and prevent hospitalizations in HF patients. Methods: Twelve patients with HF and New York Heart Association functional class II to IV were included in this study. The HFS was deployed into the pulmonary artery under angiography, allowing wireless PAP measurement. Two independent blind operators performed 3 HFS measurements at each visit, with simultaneous ECHO at 2, 14, 30, 60, and 90 days. Swan-Ganz catheterization was performed at 0 and 60 days. Linear regression was used as a measure of agreement. Variability between methods and interobserver variability were evaluated by Bland-Altman analysis. Results: Mean age was 63 ± 14.6 years. Systolic PAP was 64 ± 22 mm Hg and 58 ± 22 mm Hg for HFS and SG, respectively (p < 0.01). Both methods showed a significant correlation (r2 = 0.96 baseline, r2 = 0.90 follow-up, p < 0.01), with a mean difference of 6.2 ± 4.5 mm Hg. Diastolic PAP was 23 ± 14 mm Hg and 28 ± 16 mm Hg for HFS and SG, respectively (r2 = 0.88 baseline, r2 = 0.48 follow-up, p < 0.01), with a mean difference of -1.6 ± 6.8 mm Hg. Systolic PAP was 60 ± 20 mm Hg and 62 ± 12 mm Hg for HFS and ECHO, respectively (r2 = 0.75, p < 0.01), with a mean difference of -2.6 ± 11 mm Hg. There was no significant interobserver difference. Conclusions: The HFS provides an accurate method for PAP assessment in the intermediate follow-up of HF patients. © 2007 American College of Cardiology Foundation.