Radiology exams like x-ray or computed tomography (CT)?
A cardiac device will not be affected by X-rays. Therefore, no precautions will be needed in case of a radiology exam like Chest X-ray or CT scan.
Radiation therapy, mostly used for cancer therapy, can very rarely affect pacemakers or ICD function, depending on the energy dose and the targeted region. If you need radiation therapy, you should inform your treating physician about your cardiac device. Your physician will then evaluate the best strategy how to manage. Usually, the cardiac device will require more intensive controls during the course of radiation therapy.
Magnetic resonance imaging (MRI)
MRI uses a strong electromagnetic field for scanning. This electromagnetic field can affect pacemakers or ICDs. Even though a lot of manufacturers provide MR-conditional pacemakers and ICD, MR scans still require some caution in patients with cardiac devices. If you need an MRI scan, talk to your radiologist/cardiologist and ask for the best strategy.
Other medical procedures (incl. dental procedures, TENS, lithotripsy)
If you need any medical procedure, you should inform the treating physician that you have a pacemaker or ICD. Most medical procedures will be possible even with an implanted device, but some may need special precautions when performing the procedure. Dental procedures are usually possible without further precautions. Surgery should be aware of the device when using electrocautery. TENS (transcutaneous electrical nerve stimulation), which is used to reduce pain and muscle spasm in different medical conditions, is not recommended for patients with pacemaker or ICD. A lithotripsy is possible. Talk to your treating physician for further details on your specific procedure.
Cardioversion (for example, in case of atrial fibrillation)
Like for other medical procedures, discuss with your treating physician that you have a pacemaker or ICD. A cardioversion is possible in pacemaker patients and can be done even internally in patients with an ICD. Usually, a device interrogation is performed before and after the cardioversion.
Many manufacturers of cardiac devices provide more detailed overviews and instructions for patients: