 During your participation on this study, you will have a physical exam, routine blood tests and chest x-ray at Weeks 2, 6, and 10. At Weeks 6 and 10, you will also have a CT scan. You will have an ECG at Weeks 1, 2, 4, and 8. Your doctor may decide to have additional ECGs to monitor your condition or if you experience a heart rate of less than 50 at any time during study participation. You will also be asked to complete 2 questionnaires about the quality of your life and any shortness of breath you are experiencing. You will complete these questionnaires at home and return them to the research staff at each clinic visit. You will be asked to record your weekly blood pressure for the first 6 weeks of study treatment. The study doctor or research nurse will review the log at each clinic visit. 