Medtronic defends device against critical studies

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.

"The independent studies done by hospitals who are following patients in the real world suggest that we need to carefully consider the analysis, and work to identify who is at highest risk," said Friedman.

Medtronic spokesman Christopher Garland says the hospital studies involved too few patients to be reliable.

"We believe that our data, which includes more than 20,000 patients, is actually more likely to reflect the actual lead performance out there in the clinical experience than these small, single center studies," said Garland.

Medtronic stopped selling the wires in 2007, but about 150,000 people already have them implanted. Generally, doctors leave the wires in place, figuring surgical removal poses a greater risk to a patient.