Multicenter, Prospective, Randomized Controlled, Blinded Trial, with a Non-implant Control group; 1:1 randomization.

Following supine bicycle exercise testing to assess eligibility, the eligible patients are randomized to the treatment or control group.

All patients will be sedated, and both treatment and control arm patients will undergo placement of a femoral venous access sheath after randomization.

Patients randomized to the treatment arm will undergo a fluoroscopically and intra-cardiac echocardiography (ICE), or transesophageal echocardiography (TEE) guided trans-septal puncture and IASD System II implant procedure. Patients randomized to the control arm will undergo ICE from the femoral vein or TEE for examination of the atrial septum and left atrium.

Patients will be evaluated at pre-specified time intervals and followed for 5 years.

All patients will be unblinded after the 24 month follow up visit.

SELECT INCLUSION CRITERIA

• Chronic symptomatic Heart Failure (HF) documented by one or more of the following:

  • Symptoms of HF requiring current treatment with diuretics for ≥ 30 days AND
  • NYHA class II with a history of > NYHA class II; OR NYHA class III, or ambulatory NYHA class IV symptoms (paroxysmal nocturnal dyspnea, orthopnea, dyspnea on mild or moderate exertion) at screening; or signs (any rales post cough, chest x-ray demonstrating pulmonary congestion,) within past 12 months; AND
  • ≥ 1 HF hospital admission (with HF as the primary, or secondary diagnosis); or treatment with intravenous (IV), or intensification of oral diuresis for HF in a healthcare facility within the 12 months prior to study entry; OR an NT-pro BNP value > 150 pg./ml in normal sinus rhythm, > 450 pg./ml in atrial fibrillation, or a BNP value > 50 pg./ml in normal sinus rhythm, > 150 pg./ml in atrial fibrillation within the past 6 months.

• Ongoing stable GDMT HF management and management of potential comorbidities according to the 2013 ACCF/AHA Guidelines for the management of Heart Failure (with no significant changes [>100% increase or 50% decrease], excluding diuretic dose change for a minimum of 4 weeks prior to screening) that is expected to be maintained without change for 6 months

• Age ≥ 40 years old, LV ejection fraction (EF) ≥ 40% within the past 3 months, without previously documented EF <30% (within the past 3 years)

• Elevated PCWP with a gradient compared to right atrial pressure (RAP), documented by end-expiratory PCWP during supine ergometer exercise ≥ 25mmHg, and greater than RAP by ≥ 5 mmHg

SELECT EXCLUSION CRITERIA

• MI and/or percutaneous cardiac intervention within past 3 months; CABG in past 3 months, or current indication for coronary revascularization; AVR (surgical AVR or TAVR) within the past 12 months.

• Cardiac Resynchronization Therapy initiated within the past 6 months

• Advanced heart failure defined as one or more of the below:

  • ACC/AHA/ESC Stage D heart failure, non-ambulatory NYHA Class IV HF;
  • Cardiac index < 2.0 L/min/m2
  • Inotropic infusion (continuous or intermittent) for EF< 40% within the past 6 months
  • Patient is on the cardiac transplant waiting list

• Inability to perform 6 minute walk test (distance < 50 m), OR 6 minute walk test > 600m

• History of stroke, transient ischemic attack (TIA), deep vein thrombosis (DVT), or pulmonary emboli within the past 6 months

• Presence of significant valve disease defined by the site cardiologist as:

  • Mitral valve regurgitation defined as grade ≥ 3+ MR
  • Tricuspid valve regurgitation defined as grade ≥ 2+ TR
  • Aortic valve disease defined as ≥ 2+ AR or > moderate AS

• Known clinically significant untreated carotid artery stenosis likely to require intervention

• Currently requiring dialysis; or estimated-GFR <25ml/min/1.73 m2 by CKD-Epi equation