Minimally Invasive Pericardiotomy as a New Treatment for Heart Failure

Inclusion Criteria * Age ≥ 30 years * Symptoms of severe dyspnea (III-IV) without evidence of a non-cardiac or ischemic explanation for dyspnea * EF of \> or = 50% determined on most recent imaging study within the preceding 5 years, with no change in clinical status suggesting potential for deterioration in systolic function * One of the following: * Previous hospitalization for HF with radiographic evidence (pulmonary venous hypertension, vascular congestion, interstitial edema, pleural effusion) of pulmonary congestion or * Catheterization documented elevated filling pressures at rest (PCWP ≥15 or LVEDP ≥18) or with exercise (PCWP ≥25) or * Elevated NT-proBNP (\>400 pg/ml) or BNP(\>200 pg/ml) or * Echo evidence of diastolic dysfunction/elevated filling pressures manifest by medial E/e' ratio≥15 and/or left atrial enlargement and chronic treatment with a diuretic for signs or symptoms of heart failure * Heart failure is primary factor limiting activity as indicated by answering # 2 to the following question: My ability to be active is most limited by: * Joint, foot, leg, hip or back pain * Shortness of breath and/or fatigue and/or chest pain * Unsteadiness or dizziness * Lifestyle, weather, or I just don't like to be active * Ambulatory (not wheelchair / scooter dependent) Exclusion Criteria * Recent (\< 1 month) hospitalization for heart failure * Left or right ventricular dilatation noted on cardiac imaging study prior to enrollment (either echocardiography or MRI). * Any hemoglobin (Hgb) \< 8.0 g/dl within 30 days prior to randomization * Any GFR \< 20 ml/min/1.73 m2 within 30 days prior to randomization * Significant alternative cause of dyspnea such as severe chronic obstructive pulmonary disease that is a primary contributor to symptoms in the opinion of the investigator * Ischemia thought to contribute to dyspnea in the opinion of the investigator * Acute coronary syndrome within 3 months defined by electrocardiographic (ECG) changes and biomarkers of myocardial necrosis (e.g., troponin) in an appropriate clinical setting (chest discomfort or anginal equivalent) * PCI, coronary artery bypass grafting, or new biventricular pacing within past 3 months * Obstructive hypertrophic cardiomyopathy * Known infiltrative cardiomyopathy (amyloid) * Pericardial disease (constriction, pericarditis, tamponade) * Active myocarditis * Complex congenital heart disease * Active collagen vascular disease * Significant valvular heart disease (greater than mild stenosis or greater than moderate regurgitant lesions) * Acute or chronic severe liver disease as evidenced by any of the following: encephalopathy, variceal bleeding, INR \> 1.7 in the absence of anticoagulation treatment * Terminal illness (other than HF) with expected survival of less than 1 year * Enrollment or planned enrollment in another therapeutic clinical trial in next 3 months. * Inability to comply with planned study procedures * Pregnancy or breastfeeding mothers