St. Jude Medical Inc. will stop selling the QuickSite and QuickFlex left-ventricular leads, wires that help pace the heart in patients with heart failure after 39 reports of the wires protruding from their insulation. No one has been harmed by the defect, first seen in wires removed from patients because of infection or other unrelated issues, said Mark Carlson, chief medical officer of St. Paul, Minnesota-based St. Jude. The flawed wires were covered by a second layer of insulation and worked properly, Carlson said. St. Jude has been grappling with the same problem in its recalled Riata wires that connect life-saving defibrillators to the heart. QuickSite and QuickFlex help the heart beat in a coordinated rhythm rather than provide a life-saving jolt after it stops, like Riata. All three products have been supplanted by wires from St. Jude that are coated with newer Optim insulation.