Guidant Corp. said Friday that it was recalling defibrillators implanted in nearly 50,000 people worldwide because of a flaw that could cause the devices to malfunction.

At least two patients with the devices have died. The Indianapolis-based company said it was advising physicians about the safety of several defibrillator models, which have failed at least 45 times.

The Food and Drug Administration advised patients to see their doctors and said it would not recommend whether individual patients with the recalled devices should have them removed and replaced. Guidant offered to replace some of the defibrillators, but has not said that removal or replacement is necessary.

Implantable defibrillators are intended to sense an irregular heart rhythm and shock the heart back into correct beating.

The recall includes about 38,000 devices used by patients in the United States.

Guidant came under fire this spring after reports that it failed to alert physicians about potential problems with the Ventak Prizm 2 DR model defibrillator.

Friday's recall includes the Prizm 2 DR, the Contak Renewal and Contak Renewal 2, the Ventak Prizm AVT, Vitality AVT, Renewal 3 AVT and Renewal 4 AVT ICDs. The company said about 63,000 of the devices had been implanted, of which nearly 50,000 are still in use.

Guidant said patients implanted with those devices should continue to see their doctors at three-month intervals and any patients who recently received a defibrillator shock should consult with their physician.

The company said a programming change can be performed for the Prizm AVT, Vitality AVT and Renewal AVT devices at a physician's office to reduce the risk of a short circuit, while defective Prizm 2 DR and Contak Renewal devices will be replaced at no charge.

"Patient safety is paramount and our highest priority," Guidant chief executive Ronald W. Dollens said in a news release. "Guidant takes seriously its responsibility to create the most reliable products and services, enhance patient outcome and limit adverse events to patients."

Earlier this month, Guidant stood by its decision to continue selling the Prizm 2 DR for months after a potential flaw prompted a redesign, saying the original device was still reliable.

In April, the company told doctors that the Prizm 2 DR defibrillator had failed in a small number of cases because of an electrical flaw. It also said that it had fixed the flaw in devices made after mid-2002.

No failures in the Prizm 2 DR have been reported since April 2002. The faulty Contak Renewal defibrillators were manufactured on or before Aug. 26, 2004, Guidant said.

A Pennsylvania man sued Guidant on June 1, claiming the company is financially liable to all patients implanted with one of its heart defibrillators because it did not tell them the devices could short-circuit. Lawyers for John Brennan said they hoped to make the legal complaint into a class-action lawsuit.

Guidant shareholders in April voted overwhelmingly in favor of a planned $25.4 billion acquisition by Johnson & Johnson Inc. The merger, which needs regulatory approval in the United States and Europe, would be the largest business deal in the 119-year history of New Brunswick, N.J.-based Johnson & Johnson.

Johnson & Johnson has said it expects to complete the acquisition during the third quarter. It did not respond to a request for comment.