This project represents a cross-disciplinary collaborative research effort on developing rigorous, closed-loop approaches for designing, simulating, and verifying medical devices. The work will open fundamental new approaches for radically accelerating the pace of medical device innovation, especially in the sphere of cardiac-device design. Specific attention will be devoted to developing advanced formal methods-based approaches for analyzing controller designs for safety and effectiveness; and devising methods for expediting regulatory and other third-party reviews of device designs. The project team includes members with research backgrounds in computer science, electrical engineering, biophysics, and cardiology; the PIs will use a coordinated approach that balances theoretical, experimental and practical concerns to yield results that are intended to transform the practice of device design while also facilitating the translation of new cardiac therapies into practice. The proposed effort will lead to significant advances in the state of the art for system verification and cardiac therapies based on the use of formal methods and closed-loop control and verification. The animating vision for the work is to enable the development of a true in silico design methodology for medical devices that can be used to speed the development of new devices and to provide greater assurance that their behaviors match designers' intentions, and to pass regulatory muster more quickly so that they can be used on patients needing their care. The scientific work being proposed will serve this vision by providing mathematically robust techniques for analyzing and verifying the behavior of medical devices, for modeling and simulating heart dynamics, and for conducting closed-loop verification of proposed therapeutic approaches. The acceleration in medical device innovation achievable as a result of the proposed research will also have long-term and sustained societal benefits, as better diagnostic and therapeutic technologies enter into the practice of medicine more quickly. It will also yield a collection of tools and techniques that will be applicable in the design of other types of devices. Finally, it will contribute to the development of human resources and the further inclusion of under-represented groups via its extensive education and outreach programs, including intensive workshop experiences for undergraduates.