This is a phase 2 randomized, double-blind, placebo-controlled study to evaluate the cardiac and renal effects of short term treatment with elamipretide in patients hospitalized with congestion due to heart failure

Inclusion Criteria:

• A history of chronic heart failure for at least 1 month
• Treated with ≥40 mg/day of furosemide or bumetanide ≥1 mg/day or torasemide ≥10 mg/day for at least 1 month
• In-hospital observation/admission and treatment for ≤72 hours and primary cause for admission is heart failure with persistent congestion in the opinion of the Investigator (i.e. at least +2 pitting oedema and/or an estimated 8 kg gain in weight over baseline over the past 4 weeks) requiring intravenous loop diuretic therapy
• Sufficiently severe oedema to justify treatment by an intravenous infusion of furosemide of 10 mg/hour for at least 48 hours
• Systolic blood pressure >90 mmHg and considered to be haemodynamically stable, in the opinion of the Investigator
• History of left ventricular ejection fraction (LVEF) ≤40% confirmed in the last 18 months
• NT-proBNP >1500 pg/ml or BNP >500 pg/ml
• An eGFR of >30 mL/min/1.73 m2 using the eGFR (mL/min/1.73 m2) = 175 x (Scr)-1.154 x (Age)-0.203 x (0.742 if female) x (1.212 if African American)

Exclusion Criteria:

• Acute coronary syndrome, stroke, or transient ischemic attack (TIA), coronary or peripheral revascularization procedures, valve procedures, OR any major surgical procedure within the previous 6 weeks
• Invasive cardiac investigation and/or treatment (i.e. coronary angiography, percutaneous coronary intervention [PCI] or surgery) or other surgical procedure planned in the next 4 weeks
• Use of intravenous radiographic contrast agent within 72 hours prior to screening or planned use during the study
• Severe, in the investigators opinion, uncorrected valve disease or congenital heart disease as the cause for cardiac decompensation
• Acute mechanical cause of decompensated heart failure such as papillary muscle rupture
• Obstructive or infiltrative cardiomyopathy (e.g. amyloid, sarcoid, etc), suspected acute myocarditis, or heart failure related to an untreated metabolic condition (e.g. haemochromatosis)
• Second or third degree heart block unless the subject has a ventricular pacemaker
• Atrial fibrillation/flutter with sustained ventricular response of >130 bpm
• Placement of a ventricular resynchronization device within the previous 6 weeks
• Treatment or planned treatment with intravenous inotropic agents other than digoxin at any time on this admission
• Receipt of intravenous vasodilator therapy ≤ 6 hours prior to randomization
• The presence of any mechanical assist device or listed for or a history of a heart transplant
• Severe respiratory disease or anticipated need for mechanical respiratory support (i.e. mechanical ventilation)
• Anuric in the previous 24 hours
• Haemoglobin <9 g/dL at screening or planned blood transfusions in the next 30 days
• Serum potassium >5.5 mEq/L
• Marked proteinuria suggestive of nephrotic syndrome
• Estimated GFR (eGFR) as per MDRD equation <30 ml/min
• Serum albumin of < 2.8 g/dL
• Liver enzymes (alanine aminotransferase [ALT] and/or aspartate aminotransferase [AST]) elevation >5 times the upper limit of normal (ULN)
• Total bilirubin >2.0 times ULN in the absence of Gilbert's Syndrome
• Current or planned ultrafiltration, paracentesis, haemofiltration or dialysis