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Cardiac Resynchronization Therapy (CRT) device support

Using household appliances and tools

Understanding electromagnetic safety

Tens of thousands of patients worldwide rely on Boston Scientific technology for life-changing medical solutions, implants, and pain relief therapies. 

The goal of Cardiac Resynchronization Therapy (CRT) is to get you back to the things you enjoy in everyday life. It’s important to understand the facts about electromagnetic interference and your device to stay safe in every situation.

All items that use electricity or transmit wireless signals have invisible electromagnetic fields around them that may temporarily interfere with your CRT device. This is called electromagnetic interference, or EMI for short.

Boston Scientific CRT-D and CRT-P devices are designed to work properly around most appliances and tools. However, some appliances and tools may impact how your device works. While these effects are usually temporary, we recommend using the following guidelines for safe interaction with many common household items.

Your device has built-in features that protect it from interference from most electrical or wireless household items. Note, some electrical and wireless items must be kept a certain distance away from your implanted device to avoid interaction with your device. 


Know the sound

A CRT device may deliver a beeping sound to let you know you are near a large magnet or source of EMI.


Safety ratings

Avoid use

Use with caution

Safe to use

Household tools that are not safe for use

The following items are not safe to use if you have a CRT-P or CRT-D device:

Avoid use

Avoid use

Avoid use

Avoid use

Household tools that are safe to use at a distance (use with caution)

If you use any of the following items, it’s important to keep them the recommended distance away from your implanted device to avoid interaction.  

Items that should not be placed directly over your CRT-P or CRT-D, but are otherwise safe to use

Use with caution

Use with caution

Use with caution

Use with caution

While portable MP3 players should not interfere with your pacemaker, the headphones or earbuds should be stored at least 6 inches (15 cm) away from your pacemaker. You should avoid draping the headphones around your neck.

Items that should remain at least 6 inches (15 cm) away from your CRT-P or CRT-D

Use with caution

Use with caution

Use with caution

It is safe to use headphones and earbuds, but you should refrain from draping them around your neck and from storing them in a breast or other shirt pocket.

Use with caution

Items that should remain at least 12 inches (30 cm) away from your CRT-P or CRT-D:

Use with caution

Use with caution

Use with caution

It is safe to use headphones and earbuds, but you should refrain from draping them around your neck and from storing them in a breast or other shirt pocket.

Use with caution

Use with caution

Use with caution

Use with caution

Use with caution

Use with caution

Use with caution

Items that should remain at least 24 inches (60 cm) away from your CRT-P or CRT-D

Use with caution

Use with caution

Use with caution

Avoid leaning over running motors and alternators of a running vehicle. Alternators create large magnetic fields that can affect your implanted device. However, the distance required to drive or ride in a vehicle is safe.


Household tools that are safe under normal use

The following household items are generally safe to use with a CRT-P or CRT-D as long as they are in good working condition and used as intended:

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Consult with your doctor before using a hot tub. While a hot tub will not harm your implanted device, your medical condition may not permit this activity.

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

PDAs that also function as cell phones should be kept at least 6 inches away from your CRT-P or CRT-D.

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use

Safe for use


Using cell phones safely

Your cellular phone is a source of EMI and could affect your CRT-P or CRT-D's operation. This interaction is temporary, and moving the phone away from your device will return it to proper function. To reduce the chance of interaction, follow these precautions:  

  • Maintain a distance of at least 6 inches (15 cm) between the cell phone and your device. If the phone transmits more than 3 watts, increase the distance to 12 inches (30 cm) 
  • Hold the cellular phone to your ear on the opposite side of your body from your CRT-P or CRT-D 
  • Do not carry a cell phone in a breast pocket or on a belt if that places the phone within 6 inches (15 cm) of your device 

These precautions apply only to cell phones, not to household cordless phones. However, you should avoid placing your household cordless phone receiver directly over your CRT-P or CRT-D device.


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TERMS OF USE: The information provided on the Electromagnetic (EMI) Guide should not be considered the exclusive or only source for this information. The table lists a general category of items only and is not intended to be an exhaustive list. The recommendations and precautions may be based on information provided by the manufacturers of the items in question, and specific items within a category may function differently. It is best practice to consult the original manufacturer of the item with potential EMI to verify any specific guidance concerning operation and compatibility with implantable devices. If at any time there is a question about the function and potential for Electromagnetic Compatibility, contact the manufacturer of the item in question for further information. At all times, it is the responsibility of the licensed healthcare professional to exercise medical clinical judgment in a particular circumstance. 

The information provided is not intended to be used for medical diagnosis or treatment or as a substitute for professional medical advice. The recommendations and precautions contained in this document apply to device function of Boston Scientific Cardiac Rhythm implantable devices. Specifically device susceptibility to electromagnetic interference. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Important Safety Information

Cardiac resynchronization therapy pacemakers (CRT-P) and defibrillators (CRT-D) are designed to treat heart failure patients who may or may not have symptoms or who may have symptoms despite the best available drug therapy. They are also designed to help your heart pump more effectively and meet your body’s need for blood flow.  These devices are sensitive to strong electromagnetic interference (EMI) and can be affected by certain sources of electric or magnetic fields. With all medical procedures there are risks associated.  In regard to an implanted ICD, the risks include but are not limited to inappropriate shock, lead moves out of place, loss of stimulation capability, allergic reaction, fluid underneath the skin, and infection.  In rare cases device failure or death can occur.  Be sure to talk with your doctor so that you thoroughly understand all of the risks and benefits associated with the implantation of this system.  To obtain a copy of the device Patient Handbook for more detailed device safety information, go to www.bostonscientific.com,  or you can request a copy by calling 1-866-484-3268 or writing to Boston Scientific, 4100 Hamline Ave. N., St. Paul, MN  55112. 

Device Quality and Reliability

It is Boston Scientific’s intent to provide implantable devices of high quality and reliability. However, these devices may exhibit malfunctions that may result in lost or compromised ability to deliver therapy. Refer to Boston Scientific’s CRM product performance report on www.bostonscientific.com for more information about device performance, including the types and rates of malfunctions that these devices have experienced historically. While historical data may not be predictive of future device performance, such data can provide important context for understanding the overall reliability of these types of products. Also, it is important that you talk with your doctor about the risks and benefits associated with the implantation of a device.

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