Inclusion Criteria:

• Diagnosis and treatment for heart failure (HF) (regardless of left ventricular ejection fraction (LVEF)) for > 90 days prior to the date of consent:
  • Subjects should be on stable, optimally titrated medical therapy for at least 30 days, as recommended according to current American Heart Association (AHA)/American College of Cardiology (ACC) guidelines as standard-of-care for HF therapy in the United States, with any intolerance documented.
• GUIDE-HF Randomized Arm Only: NYHA Class II, III or IV HF symptoms documented within 30 days prior to consent.
• GUIDE-HF Single Arm Only: NYHA Class III HF symptoms documented within 30 days prior to consent.
• HF hospitalization (HFH) within 12 months prior to consent and/or elevated N-terminal pro-Brain Natriuretic Peptide (NT-proBNP) (or Brain Natriuretic Peptide (BNP)) within 30 days prior to consent defined as:
  • Subjects with LVEF ≤ 40%: NT-proBNP ≥ 1000 pg/mL (or BNP ≥ 250 pg/mL);
  • Subjects with LVEF > 40%: NT-proBNP ≥ 700 pg/mL (or BNP ≥ 175 pg/mL);
  • Thresholds for NT-proBNP and BNP (for both LVEF ≤ 40% and LVEF > 40%) will be corrected for body mass index (BMI) using a 4% reduction per BMI unit over 25 kg/m2 5. ≥ 18 years of age.
• Chest circumference of < 65 inches, if BMI is > 35 kg/m2.
• Written informed consent obtained from subject .
• Willing and able to upload pulmonary artery (PA) pressure information and comply with the follow-up requirements.

Exclusion Criteria:

• Intolerance to all neuro-hormonal antagonists (i.e., intolerance to angiotensin converting enzyme-inhibitors (ACE-I), angiotensin receptor blockers (ARB), angiotensin-neprilysin inhibitors (ARNi), hydralazine/isosorbide dinitrate and beta-blockers).
• ACC/AHA Stage D refractory HF (including having received or currently receiving pharmacologic circulatory support with inotropes).
• Received or are likely to receive an advanced therapy (e.g., mechanical circulatory support or cardiac transplant) in the next 12 months.
• NYHA Class IV HF patients with:
  • Continuous or chronic use of scheduled intermittent inotropic therapy for HF and an INTERMACS level of ≤ 4; OR
  • Persistence of fluid overload with maximum (or dose equivalent) diuretic intervention 
• Glomerular Filtration Rate (eGFR) < 25 mL/min and non-responsive to diuretic therapy, or receiving chronic dialysis.
• Inability to tolerate or receive dual antiplatelet therapy or anticoagulation therapy for one month post-implantation.
• Significant congenital heart disease that has not been repaired and would prevent implantation of the CardioMEMS™ PA Sensor.
• Implanted with mechanical right heart valve(s).
• Unrepaired severe valvular disease.
• Pregnant or planning to become pregnant in the next 12 months.
• An active, ongoing infection, defined as being febrile, an elevated white blood cell count, on intravenous antibiotics, and/or positive cultures (blood, sputum or urine).
• History of current or recurrent (≥ 2 episodes within 5 years prior to consent) pulmonary emboli and/or deep vein thrombosis.
• Major cardiovascular event (e.g., unstable angina, myocardial infarction, percutaneous coronary intervention, open heart surgery, or stroke, etc.) within 90 days prior to consent .
• Implanted with Cardiac Resynchronization Therapy (CRT)-Pacemaker (CRT-P) or CRT-Defibrillator (CRT-D) for less than 90 days prior to consent.
• Enrollment into another trial with an active treatment arm.
• Anticipated life expectancy of < 12 months.
• Any condition that, in the opinion of the Investigator, would not allow for utilization of the CardioMEMS™ HF System to manage the subject using information gained from hemodynamic measurements to adjust medications, including the presence of unexpectedly severe pulmonary hypertension (e.g., trans-pulmonary gradient >15) at implant right heart catheterization (RHC), a history of non-compliance, or any condition that would preclude CardioMEMS™ PA Sensor implantation.