This is a single center, double-blinded, crossover, placebo-controlled pilot study to evaluate the effects of nesiritide in patients with chronic heart failure. This study will only take place at the University of Chicago Hospitals. It is double-blinded, which means that the neither subject nor their study doctor will know which study drug the subject will receive. However, in an emergency, this information can be obtained quickly. The study is placebo-controlled, which means subjects will not receive study drug at some point during the study; however because it is a cross-over study, subjects will be receiving nesiritide at some point in the study. Subjects will receive the study drug nesiritide for six out of the 12 weeks of the study—either the first six weeks or the last six weeks.