Hundreds of injuries linked to a brand of heart defibrillator wires were reported to the government by last winter, a consumer advocate said Tuesday in asking why the wires weren't recalled until this week. Medtronic Inc. pulled its Sprint Fidelis defibrillation wires off the market Monday, after identifying five patient deaths in which broken wires may have played a role.

These wires, officially called leads, connect patients' hearts to a device that sends an electrical shock if it senses a life-threatening abnormal heart rhythm. A fractured lead can leave the defibrillator unable to send a lifesaving shock, or prompt it to deliver painful unnecessary shocks. The Food and Drug Administration had received 599 reports of malfunctions and injuries associated with the Fidelis leads as of Jan. 10, including 204 where patients had been inappropriately shocked, according to a count by the consumer group Public Citizen.