"Medtronic, Inc ... has voluntarily suspended worldwide distribution of the Sprint Fidelis family of defibrillation leads because of the potential for lead fractures," the Minneapolis-based company said in a statement.
"The company recommends against new implants of the leads" -- electrical wires that link a patient's heart to a defibrillator implanted in the chest, it added. Some 268,000 of the leads have been implanted worldwide.
"Based on current information regarding the 268,000 implanted leads, Medtronic has identified five patient deaths in which a Sprint Fidelis lead fracture may have been a possible or likely contributing factor," it said.
A defibrillator applies an electric shock to the heart to restore it to its proper rhythm if it beats irregularly. If it fractures, it may deliver a painful shock when one is not needed, or may fail to fix the heart beat.
The company, citing specialists, warned patients against seeking to have the devices replaced, however, since "the risks of removal or insertion of another lead exceed the small risk to patients of a lead fracture."
It advised patients who may have a Fidelis lead to see their doctors, whom it has issued with guidance on reprogramming the devices and monitoring their performance. The alert does not affect Medtronic pacemakers.
"Medtronic has acted responsibly to address concerns about the possibility of lead fractures and to minimize harm to patients," Kevin Hackett of the company's Independent Physician Quality Panel said in the statement.
"The physician panel has reviewed Medtronic's data and believes they are taking the correct action."
Medtronic is the world's biggest seller of such cardiac devices. Like other heart device makers, it has had to issue alerts and recalls over malfunctions in the past, reports said.
The New York Times reported that US Vice-President Dick Cheney has a Medtronic defibrillator, but added that it was implanted in 2001 -- before the Fidelis lead was introduced.