Early Feasibility Study - Edwards APTURE Transcatheter Shunt System

Refined HFrEF Subgroup Inclusion Criteria: * A primary diagnosis of HFrEF (LVEF ≤ 40%), and * NYHA Class II, III, or IVa heart failure symptoms and * Documentation of at least one of the following in the past 12 months, such as: * Hospitalization for heart failure; or * Increased treatment for heart failure, including intravenous (IV) or higher-dose diuretic therapy. * Elevated heart failure biomarker levels (BNP or NT-proBNP) within the past 6 months. Note: Participants with NYHA Class II symptoms must have both a recent heart failure worsening event and elevated biomarker levels. Participants with NYHA Class III or IVa symptoms must have either a recent heart failure worsening event or elevated biomarker levels. * Stable Optimized GDMT - Maintained 6 months post-implant (includes stable GLP-1 RA) Refined HFrEF Subgroup Exclusion Criteria: * Severe HF defined as one or more of the following: * Ambulatory NT-proBNP value \>5,000 pg/ml or BNP value \>1,600 pg/ml * Left ventricular end-diastolic diameter (LVEDD) \>8 cm * Left ventricular ejection fraction (LVEF) \< 20% * ACC/AHA Stage D HF or non-ambulatory NYHA Class IV HF * Inotropic infusion (continuous or intermittent) within the past 6 months * Active listing on the cardiac transplant waiting list * More than mild right ventricular dysfunction * Valve disease * Mitral regurgitation \> moderate * Mitral stenosis \> mild * Tricuspid regurgitation \> moderate * Aortic regurgitation \> moderate * Aortic stenosis \> moderate * Body mass index (BMI) ≥45 * Myocardial infarction and/or any therapeutic invasive, non-valvular cardiac procedure within the past 3 months, or current indication for coronary revascularization * Stroke, transient ischemic attack, deep vein thrombosis, or pulmonary embolus within the past 6 months * Cardiac resynchronization therapy implanted within the past 12 months * Renal insufficiency as determined by serum creatinine (sCr) level \>2.5 mg/dL or estimated glomerular filtration rate (eGFR) \<25 ml/min/1.73 m2 * Performance of the 6-minute walk test with a distance \<100 m or \>450 m * Active endocarditis or infection requiring intravenous antibiotics within 3 months of scheduled index procedure * Presence of one or more of the following resting hemodynamic findings: 1. Mean pulmonary capillary wedge pressure (PCWP) \>35 mmHg 2. Mean right atrial pressure (RAP) \>15 mmHg 3. Mean PCWP-mean RAP gradient \< 5 mmHg 4. Pulmonary vascular resistance (PVR) ≥5 Wood Units (WU) 5. Cardiac index \<1.8 L/min/m2