A federal judge who dismissed hundreds of lawsuits filed against Medtronic Inc. said Monday he won't step aside, even though his son works for a Minneapolis law firm that does extensive legal work for the medical technology giant.

Attorneys representing hundreds of patients who claimed they were harmed by a heart device made -- and later recalled -- by the Fridley-based company have called on U.S. District Judge Richard Kyle to recuse himself from the case.

Kyle's son, Richard Kyle Jr., works for the law firm Fredrikson & Byron, which does millions of dollars worth of corporate work for Medtronic. In his ruling Monday, the elder Kyle noted that his son works on criminal defense cases and "does not now represent, and has never previously represented, Medtronic."

Earlier this year, Kyle dismissed hundreds of cases filed in federal court by patients who claimed they were harmed by Medtronic's Sprint Fidelis defibrillator lead, an insulated wire that connects the device to the heart. (The stopwatch-sized device shocks an errantly beating heart back into rhythm.)

In October 2007, Medtronic recalled the wire, saying a small number could fracture, rendering the device useless or, conversely, electrically shock patients repeatedly. At the time of the recall, the company attributed five deaths to the malfunctioning lead.

Soon, hundreds of patients began filing suits against Medtronic, claiming product liability, negligence, fraud and breach of contract. About 700 cases were consolidated in district court in St. Paul.

Kyle dismissed the cases brought in his court on the basis of a 2008 Supreme Court ruling that if federal regulators approved a medical device -- in this case, the Food and Drug Administration -- then product liability lawsuits could not be filed under state law, a legal doctrine known as preemption.

Shortly after, lawyers representing consumers argued that Kyle is biased because his son is a shareholder with Fredrikson & Byron. Kyle rejected that argument, calling it "little more than a hypothetical house of cards" offering "nothing more than the gossamer strands of speculation and surmise to support it."

Daniel Gustafson, the lead lawyer representing the plaintiffs in the Sprint Fidelis case, said no decision has been made on an appeal.

But now the status of the Supreme Court ruling regarding medical device litigation is a bit murky. Last week, the high court held that injured consumers could sue drug companies in a case involving pharmaceutical giant Wyeth. (The two cases involved different legal issues.)

Last week Democrats in Congress said they would move to overturn the decision. Energy and Commerce Committee Chairman Henry Waxman, D-Calif., said that the FDA should not be considered the final arbiter of medical product safety, and that state courts help bolster federal regulation of devices. Hearings on the issue are expected in coming weeks.

Janet Moore • 612-673-7752