More and more workers are equipped with active medical implants that can interfere with the magnetic fields encountered in the workplace. With occupational exposure limits higher than those for the general population, there is potentially more intense exposure at work. To study the response of active implants to electromagnetic fields encountered in industry, a new in vitro test method was proposed. It consists of exposing the implant to a representative field of occupational exposure using a specific test bench. This new test method was applied to pacemakers, which are by far the most commonly used active medical implant. The tests evaluated the influence of a large number of parameters, such as the direction of the magnetic field, its frequency or the position of the leads, on the functioning of a pacemaker. The three most relevant parameters for assessing the risk are the field amplitude, the field frequency and the detection sensitivity of the cardiac activity depending on the device settings. The study also provided a better understanding of the interaction mechanisms. It was observed that, above a specific field intensity, the device considers the electromagnetic disturbance as a cardiac contraction. This test method can also be applied to other active implants, such as implantable cardioverter-defibrillators or insulin pumps