Initial Study of Fenoterol as a Treatment for Heart Failure

Background: \- Fenoterol has been used to treat asthma by opening up the airways in the lungs. It also increases the heart rate without significantly increasing blood pressure. This means that it may help improve heart function by boosting the heart's output. Researchers have developed a different form of the drug that may be given to individuals with heart trouble. This new form needs more testing. It is especially important to compare the new form with the original form of the drug used to treat asthma. Objectives: \- To compare how safe and effective two different forms of Fenoterol are in improving heart function. Eligibility: \- Healthy people between 21 and 60 years of age who have no history of heart disease. Design: * People will be screened with a medical history, physical exam, blood and urine tests, and heart function studies. * Those in the study will have two 36-hour inpatient study visits. At each visit, they will have a physical exam and blood and urine tests. They will fast overnight and then receive one of the two forms of Fenoterol first thing in the morning. They will not know whether they are getting the original or the modified form of the drug. After receiving the drug, they will provide frequent blood and urine samples for 24 hours. They will have a final exam before being discharged. * Those who take part in the study will have a followup visit 5 to 7 days after the end of each study visit. They will provide more blood and urine samples and have a physical exam.