Warning about magnetic interference between breast tissue expanders with magnetic ports and implantable cardioverter-defibrillators (ICDs) or pacemakers – Letter to Health Care Providers

March 8, 2016

Dear Breast Surgeons, Cardiac Electrophysiologists, Cardiologists, and Plastic Surgeons:

The FDA is aware of reports of magnetic interference between breast tissue expanders with magnetic injection ports and either implantable cardioverter-defibrillators (ICDs) or pacemakers in patients, interfering with the functioning of these cardiac devices. The FDA analyzed peer-reviewed literature, device labeling, adverse event medical device reports, and information from ICD manufacturers, health care organizations, and professional societies. At this time, the FDA believes that there is a very small population at risk, as it is generally uncommon for patients with an ICD or pacemaker to have breast reconstruction. However, we are alerting health care providers to this risk, so you can help prevent it.

ANALYSIS OF THE PROBLEM

ICDs are implantable devices used to correct life-threatening heart rhythm abnormalities in patients at risk for sudden cardiac death. Pacemakers are small devices placed in the chest or abdomen to help regulate abnormal heart rhythms. Breast tissue expanders are temporarily used (no more than six months) to prepare patients for reconstructive breast surgery after mastectomy, and to treat under-developed breasts or other soft-tissue deformities. Some breast tissue expanders have a magnetic injection port to guide the surgeon when injecting saline fluid to expand them.

In patients with a magnetic-port breast tissue expander who also have an ICD or pacemaker, the magnetic port can come close enough to the cardiac device to cause magnetic interference. This interference causes the ICD or pacemaker to enter “magnet mode." ICDs in magnet mode will not deliver life-saving shocks or anti-tachycardia pacing therapy, which can be life-threatening to the patient if a dangerous abnormal heart rhythm were to occur. Patients might hear an electronic tone indicating that the device is entering magnet mode, depending on the ICD make and model. When a pacemaker enters magnet mode, the device continuously paces without sensing the patient’s own heart rhythm, which can result in symptoms (such as irregular heartbeats), abnormal heart rhythms, or rarely, more serious patient harm. The likelihood of magnetic interference (entering magnet mode) varies depending on the type of implant and the proximity of the breast tissue expander to the ICD or pacemaker.

Device labeling for ICDs, pacemakers, and breast tissue expanders includes warnings about the potential for magnetic interference. Magnetic-port breast tissue expanders’ labeling includes a contraindication for use in patients who already have implanted devices that would be affected by a magnetic field, such as ICDs or pacemakers. ICD and pacemaker labeling includes warning statements about magnets, magnetic fields, and interference. ICD labeling also provides information about how a health care provider can change the function of the device if there is a chance it will come in contact with a magnet. In some cases, health care providers can reprogram the ICD for a patient with an ICD and breast tissue expander already in place to reduce the possibility of future interference.

While magnetic-port breast tissue expanders are commonly used to prepare women for breast reconstruction, there are alternative expanders that can be used in patients with ICDs or pacemakers. These alternatives include breast tissue expanders with a non-magnetic port, a non-magnetic metal disc or a remote port.

RECOMMENDATIONS

Avoid, whenever possible, implanting a magnetic-port breast tissue expander in a patient with a pacemaker or an ICD, due to a small risk of asynchronous pacing or suspension of anti-tachycardiac therapy.
Review the device labeling and discuss all available treatment options, including the risks and benefits of each, with your patients before deciding the best treatment approach:
- For patients with an ICD or pacemaker implanted prior to considering breast reconstruction, device labeling recommends minimizing exposure to magnetic interference. If a patient has an ICD or pacemaker, a non-magnetic reconstructive option should be used.
- When a patient with an implanted magnetic breast tissue expander requires the placement of an ICD or pacemaker, careful consideration should be given to choice of cardiac device, location and timing of implantation, the possible need for more frequent cardiac device checks, and whether a different breast tissue expander might be used.
Warn patients who have a magnetic-port breast tissue expander and an ICD or pacemaker of the possibility of magnetic interference. Tell patients who have an ICD that emits an electronic tone when the device experiences interference to seek care if they hear the tone.
Report any adverse events that come to your attention. Voluntary reports can be submitted through MedWatch, the FDA Safety Information and Adverse Event Reporting program. Device manufacturers and user facilities must comply with the applicable Medical Device Reporting (MDR) regulations. Health care personnel employed by facilities that are subject to FDA's user facility reporting requirements should follow the reporting procedures established by their facilities. Prompt reporting of adverse events can help the FDA identify and better understand the risks associated with medical devices.

We have enclosed below additional resources related to the issue:

If you have questions about this communication, please contact the Division of Industry and Consumer Education (DICE) at [email protected], 800-638-2041 or 301-796-7100.

Sincerely,

/s/

William Maisel, MD, MPH
Deputy Center Director for Science
Center for Devices and Radiological Health
U.S. Food and Drug Administration