U.S. regulators said Thursday they had received 21 reports of device failures, including three deaths, linked to some Guidant Corp. (GDT) implanted heart defibrillators as of Oct. 7.

The Food and Drug Administration (search) said six of the cases had been reported after the agency issued a public health advisory on July 14. The problems occurred with Guidant's Contak Renewal (search) and Renewal 2 devices.

"You should take these failures into account as you continue to follow the patients who retain either device," the FDA said in a note to doctors posted on the agency Web site at http://www.fda.gov/cdrh/safety/101305-guidant.html

According to information on Guidant's Web site, the company disclosed the same figures in a report posted there on Sept. 19.

Guidant has reported problems with several implanted defibrillator and pacemaker models during recent months.

Shares of Indianapolis-based Guidant, which is being acquired by Johnson & Johnson (JNJ), fell 42 cents, or 0.59 percent, to $70.90 in afternoon trading on the New York Stock Exchange.