Abstract: Implantable Cardiac Defibrillators (ICDs) are at the forefront of preventing sudden death in patients suffering from ventricular arrhythmias. ICDs have evolved into complex Cyber-Physical Systems (CPS) which tightly sensing, hardware, and software to diagnose arrhythmias based on electrogram signals and control cardiac excitation. These devices are life-critical, yet the Verification and Validation (V&V) techniques used for establishing their safety have remained informal, and rely largely on extensive unit testing.