A Study of Two Doses of Intravenous NATRECOR hBNP (Nesiritide) in Patients With Worsening Congestive Heart Failure Who Have Difficulty Breathing at Rest

Inclusion Criteria: * History of chronic congestive heart failure (CHF) * symptomatic, decompensated CHF for which intravenous therapy is deemed appropriate for the hospitalized patient * documentation of pulmonary capillary wedge pressure (PCWP) \>= 18 mm Hg, Cl \<= 2.7 mL/min/m² and systolic blood pressure \>= 90 mm Hg with consistent baseline hemodynamic measurements. Exclusion Criteria: * Had a myocardial infarction within the previous 48 hours or unstable angina * stroke within the previous 3 months or other evidence of significantly compromised central nervous system perfusion * has significant valvular stenosis hypertrophic, restrictive or obstructive cardiomyopathy, constrictive pericarditis, primary pulmonary hypertension, biopsy-proven active myocarditis, or complex congenital heart disease * receiving ongoing treatment with an intravenous vasostrictive agent for this episode of decompressed CHF that could not be discontinued for an appropriate washout period to permit the reassessment of baseline hemodynamic and clinical status prior to initiating drug study * clinical status so unstable that the subject can not tolerate placement of a Swan-Ganz catheter.