Medtronic Issues Alert on Sigma Pacemakers

Medtronic Inc., the world’s biggest maker of electronic heart devices, said it was notifying doctors about a potential defect in certain Sigma series pacemakers after some patients said they felt dizzy or fainted.

No deaths or injuries were reported, a spokesman for Minneapolis-based Medtronic said. About 28,000 pacemakers, including 6,650 in the U.S., are covered by the advisory.

Medtronic said the defect occurred when a solvent used to clean pacemaker wires degraded them over time, causing the wires to break from the circuitry in 19 devices.