question

Any electronic device emits electromagnetic radiation/Fields (EMF) and also can be susceptible to outside sources of EMF. This is why there are rules, regulations and testing that devices sold must pass. EMC, CE and other regulations are there to verify the relative safety of these sorts of things.
Also understand that these fields quickly decay away from the source. So I would not advise taking a nap on top of an MPPT but otherwise I personally wouldn't worry about coming near an active MPPT or inverter for a short period of time.
However, Don't take my advice! I may not know what I am talking about. I would contact the manufacturer of the auto-defib device and ask them if they are aware of any specific situations with solar power electronics that could cause problems.
Maybe you can expand your question? Do you have one of these devices and are interested in installing your own solar system? Are you planning on having a verified installer installing a system? This may impact the answer and others could probably provide better advice.

Thank you for your reply @Eric Tarkleson . As soon as I posted this question, the client got confirmation from the cardioverter-defribrillator that none of the Victron equipment should interfere with the device, provided one limits prolonged contact.