Medtronic ( MDT) shares dropped Monday after the medical device company suspended worldwide distribution of its Sprint Fidelis family of defibrillation leads because of the potential for the insulated wires to fracture. The leads are used in defibrillators, which monitor a patient's heartbeat and send a shock if necessary, in roughly 268,000 patients worldwide. The company said that data indicate the Sprint Fidelis lead viability is trending lower than the company's Sprint Quattro lead at 30 months, and while the difference isn't statistically significant now, it will be over time if the fracture rates remain steady. Medtronic said that of the 268,000 implanted leads, there have been five patient deaths in which a Sprint Fidelis lead fracture was a possible or likely contributing factor. Such a lead break could result in audible alerts, inappropriate shocks and/or loss of output. But the company and an independent panel are recommending that patients don't seek prophylactic replacement of the leads because risk of removal or insertion of another lead exceeds the risk of a lead fracture. Medtronic said the Food and Drug Administration will issue a statement as well. Medtronic shares were $7, or 12.4%, lower at $49.33 in recent trading Monday.