The recall is the latest in a string of product problems Boston Scientific inherited when it bought Guidant Corp. in April for $27 billion.
Boston Scientific said it was asking its sales force and managers of hospital inventories to return some units of six models of defibrillators and pacemakers that have potentially faulty low-voltage capacitors, which are used to store electrical charges.
The announcement sent shares of Boston Scientific down over 5 percent in morning trading to their lowest level in nearly four years.
The Natick-based company did not specify how many units were being returned, saying the recall involved a "subset" of certain models of devices that are designed to maintain a steady heart rhythm. About 27,000 devices that could have the problem had already been surgically implanted in patients.
Boston Scientific spokesman Paul Donovan said a letter the company sent to doctors did not recommend surgeries to remove potentially faulty devices.
"Instead, we're recommending that people see their doctors at the earliest opportunity," Donovan said.
The company was advising doctors to check for signs of a malfunctioning capacitor, such as prematurely dead batteries or a device that stops working as intended to restore a normal heart rhythm.
The affected devices all were manufactured by Indianapolis-based Guidant, which Boston Scientific acquired April 21. Devices affected include Insignia and Nexus brand pacemakers, Contak Renewal TR/TR2 cardiac resynchronization pacemakers, and Ventak Prizm 2, Vitality, and Vitality 2 cardioverter defibrillators.
Boston Scientific said the capacitor that triggered the recall came from an outside supplier.
Of the 27,000 implanted devices that may have the flaw, problems have turned up in five patients, Boston Scientific said. None involved deaths, but in two cases pacemaker patients temporarily became unconscious.
In four cases, patients required surgery to replace devices. In another, the malfunction was discovered when the device was being implanted.
Shares of Boston Scientific fell 97 cents to $17.29 in midmorning trading on the New York Stock Exchange. The company's shares last traded in that range in the fall of 2002.
The company's stock has lost about a third of its value since December, when Boston Scientific launched a bidding war against Johnson & Johnson to purchase Guidant.
Since June 2005, Guidant has issued safety warnings or recalled more than 88,000 defibrillators, and has recalled or issued warnings on about 200,000 pacemakers. Boston Scientific also inherited liability lawsuits connected with the products, which have been linked to at least seven deaths.
Guidant had been criticized for failing to notify doctors, patients and regulators of the extent of its product problems, and Boston Scientific has vowed to do a better job.