Pacemaker or Defibrillator interrogation is a process for checking on the function of a device to make sure it is working properly and the batteries are in good condition. In this procedure, a doctor/nurse waves a wand connected to a computer over the patient’s chest. The wand and pacemaker communicate wirelessly, allowing the computer to extract data from the pacemaker’s memory. The computer will also check on the pacemaker’s battery life. This is not painful to the patient, although sometimes patients feel lightheaded or strange during a pacemaker interrogation.