Certain medical devices have become increasingly complex, and the growing use of wireless technology in these devices has raised concerns about how protected they are against information security risks that could affect their safety and effectiveness. The Food and Drug Admin. (FDA), an agency within the Dept. of Health and Human Services (HHS), is responsible for ensuring the safety and effectiveness of medical devices in the U.S. FDA reviews manufacturers' applications to market medical devices during its premarket review process and monitors devices, once it has approved them, through its postmarket efforts. This report (1) identifies the threats, vulnerabilities, and resulting information security risks associated with active implantable medical devices; (2) determines the extent to which FDA considered information security during its premarket review of certain devices with known vulnerabilities; and (3) determines what postmarket efforts FDA has in place to identify information security problems. Figures and tables. This is a print on demand report.