Medical radar devices, including ultra-wideband (UWB) devices, for use in assisting and/or guiding cardiopulmonary resuscitation (CPR) by indicating one or more of: compression depth, compression frequency, and a return to spontaneous circulation. The devices and methods described herein may use reflected energy applied to a patients chest to determine cardiac motion and/or chest compression and provide feedback to the person applying the CPR. In some variations the device is incorporated as a part of another resuscitation device, such as a defibrillator or automatic compression device.