May I ask what type of medical device it is?
If it is a pacemaker, interferences are a very rare eventuality and from a brief review of the studies carried out in this regard, it is highlighted that interference is more likely to occur in cases where both devices are not technologically advanced. Furthermore, this electrical interaction does not always have a practical consequence that impacts cardiac activity.
It is sufficient to follow some simple precautions to avoid the risk of interference. It is good practice to keep the mobile phone at least 15 cm away from the pacemaker implant site. For example, do not keep the mobile phone in the shirt pocket if the pacemaker is implanted in the chest or in the belt if it is implanted in the abdomen. It is also better to use the headset during conversations, or the speakerphone, alternatively to converse with the ear opposite the side where the pacemaker is implanted.