When 87-year-old Lee Koff received a new defibrillator implant in January at Lourdes Medical Center in Camden, he paid estimated out-of-pocket costs of $125. That was not much more than the $81 he paid in 2010 for his previous defibrillator, a device that regulates his heartbeat. But about two months after the January procedure, Koff, who has Medicare Advantage health insurance from Horizon Blue Cross Blue Shield of New Jersey, received a statement saying he owed Lourdes $6,071. Koff was dumbfounded. He and his daughter, Wendy Krevitz, said they had asked Lourdes office personnel if there were any other costs Koff would have to pay and were not told of any.