This is a prospective, single arm feasibility study to establish safety and performance of the PAS-C System in subjects with heart failure and elevated left atrial pressure.

Key Inclusion Criteria:

• Documented chronic, symptomatic heart failure and NYHA Class II, Class III or ambulatory Class IV at the time of screening visit and receiving guideline directed medical therapy.
• At least one hospitalization or emergency department visit with heart failure as the primary or secondary diagnosis or intravenous diuretic treatment for heart failure or documentation of elevated BNP.
• LVEF ≥ 40%.
• Echocardiographic evidence of diastolic dysfunction during the baseline echocardiography:
• Per baseline exercise right heart catheterization, site measured elevated left atrial pressure with a gradient compared to right atrial pressure.

Key Exclusion Criteria:

• Stroke or thromboembolic event in the past 6 months.
• Severe or advanced heart failure such as Stage D heart failure, non-ambulatory NYHA Class IV, cardiac index less than 2.0 L/min/m2, LVEDD > 6 cm, or received inotropic therapy for LVEF less than 40% within 6 months prior to enrollment.
• Any of the following within 3 months prior to enrollment: myocardial infarction, percutaneous cardiac intervention, CABG, cardiac resynchronization therapy, AICD, or indicated for coronary revascularization at the time of enrollment.
• More than moderate valve disease (mitral, tricuspid, aortic) at the time of enrollment.
• Chronic pulmonary disease requiring continuous home oxygen or hospitalization within prior 12 months for pulmonary disease.
• BMI > 40.
• 6-minute Walk Test distance less than 100 m or greater than 450 m performed during baseline screening, or unable to perform baseline bicycle exercise test.
• Any of the following at the time of baseline screening: moderate or worse right heart dysfunction, requires dialysis, atrial fibrillation with ventricular rate > 100 bpm, systolic blood pressure greater than 170 mmHg (average of 3 measurements at baseline).
• Evidence of precapillary pulmonary hypertension defined as PVR > 2 Wood units at rest, TPG > 15 at rest or with exercise, resting RA > 15 mmHg, or RA to PCWP ratio > 0.7 at rest and with exercise.
• Anatomic anomaly that precludes creation of interatrial shunt.