Effect of Tolvaptan on Mid- to Long-term Prognosis of Heart Failure Patients

Inclusion Criteria: * Patients from whom informed consent has been properly obtained in writing prior to start of the trial * Patients who have been clinically diagnosed with heart failure * Patients with any of the following conditions or symptoms: lower limb edema, dyspnea, jugular venous distension, hepatomegaly, pulmonary rales, third heart sound, or pulmonary congestion * Patients who have been receiving loop diuretics, thiazide diuretics, or anti-aldosterone diuretics * Male or female patients of age 20 to 85 years inclusive (at time of informed consent) * Patients who, together with their partner(s), are able to use an appropriate method of contraception until 3 months after final trial drug administration * Patients who are able to be hospitalized at the trial site for at least 7 days from the start of trial drug administration Exclusion Criteria: * Patients with a history of hypersensitivity to any ingredient of the drug or to tolvaptan analogues (e.g., mozavaptan hydrochloride) * Patients with anuria * Patients who cannot sense thirst or who have difficulty with fluid intake * Patients with hypernatremia (serum sodium concentration \> institutional upper limit of normal) 5) Female patients who are pregnant, possibly pregnant, or nursing * Patients judged by the investigator or subinvestigator to be inappropriate for inclusion in the trial due to any of the following conditions or symptoms: * Hyponatremia (serum sodium concentration \< 125 mEq/L) * Serious coronary artery disease or cerebrovascular disease * Hyperkalemia * Severe renal disorder * Poorly controlled diabetes mellitus * Severe hepatic disease * Impaired urinary excretion due to urinary stenosis, calculus, or tumor * Cardiac valve disease with significant heart valve stenosis * Malignant tumor of unfavorable prognosis * Patients with suspected hypovolemia * Patients with an implanted circulatory support device * Patients in whom acute cardiac infarction occurred within 30 days prior to the screening examination * Patients who participated in any other clinical trial or postmarketing clinical trial within 30 days prior to the date of informed consent for the present trial * Patients who received tolvaptan within 26 weeks prior to the date of informed consent * Patients who are otherwise judged by the investigator or sub-investigator to be inappropriate for inclusion in the trial