Magnets may interfere with the operation of pacemakers and implantable cardioverter defibrillators (ICDs), according to a study published in the December 2006 edition of “Heart Rhythm.”
A release from the Heart Rhythm Society reports that researchers found that while common magnets for home and office use with low magnetic strength posed little risk, stronger magnets made from neodymium-iron-boron (NdFeB) may cause interference with cardiac devices and pose potential hazards to patients. NdFeB magnets are increasingly being used in homes and office products, toys, jewelry and even clothing.
“Physicians should caution patients about the risks associated with these magnets,” says Thomas Wolber, a cardiologist at the University Hospital of Zurich in Switzerland and lead author of the study. “We also recommend that the packaging include information on the potential risks that may be associated with these types of magnets.”
Two spherical magnets of eight and 10 millimeters in diameter and one necklace made of 45 spherical magnets were tested on 70 patients, 41 with pacemakers and 29 with ICDs. Magnetic interference was observed in all patients. The cardiac devices resumed normal function after the magnets were removed.
“This study is timely and important to attract the attention of both the public and the medical profession about the potentially serious health consequences of magnets used in decoration products... for an ICD patient, the magnet interference can be fatal,” writes Huagui Li, M.D., a cardiologist at the Minnesota Heart Clinic in Edina, MN, in an accompanying “Heart Rhythm” editorial.
Dr. Li concludes that manufacturers who use magnets should be required to put warning labels on their products for optimal patient safety.
May 06, 2026 
