 High glucose as well as fluctuations in blood glucose can contribute to severe hospital complications and even death. Studies also suggest that heart failure patients who have high glucose or diabetes do not live as long as patients with normal glucose. Glucose fluctuations have not been well-studied in patients with heart failure. In this study, we will determine whether better control of blood sugar fluctuations in the hospital improve outcomes. We will enroll 80 patients with severe heart failure and divide them into 2 groups. We will use intravenous given through the vein insulin to lower blood sugar levels in group 1, and insulin injections under the skin in group 2. We will determine whether intravenous insulin improves blood markers of inflammation, changes in vital signs, and other tests that predict mortality in patients with heart failure. 