A magnetized device used to test an inhibited or triggered type of pacemaker or defibrillator, and cause an inhibited or triggered generator to revert to asynchronous operation. The device is placed on the outside of the patient's thorax over the pacemaker/defibrillator for analysis of the implanted device's function. The magnet will activate the magnet sensitive relay in the pacemaker/defibrillator and will change the function of the implanted device. It is possible to evaluate the function of the implanted device via an electrocardiograph.