What external influences can a cardiac pacemaker have?
Bertoit, I'm sure you mean well, but your friend should be discussing this kind of concern with his health professionals, not you. Searching the Internet for medical advice can be a greater hazard than the things you seem worried about.
From the Mayo Clinic's patient advice re pacemakers:

Special precautions
It's unlikely that your pacemaker would stop working properly because of electrical interference. Still, you'll need to take a few precautions:

Cellphones. It's safe to talk on a cellphone, but keep your cellphone at least 6 inches (15 centimeters) away from your pacemaker. Don't keep your phone in a shirt pocket. When talking on your phone, hold it to the ear opposite the side where your pacemaker was implanted.

Security systems. Passing through an airport metal detector won't interfere with your pacemaker, although the metal in it could sound the alarm. But avoid lingering near or leaning against a metal-detection system.
To avoid potential problems, carry an ID card stating that you have a pacemaker.

Medical equipment. Make sure all your doctors and dentists know you have a pacemaker. Certain medical procedures, such as magnetic resonance imaging, CT scans, cancer radiation treatment, electrocautery to control bleeding during surgery, and shock wave lithotripsy to break up large kidney stones or gallstones could interfere with your pacemaker.

Power-generating equipment. Stand at least 2 feet (61 centimeters) from welding equipment, high-voltage transformers or motor-generator systems. If you work around such equipment, ask your doctor about arranging a test in your workplace to determine whether the equipment affects your pacemaker.


Devices that are unlikely to interfere with your pacemaker include microwave ovens, televisions and remote controls, radios, toasters, electric blankets, electric shavers, and electric drills.