Main Inclusion Criteria:

1. Both heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) patients
2. NYHA Class II, Class III, or ambulatory Class IV HF
3. Receiving guideline directed medical and device therapy (GDMT) for heart failure
4. For NYHA Class III and ambulatory Class IV, at least one prior hospitalization for heart failure within the last year or elevated BNP level of at least 300 pg/ml or NT-proBNP level of at least 1,500 pg/ml. BNP/NT-ProBNP levels corrected for BMI
5. For NYHA Class II, must have both hospitalization and elevated BNP levels as above specifications

Main Exclusion Criteria:

1. Systolic blood pressure <90 or >160 mmHg
2. Presence of Intracardiac thrombus
3. Pulmonary hypertension with PASP of ≥70 mm/Hg or PVR > 4 WU
4. Significant RV dysfunction - TAPSE <12mm or RVFAC ≤25%
5. Left Ventricular End-Diastolic Diameter (LVEDD) >8cm
6. Moderate to severe aortic or mitral stenosis
7. Stroke or TIA or DVT within the last 6 months
8. eGFR <25 ml/min/1.73 m^2
9. Anatomical anomaly on TEE or ICE that precludes implantation of Shunt across fossa ovalis (FO) of the interatrial septum
10. Inadequate vascular access for implantation of shunt, e.g. femoral venous access for transseptal catheterization and inferior vena cava (IVC) is not patent

* Hemodynamic heart rhythm, or respiratory instability at time of Final Exclusion Criteria