This drug has been developed to treat Hyponatremia. The primary purpose of this study is to verify the efficacy and safety of seven-day repeated oral administration of tolvaptan at 15, 30, and 60 mg or placebo in patients with Non-hypovolemic Non-acute Hyponatremia secondary to Congestive Heart Failure (CHF), hepatic cirrhosis or Syndrome of Inappropriate Antidiuretic Hormone (SIADH), despite receiving standard therapy. This study is being conducted in China.

Inclusion Criteria (for CHF):

1. Patients with CHF who exhibit edema, jugular venous distention, hepatomegaly, or pulmonary congestion.
2. Non-hypovolemic and Non-acute hyponatremia with a serum sodium < 135mEq/L before randomization.
3. Patients who have taken furosemide at 40 mg/d or more (oral dosing) without alteration of dosage for the 3 days of the observation period.
4. Patients whose body weight has been stable (±1.0 kg) for 2 days prior to commencement of study drug administration.
5. Age:18～80 (when informed consent is obtained)，male or female.
6. In-patient subjects.
7. Informed consent.

Inclusion Criteria (for hepatic cirrhosis):

1. Patients with hepatic edema.
2. Non-hypovolemic and non acute hyponatremia with a serum sodium < 135mEq/L before randomization.
3. Age:18～65 (when informed consent is obtained)，male or female.
4. In-patient subjects.
5. Informed consent.

Inclusion Criteria (for SIADH and others):

1. Patients with SIADH arising from a variety of etiologies.
2. Non-hypovolemic and non acute hyponatremia with a serum sodium < 135mEq/L before randomization.
3. Age:18～80 (when informed consent is obtained)，male or female.
4. In-patient subjects.
5. Informed consent.