Study to Evaluate the Effects of Oral Administration of Lixivaptan in Patients With Congestive Heart Failure

Inclusion Criteria: * Ability to understand the purpose and risks of the study and to provide signed and dated informed consent. * Men and women aged 18 years or older. * History of chronic CHF defined as requiring standard HF treatment (including diuretics) for a minimum of 30 days. * Documented LVEF by any method within 12 months prior to screening. * The patient has clinical evidence of volume overload at the time of inclusion with at least one of the following: * Dyspnea * Pulmonary congestion (rales) * Peripheral edema * Increased jugular venous pressure and/or hepatic congestion with ascites * Chest x-ray consistent with CHF * Plasma brain natriuretic peptide (BNP) ≥150 pg/mL or N-terminal prohormone brain natriuretic peptide (NT pro-BNP) ≥450 pg/mL Exclusion Criteria: * Women who are pregnant (positive pregnancy test), breastfeeding, or who will not adhere to the reproductive precautions as outlined in this protocol and in the informed consent form (ICF). * Sustained (three blood pressure measurements over 1 hour) systolic blood pressure \<90 mmHg at Screening or Day 0. * ST segment elevation myocardial infarction or stroke within 30 days prior to Screening. * Hemodynamically destabilizing cardiac arrhythmia within 30 days prior to Day 0. * Clinically significant valvular disease. * Known clinically significant obstructive, restrictive, or hypertrophic cardiomyopathy. * Cardiac surgery or percutaneous coronary intervention within 30 days prior to Day 0. * Major surgical procedure within 7 days prior to Day 0. * Likely to undergo cardiac transplantation, left ventricular assist device (LVAD) or other device implantation, or other cardiac surgery within 3 months after Screening. * Placement of implantable cardioverter defibrillator or cardiac resynchronization therapy device within 60 days prior to Day 0. * CHF due to uncorrected thyroid disease, active myocarditis, or known amyloid cardiomyopathy. * Presence of any clinically significant (as determined by the Investigator) endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, oncologic, and/or other major disease that might interfere with safe and compliant participation in this study. * Screening laboratory findings as follows: * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 3 times the upper limit of normal * Total bilirubin \>2.0 mg/dL * Serum creatinine \>3.0 mg/dL * Hemoglobin \<9.0 g/dL * Uncontrolled diabetes mellitus as defined by the Investigator (e.g., glycosylated hemoglobin \[HbA1c\] \>9%). * History of chronic drug/medication abuse within the past 6 months; or current alcohol abuse. * Co-morbid condition with an expected survival of less than 3 months. * Known allergy to any vasopressin antagonist or any condition for which treatment with a vasopressin antagonist may present undue risk to the patient. * Current or recent administration (within 7 days of Day 0) of prohibited medications as listed in Section 8.6.4 . * Participation in any other investigational study of drugs or devices within 30 days prior to Screening.