Study to Evaluate Cardiac Hemodynamics and Safety of SLV320 in Subjects With Congestive Heart Failure

Inclusion Criteria: * history of chronic, symptomatic, mild to severe (NYHA Class II-IV) CHF for at least three months requiring treatment with diuretics and with documented systolic dysfunction * on stable doses of their individually optimized medication regimen for at least one week prior to enrollment Exclusion Criteria: * required hospitalization (for cardiovascular disease) or adjustment of background medications for CHF * orthostatic hypotension or symptomatic orthostasis * sitting systolic or diastolic blood pressure \< 90 mmHg * 2nd or 3rd degree atrio-ventricular block or sick sinus syndrome * heart rate of \< 50 or \> 110 bpm on the ECG * transplanted heart * heart failure due to primary valvular disease (unless surgically corrected), obstructive cardiomyopathy, pericardial disease, cor pulmonale or congenital heart disease * hemodynamically significant left ventricular outflow tract obstruction