Readers may recall Dr. Robert Hauser as the physician who went public in 2005 when problems surfaced with some models of Guidant heart defibrillators.

Hauser, of the Minneapolis Heart Institute at Abbott Northwestern Hospital, is also a prolific researcher in his field, and his latest project revealed some interesting results. In a study published recently in the medical journal Circulation, Hauser found that the recalled Sprint Fidelis implantable cardioverter defibrillator lead, made by Fridley-based Medtronic Inc., failed more often in younger patients, women and people with hereditary heart disease.

Med-tech followers may remember that the once-popular lead – an insulated wire that connects the device to the heart – was recalled in 2007 because a small number tended to fracture. Some 268,000 were implanted in patients worldwide at the time; Hauser estimates about 100,000 remain in patients.

Hauser and his colleagues observed lead performance at three major heart centers, his own, the Mayo Clinic and Beth Israel Deaconess Medical Center, a Harvard teaching hospital in Boston, from November 2001 to January 2009. He compared 1,023 patients with the Sprint Fidelis lead with 1,668 of those who had another Medtronic lead, called Quattro. The failure rate for Fidelis was 2.81 percent a year, compared with 0.43 percent with the Quattro lead. The survival of Fidelis leads at four years was 87 percent, compared with 98.7 percent for Quattro leads.

The researchers found that lead failure was not associated with death or serious injuries.

"We found that patients who were young and active with relatively normal pump function were at highest risk, as well as women compared with men," Hauser said.

Hauser said there's no reason to arbitrarily replace leads in patients, since the surgery to remove them may be riskier than just keeping the leads intact.

Medtronic spokesman Christopher Garland said the Hauser study "adds to the published body of knowledge that exists out there on this topic and is another data point physicians should consider."

He noted that Medtronic's CareLink monitoring system, which can follow pacemakers and defibrillators from afar, has gathered data of more than 20,000 patients – "the largest available sample size of Sprint Fidelis patients and, we believe, most representative of actual lead survival in the overall Fidelis patient population."