COMPASS-HF was a prospective, two-arm, randomized (1:1), multi-center, parallel controlled study. The purpose of the randomized study was to test the safety of an implantable hemodynamic monitor (IHM) and pressure sensor lead. The premise of this study was to compare the effectiveness of a novel heart failure management strategy based on information obtained from the IHM system in reducing heart failure morbidity compared to a strategy based on standard medical care alone.

COMPASS-HF was a prospective, two-arm, randomized (1:1), multi-center, parallel controlled study. The purpose of the randomized study was to test the safety of an implantable hemodynamic monitor (IHM) and pressure sensor lead. The premise of this study was to compare the effectiveness of a novel heart failure management strategy based on information obtained from the IHM system in reducing heart failure morbidity compared to a strategy based on standard medical care alone.

After baseline evaluation and verification that entrance criteria were met, all subjects were implanted with a Chronicle IHM and pressure sensor lead. Following successful implantation, subjects were randomized to either the CHRONICLE group or CONTROL group. Subjects randomized to the CHRONICLE group were managed using Chronicle, specifically trended RV and estimated PA pressure, heart rate and activity data, whereas subjects randomized to the CONTROL group were treated conventionally without the use of the Chronicle data. In the case that implantation was not successful, subjects were exited from the study if no procedure related adverse events were identified; procedure related adverse events were followed through to resolution before the subject were withdrawn from the study.

Subjects remained randomized until their six month clinic visit had been completed. Following the subject's six month visit, clinicians were granted access to the CONTROL subject's trended Chronicle data on the Chronicle website, and subjects were seen in the clinic for a protocol-required visit every six months until exit from the study.

Inclusion Criteria:

• Subjects with heart failure classified as New York Heart Association (NYHA) Class III and IV
• Subject has been managed with standard medical therapy for heart failure (such as diuretic, angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blockers (ARB), and beta-blocker for at least 3 months prior to the baseline evaluation
• Subject must have at least one heart failure-related hospitalization or emergency department visit requiring intravenous treatment within 6 months prior to baseline evaluation

Exclusion Criteria:

• Subjects who are likely to be transplanted within 6 months from randomization or will remain hospitalized until transplantation
• Subjects with severe COPD or restrictive airway disease (recommended FEV1 less than or equal to 1 liter or 50% predicted)
• Subjects who are on continuous positive inotropic therapy
• Subjects with known atrial or ventricular septal defects
• Subjects with mechanical right heart valves
• Subjects with stenotic tricuspid or pulmonary valves
• Subjects with a presently implanted non-compatible pacemaker or ICD
• Subjects with cardiac resynchronization therapy which has not achieved optimal programming for more than 3 months
• Subjects with a major cardiovascular event within 3 months prior to baseline evaluation
• Subjects with a severe non-cardiac condition limiting 6 month survival
• Subjects with a primary diagnosis of pulmonary artery hypertension
• Subjects with serum creatinine greater than or equal to 3.5 mg/dL or on chronic renal dialysis
• Subjects enrolled in concurrent studies that may confound the results of this study
• Women who are pregnant or with child bearing potential and who are not on a reliable form of birth control