The study involving 26 volunteers with defibrillators found "magnet mode" was triggered in 30 percent of patients who put the tablet on their chest. The iPad2 didn't interfere with four pacemakers or a loop-recorder, which were also tested. Walter Chien, a cardiac electrophysiologist, helped his daughter coordinate the patient testing.
Medtronic Inc., the leading manufacturer of defibrillators, said its testing hasn't found any risks from iPad technology when used according to the manufacturer's instructions. The Minneapolis-based company does tell patients to avoid placing any magnets near the area where their devices are implanted.
"The presentation at Heart Rhythm 2013 is a good reminder for patients to remain vigilant on new technology and its accessories and maintain a distance of six inches between an iPad and an implanted pacemaker or ICD," the company said in a statement.
Most defibrillators will turn back on once the magnet is no longer affecting the device. Some, however, remain off until the magnet is reapplied or the device is turned back on manually, the younger Chien said. Patients should be told about the risk and doctors should check the devices to see if they have been inadvertently turned off by magnets, she said.
Chien said she received an iPad2 for her birthday in August 2011. She was struck at the time by the number of older customers taking a class on how to use the device at the company store and, given her father's specialty, wondered if there could be a connection between the iPads and their heart devices.
"I don't think anyone really knows about the risks," Chien said.
The results are important because they can help raise awareness of the danger in a very specific setting, said Day, the heart meeting official, in a telephone interview. "Defibrillator patients can still buy Apple products," he said. "Just don't put them on your chest."