Ultrasound is a technique that can provide images of the blood vessels such as arteries. The size of the arteries, such as the main blood vessel in the arm, can change under different conditions. Using ultrasound we can see how arteries change with movement or even drugs. We want to use ultrasound to see how blood vessels look in patients with Congestive Heart Failure (CHF) and to also see how a drug called Spironolactone, commonly prescribed for patients with this disease, effects blood vessel function in patients with congestive heart failure. This information may be used to change the standard of care for patients with heart failure especially if we show that Spironolactone has a positive effect on vessel function in patients with CHF.