Guidant Corp. (GDT) on Monday warned physicians that replacements might be needed for nine pacemaker models made between 1997 and 2000, of which some 28,000 remain implanted in patients worldwide.

The Indianapolis-based company, which last month recalled almost 109,000 defibrillators, released a warning that says a sealing component in the pacemakers has degraded in some cases, resulting in higher-than-normal moisture in the devices and possible malfunction.

The company said about 78,000 of the devices were distributed, with about 18,000 of them remaining in U.S. patients.

Guidant said that it has identified 69 failures among the pacemakers — all after they had been used for at least 44 months. The models include: Pulsar Max, Pulsar, Discovery, Meridian, Pulsar Max II, Discovery II, Virtus Plus II, Intelis II, and Contak TR.

The company told physicians they should consider replacing the pacemakers for patients who are dependent on the devices, which send electrical pulses to the heart to regulate its rhythm.

Several patients have lost consciousness or developed possible heart failure, the company said. The statement reported the death of one person whose pacemaker may have failed, but Guidant said that the device was not returned for testing and that its role could not be confirmed.

Food and Drug Administration (search) spokeswoman Julie Zawisza said the agency was evaluating Guidant's warning. Guidant said the FDA may classify the warning as a recall. The company issued two safety warnings last month for 11 models of defibrillators that were later classified by the FDA as recalls.

Defibrillators are also implanted devices; they shock the heart back into rhythm. Almost 88,000 of the Guidant devices that were recalled remain implanted worldwide.

The company said it would replace the pacemakers at no charge through the end of the year, even though the warranty on many has expired. Guidant will also reimburse patients up to $2,500 for medical expenses.

Shares of Guidant fell $1.15 to $68.26 on the New York Stock Exchange; they have traded in a 52-week range of $49.95 to $75.15.

Guidant shareholders in April voted to accept an offer from Johnson & Johnson (JNJ) of $76 per share in cash and stock in a $24.5 billion deal that is still pending. Telephone calls to New Brunswick, New Jersey-based Johnson & Johnson weren't immediately returned.

A.G. Edwards & Sons analyst Jan Wald said Guidant's newest warning follows continued internal scrutiny about potential malfunctions in its products.

"I think it's a company going through their files," he said. "They've gone through their defibrillator product line. Now they're going through their pacemaker product line."

Wald said he did not believe Monday's announcement would jeopardize the Johnson & Johnson deal. Guidant's second-quarter earnings are to be released Thursday.