Medtronic is fending off more questions about the reliability of one of its cardiac devices, the Sprint Fidelis lead, a wire which connects a defibrillator to the heart.

The Wall Street Journal reports that the defibrillator wires fail more often than Medtronic says they do. The publication cited reports from the Mayo Clinic and other medical centers, which found failure rates two or more times greater than Medtronic's calculation of roughly 5 percent.

Dr. Paul Friedman of the Mayo Clinic authored one study. He says defibrillators save lives and any manmade device will have failures. But he says his and other studies show there's reason to reconsider how often the Sprint Fidelis defibrillator wires fail.

MPR News, by Martin Moylan, 2/4/2010

Tags: Business Relations, Cardiology, defibrillators, Medtronic